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CHEMICAL

WEED CONTROL

INFOBMATION

[or North Carolina

1968

Puazai r

W. M. Lewis, A. B. Rogerson, A. D. Worsham, and T. W. WaldrepCrop Science Department

andW. A. Skroch and T. J. Monaco, Horticultural Science Department

Reprinted from 1968 Pesticide ManualNorth Carolina State University

II.

III.

IV.

VI.VII.VIII.

IX.

XI.XII.XIII.XIV.XV.XVI.

TABLE OF CONTENTS

Weed ControlGeneral Information

PageIntroduction ........................................... 1Principles and Terms Used in Weed Control ............. 1A. Basic Terms ....................................... 1B. Classification of Herbicides .......................... 1C. Persistence in the Soil .............................. 2D. Application Terms ................................. 3E. Formulation and Spray Mixtures .................... 3F. Classification of Weeds ............................. 4Cautions in Handling and Applying Herbicides ......... . 4A. Human Safety ..................................... 5B. Livestock Safety .................................... 6C. Crop Safety ........................................ 6

1. Drift Hazards .................................. 62. Contaminated Equipment ........................ 73. Excessive Herbicide Rates ....................... 84. Growth of Roots of Other Plants into

Treated Areas .................................. 95. Movement by Washing or Leaching ............... 9

4. Safety to Game and Fish ............................ 91. Relative Toxicity of Herbicides to Mammals . . . . . .10

Common, Chemical, and Trade Names of Herbicides ....... 12Weed Identification .............................. . . . .14Publications on Weed Control ........................... 15Chemical Control of Woody Plants ...................... 16Chemical Control of Aquatic Plants .................. . .17

Specific Weed Control InformationChemical Weed Control in Hay Crops and Pastures ....... 20

. Chemical Weed Control in Field Crops .................. 21Chemical Weed Control in Vegetable Crops .......... . . .26Chemical Weed Control in Fruit Crops ............ . . . .30Chemical Weed Control in Woody Ornamentals . . . ..... 33Chemical Weed Control in Floral Crops ...... . . . . . . . . .34Chemical Weed Control in Lawns and Turf ....... . . .35Chemical Control of Specific Weeds ......... . . . . . . . . .37

WEED CONTROLW. M. LEWIS, A. B. ROGERSON, and W. A. SKROCI-I

GENERAL INFORMATIONINTRODUCTION

The field of weed control continues to grow rapidly as a science andin terms of chemical usage and cropland treated. In 1967 it wasestimated that about one and one-half million acres of agronomic rowcropland was treated in North Carolina. The addition of pasture andhay crops, horticultural crops, home lawns, and industrial siteswould increase this acreage treated considerably. Farmers in NorthCarolina spend well over 6 million dollars annually for herbicides.

In order to take advantage of and properly use the many weedcontrol chemicals which are now available, weed control workers needto have a general understanding of some of the principles of chemicalweed control. A knowledge of terminology is also necessary.

PRINCIPLES AND TERMS USED IN WEED CONTROLA. BASIC TERMS—A weed is a plant growing out of place.

Weed control is the process of limiting weed infestation so that cropscan be grown profitably or other operations can be conducted efl‘ici—ently. Weed eradication means the complete elimination of all liveplants, plant parts, and seeds of a weed infestation from an area.Noxious weeds are arbitrarily defined by law as being especially un-desirable, troublesome, and difficult to control. Definition of the term“noxious weed” will vary according to legal interpretations.

B. CLASSIFICATION OF HERBICIDES—Weed killing chemi-cals are called herbicides. Herbicides are grouped, on the basis of useinto selective and nonselective and, on the basis of mode of action,into contact, translocated or growth regulator, and sterilant chemi-cals.A selective herbicide is more toxic to some plant species than to

others. The reasons for selectivity in some cases is known; in othersituations, they are unknown. A non-selective herbicide is generallytoxic to plants without regard to species.A contact herbicide kills primarily by contact with plant tissue

rather than as a result of translocation. These chemicals are effectiveagainst annual weeds but only “burn off” the tops of perennial weeds.Contact herbicides may be (1) selective or (2) non-selective.

Translocated herbicides are also called growth regulators and sys-temic herbicides. Translocated chemicals may be absorbed by theleaves and stems or by the roots. When absorbed by the leaves andstems, the chemical commonly moves with the food materials manu-factured there. An overdose on the leaves may kill the immediatecells quickly and thus prevent effective translocation. When absorbedby the roots, the translocated chemical moves in the water-conducting(xylem) tissue of the plant.A soil sterilant prevents the growth of plants when present in the

soil. It does not necessarily kill all life in the soil, such as fungi, bac-teria, and other micro-organisms. The toxic effects may remain foronly a short time or for years.

C. PERSISTENCE IN THE SOIL—The length of time that aherbicide remains in the soil is extremely important as it relates tothe length of time that weed control can be expected. Also, residualtoxicity is important because of possible injury to succeeding sensi-tive crops.

Factors effecting the persistence of a herbicide in the soil are:(1) microorganism decomposition, (2) chemical reactions, (3) ad-sorption on soil particles, (4) leaching and solubility, (5) volatility,(6) photodecomposition, and (7) rate of application.

( 1) Microorganisms in the soil (algae, fungi, actinomycetes, andbacteria) are able to use many herbicides as sources of raw energy(food) and decompose the chemical or alter its structure to make itherbicidally inactive. (2) Some herbicides disappear partly becauseof decomposition by chemical processes in the soil such as oxidationand hydrolysis. (3) Some herbicides are readily adsorbed by mineraland organic colloids and rendered unavailable or made slowly avail-able for plant absorption. The fertility and pH of a soil also influencethe persistence or availability of certain herbicides. (4) Movementof water through the soil can remove herbicides from surface layersor reduce the concentration in upper soil layers. Generally the morewater soluble a chemical is, the easier it leaches. (5) Herbicides mayevaporate and be lost to the air as a gas. The effectiveness of highlyvolatile herbicides is rapidly lost if they are not incorporated intothe soil. (6) A few herbicides are decomposed by light. If such achemical remains on the surface of a soil for an extended period oftime, it may decompose. (7 ) High rates of application generally lastlonger than low rates.

D. APPLICATION TERMS—(1) Chemical dosage—Rate refersto the amount of chemical applied per unit area (such as one acre).Rate is given in terms of acid equivalent (the theoretical yield ofparent acid from an active ingredient) or active ingredient (thechemical compound in a product that is responsible for the herbicidaleffects). Concentration refers to the amount of active ingredient oracid equivalent in a given volume of liquid or in a given weight ofdry material. Recommendations and specifications for concentrationsof herbicides should be on the basis of pounds per unit volume ofliquid formulation or percent by weight of solid material.

(2) Time of Treatment—The time of application may be given withrespect to the crop, or with respect to the weed. Preplanting treat-ment is made before the crop is planted. Preemergence is a treatmentmade prior to emergence of a specified crop or weed. Postemergencetreatment is made after emergence of a specified crop or weed.

(3) Area or Type of Application—A soil application is made pri-marily to the soil surface, rather than to vegetation. Soil incorpora-tion would mean mechanical mixing of the herbicide with the soil.Soil injection is mechanical placement of the herbicide beneath thesoil surface with a minimum of mixing or stirring. A broadcast appli-cation is a uniform treatment over an entire area and a band applica-tion usually means treating a narrow strip directly over or along acrop row. Directed sprays are applied to a particular part of a plant,usually to the lower part of the plant stem or trunk. A basal treatmentis a spray applied to the stems or trunks of plants at and just abovethe ground line. Spot treatment is treatment of a restricted area,usually to control a small infestation of a weed species requiringspecial treatment.

E. FORMULATIONS AND SPRAY MIXTURES—Herbicidesare formulated to be applied as (1) solutions in water or oil, (2)emulsions, (3) wettable powders, and (4) granules. The carrier is theliquid or solid material added to a chemical compound to facilitateits application in the field. The diluent is any liquid or solid materialserving to dilute an active ingredient in the preparation of a formula-tion. An emulsifying agent, often added to liquid formulations, is asurface active material which facilitates the suspension of one liquidin another. An emulsion is the suspension of one liquid as minuteglobules in another liquid; for example, oil dispersed in water. Aninvert emulsion is thick suspension of water droplets in oil.A surfactant is a material which facilitates, and accentuates the

emulsifying, dispersing, spreading, wetting, or other surface-modify-3

ing properties of herbicide formulations. Wetting agents cause aspray solution to contact plant surfaces more thoroughly. A solutionis a physically homogeneous mixture of two or more substances. Asystem consisting of very finely divided solid particles dispersed ina solid, liquid, or gas is a suspension. A mixture of a wettable powderin water is a suspension.Compounds are said to be compatible when they can be mixed and

applied satisfactorily with effective results. Miscible liquids are thosecapable of being mixed, which will remain mixed under normal con—ditions. The cooperative action of different chemicals, such that thetotal effect is greater than the sum of the independent effects, isknown as synergism.A compound is volatile when it evaporates or vaporizes (changes

from a liquid or solid to a gas) at ordinary temperatures on exposureto the air. Vapor drift is the movement of herbicidal vapors from thearea of application. The movement of airborne spray particles fromthe intended area of application is spray drift.

F. CLASSIFICATION OF WEEDS—A plant’s length of life,the time of year that it grows, and the methods of reproduction arevery important factors in determining the method or type of herbicideneeded for control. According to growth habits plants are groupedinto: (1) annuals, (2) biennials, and (3) perennials.

(1) ' Annuals—complete their life cycle from seed in less than oneyear. They propagate by seed. Two types of annuals are (a) summerannuals and (b) winter annuals. Summer annuals germinate in thespring and mature and die in the fall. Winter annuals germinate inthe fall and winter and usually mature seed in the spring or earlysummer before dying. Most are prolific seed producers.

(2) Biennials require two seasons to complete the reproductioncycle. They propagate by seed.

(3) Perennials live for more than two years and may live almostindefinitely. Most produce seed each year. Also, many are able tospread uegetatively. Vegetative means of reproduction are by creep-ing roots, creeping above-ground stems (stolons), creeping below-ground stems (rhizomes), and by tubers.

Contact or translocated chemicals may kill annuals, but trans-located chemicals are needed to control perennials.

CAUTIONS IN HANDLING AND APPLYING HERBICIDESNearly all herbicides are potentially dangerous in one way or an-

other, but they are not likely to cause injury if used properly and If

recommended precautions are observed. Possible dangers may be to:operator and handler, livestock, desirable plants, equipment andSprayers through contamination, and game and fish.

The best general advice for safe use of herbicides is found on thelabel: Read the label on each container before using the product.Follow instructions; heed all cautions and warnings. Store in originallabeled containers. Store separately from seeds, fertilizers, insecti-cides, fungicides, and other pesticides. Dispose of empty containersby burying them at least 18 inches deep in an isolated area away fromwater supplies. Do not drain or flush spray equipment near desirableplants or where sources of domestic or irrigation water will be con-taminated.

A. HUMAN SAFETY—Although most herbicides are relativelynontoxic to man a few are very toxic. Read and follow instructionson the label to avoid injury. Poisoning can occur from swallowingsome herbicides, from skin absorption, or from inhalation. In eachcase, there is greater danger from the concentrated material thanfrom the diluted spray solution or suspension.The relative degree of toxicity of herbicides is indicated in Table 1.

The ratings describe the acute (not chronic) lethality of each herbi-cide when swallowed by laboratory animals. Most figures are basedon the adult white rat and for the technical material. Where a rangeof various figures was given for a compound, the lowest value wasused in the list. Usually toxicity in the field is less, because seldomis such a dose swallowed or absorbed and diluted sprays are handledmore often than concentrates.Humans do not always react like small animals. It is always possi-

ble that a human will stand a correspondingly larger dose of a givenchemical than results with animals would indicate or vice versa.There is no way to determine accurately whether a lethal dose forman is larger or smaller than the LD50 (lethal dose for 50% of ani-mals tested) for a laboratory animal. But animal studies are the bestguide available.Some individuals are hypersensitive to certain chemicals and have

allergic reactions. Keep exposure to a minimum. Wash hands andface with soap and water after handling. For more readily absorbedchemicals and those that are known to be irritating, wear clean cloth-ing that covers the body. Remove clothing after it has become con-taminated.Where splashing or dust may occur, wear goggles. Ordinary glasses

or sunglasses offer a great deal of protection from splashing or spray.

5

Use a mask when label directions indicate the need to avoid inhalingvapors or spray mists. Some herbicides are dyes that can color skinor hair, if not protected.

B. LIVESTOCK SAFETY—The majority of herbicides are non-toxic to livestock after being sprayed on plants. The chief dangers ofpoisoning to livestock are from the consumption of herbicide rem-nants in open containers and of contaminated water.The palatability of some plants not ordinarily eaten may increase

after spraying with 2,4-D or similar compounds. If the plants arepoisonous they may be eaten and sickness or death may result fromthe naturally toxic plant. Make sure that animals do not have accessto poisonous plants which have been treated with herbicides.The nitrate content of some plants may be increased after spray-

ing with 2,4-D. This nitrate is reduced to nitrite by micro-organismsin the intestional tract of herbivorous animals and cause poisoning.However, increased nitrate content of plants does not always followspraying. Furthermore, some natural conditions also produce highnitrate, so that many weeds contain enough to cause poisoningwhether sprayed or not.Changes in the label registration of the phenoxy herbicides now

require that milking dairy cows should be kept of? pastures sprayedwith 2,4-D or other phenoxy herbicides for 7 days after application.

C. CROP SAFETY—Improper herbicide use may cause seriousinjury to crops or desirable plants. Damage may result from: (1)drift, (2) contaminated equipment, (3) excessive herbicide rates,(4) growth of roots of non-treated plants into treated areas, and (5)movement of the herbicide by washing or leaching.

(1) Drift hazards are greatest with use of herbicides that affectthe leaves of plants. These may be of the growth-regulatory type, suchas 2,4-D, 2,4,5-T, and silvex or of the contact type such as PCP, thepetroleum oils, and dinitros. Vapor drift from the phenoxy herbicidescomes from use of volatile formulations. Use non-volatile formula-tions only such as amines or the acid. Spray drift is caused by spraythat has been atomized into a mist by high pressure and a small noz-zle opening. Winds blowing toward susceptible plants increase like-lihood of injury from spray drift. To prevent spray drift use lowpressure (10 to 30 psi for ground Sprayers) and a nozzle with a largeorifice (such as the hollow cone whirl-chamber nozzle) which gives acourse spray. Do not spray if the wind is blowing toward nearby sus-ceptible crops.

(2) Contaminated Equipment—It is extremely risky to use sprayerequipment that has been used for the phenoxy herbicides (2,4-D;2,4,5-T; etc.) to spray susceptible crops. Tobacco, cotton, and tomatoesare very susceptible.

There is not as much danger of crop injury where preemergencesprays are applied to susceptible crops from contaminated equipment.Postemergence applications of herbicides, insecticides, fungicides,etc. from contaminated equipment is where the greatest danger lies.Where possible, it is best to have separate spray equipment for

application of phenoxy herbicides. If, however, it is absolutelynecessary to use such equipment for other purposes special cleaningefforts must be made. The barrel or tank is the greatest source ofcontamination, probably followed by the hoses. The preferred choiceis to change barrels and possibly hoses. Where this is not practical,the following steps are suggested to remove 2,4-D and relatedmaterials from metal tanks.

a. Add a small quantity of water to the barrel. Slosh it aroundin the barrel. Empty. Repeat. If contaminated with chemicalssoluble in oil, use kerosene or fuel oil for both rinses. Estersof 2,4-D are oil-soluble. Amine salts of 2,4-D are water-solubleand can be removed from a non-rusted tank with thoroughrinsing with water plus a detergent.

b. Fill the entire system with water. Add a wetting agent ordetergent to the water used for this rinse. Repeat this rinse.Flush a part through the sprayer and empty the remainder.

c. If the ester form of 2,4-D was used in the sprayer fill the tankwith water and ammonia, add household ammonia at the rateof 1 quart of household ammonia to 25 gallons of water. Pumpenough solution through the hose and nozzles to completely fillthese parts. Then fill the tank, close and leave for 24 hours.Rinse thoroughly with water.

The addition of ammonia to equipment contaminated with2,4-D does not “deactivate” or “kill” the 2,4-D. It only convertsester forms of 2,4-D to water-soluble ammonium salts. Thenthese 2,4-D salts must be completely washed out of the sprayer.

d. The day before using the sprayer rinse again with clean water.Activated charcoal is also useful for cleaning herbicides

from spray equipment. Usually, 2,4-D and similar herbicidescan be removed by rinsing the sprayer for about 5 minuteswith a 0.3% suspension of activated charcoal (1/4, lb. activated

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charcoal in 10 gallons water containing a household deter-gent.) Drain. Throughly rinse with clean water.

Regardless of which method you use for decontamination,it is advisable to test the spray. Fill the sprayer with waterand spray seedlings of a sensitive test plant, such as bean,tomato, or cotton. If the plant is not affected within 2 or 3days, the equipment is safe for further use.For wettable powder herbicides, examine the tank to see

that none of the wettable powder remains caked in the bottom.A thorough rinsing with water and a detergent is usuallysuflicient for cleaning. Take screens and nozzles apart. Besure no material is left in these parts.

For most water-soluble herbicides, repeated rinsing withwater is usually enough.

Kerosene and fuel oils help carry away herbicides known tobe oil-soluble. Chemicals which form emulsions when mixedwith water are usually oil-soluble. Following an oil rinse,several rinsings with a wetting agent in water will helpremove the oil.

(3) Excessive Herbicide Rates—Apply only the amount recom-mended on the label of the product. Many chemicals are persistent inthe soil and slight excesses may remain in a field to injure succeedingcrops. Know how much water your sprayer applies per acre beforeyou add any chemical. Nozzles wear during use, especially nozzleswith brass tips and when wettable powders are used. Calibrate thesprayer before starting the spraying season and 2 or 3 times duringthe season. Be sure the sprayer has adequate agitation for wettablepowders. First a pump with a 10 to 12 gallons per minute capacityis needed for tractor mounted Sprayers. Adequate agitation can thenbe maintained by use of the supplementary “jet-agitator” or byreturning 2 to 3 gallons per minute into the bottom of the tankthrough the by-pass line.Never add concentrated herbicide to an empty sprayer. Add 1/1. to

1/3 tank of water first then add chemical with agitation. Do not letSprayers containing wettable powders stand idle for more than anhour or two. Before resuming spraying check bottom of tank to besure no herbicide has settled out.

If Sprayer has to stop in field cut off boom and move sprayer toedge of field to avoid drippage if sprayer is not equipped with non-drip nozzles. Do not take hoses loose or spill concentrated herbicidein fields. Be sure spray swaths do not overlap when spraying.

(4) Growth of Roots of Other Plants into Treated Areas—theroots of nearby desirable plants, especially trees and shrubs, maygrow into an area which has been treated with a herbicide. Herbicides,especially if used at soil sterilant rates, should be used with cautionwhen roots of adjacent plants may extend into the treated area.

(5) Movement by Washing or Leaching—Washing is an impor-tant hazard on slopes, bare ground, and pavements. The herbicidemay be carried by surface runoff to valuable plants downslope. Donot drain a flush equipment where runoff to desirable plants mayoccur.

Leaching moves chemicals downward and sometimes laterallythrough the soil. Plants whose roots come into contact With theherbicide may be killed or injured. Use care in applying heavy ratesof chemicals near or under desirable plants and on slopes. Do notdrain or flush equipment Where leaching to the roots of desirableplants may occur.

D. SAFETY TO GAME AND FISH—Most herbicides are lessdangerous than insecticides to wildlife. There are a few, however,such as the arsenicals and dinitros, that can poison animals. Mostinjury results from overdoses and spillage. Promiscuous sprayingand spraying that results in killing vegetation of similar species candestroy cover, but herbicides can also be useful in Wildlife manage-ment. Openings in wooded areas, such as the clearings for utilitycompany rights-of—way and spraying of hardwoods in stands of pinecan be beneficial to wildlife.A few herbicides are very toxic to fish, but many can be used

safely for the control of aquatic weeds. The control of submergedweeds in ponds or streams can be beneficial to fish populations. Safeamounts of herbicides, expressed in parts of the chemical per millionparts of water, vary widely with age, size, and species of fish.Do not drain or flush spray equipment where the chemicals can

wash into fish ponds or streams.

“Despite the use of billions of pounds of pesticides on millions of acres of crop-land, damage to wildlife has been relatively insignificant and in the vast majorityof cases undetectable.”Academy of Sciences—National Research Council—A Symposium on Pest Control and Wildlife Relationships—National

TABLE I. RELATIVE TOXICITY OF HERBICIDES TO MAMMALSBASED ON ACUTE ORAL LDw VALUES FOR ADULT WHITE RAT WITH TECHNICAL MATERIAL

Toxicity of Commercial Formulations Is Usually Lem Than Technical MaterialCommon Name Some Common LDm Toxicity‘ Dermal Responseor Designation Trade Names Dim/Kr. Rating Rating“

Sodium granite Atlas A, Triox 10 2 1,2Methyl bromide Various brands 17 ppm (air) 2 2DNBP Sinox, Dow General 30 2 1Endothall Endothal, Aquathol 35 2 3Calcium arsenate Various brands 35 2 4PMA PMAS, Tat-C-Lect 40 2 2DNBP (amine) Premerge, Sinox PE 40 2 1Acrolein Aqualin 46 2 2Kerosene Various brands — 2-3 _Pyriclor Daxtron 80 3 5KOCN Various brands 85 8 —Pal-squat Paraquat 157 3 2Gasoline Various brands —— 3 ._Aromatic solvents Various brands —- 3 ._PCP (Na. salt) Weedbeads 210 3 1Cypromid Clobber 218 3 —Bromoxynil Buctril, Brominil 260 3 42.45.3 Various brands 300 3 4Copper sulfate Various brands 300 3 .——— Ortho 0-56 300 3 1,2onynil Certrol, Bentrol 305 3 —Diallate Avadex 395 3 8Diquat Diquat 400 3 2CMA Super-Dal-E-Rad 440 8 —Silvex Kuron, Weedone-TP 500 4 42,4-DB Butyrac, Butoxone 500 4 42.4-D Various brands 500 4 4DMTT Mylone 500 4 4Petroleum solvents Various brands — 4 1Molinate 0rdram 501 4 4Bandane Bandane 540 4 —Swep Swep 552 4 ——DSMA Sodar, Ansar, Methar 600 4 5Mecoprop Mecoprop. Mecopex 650 4 —MCPA Various brands 700 4 4MSMA Weed-E-Rad, Ansar 700 4 —MAMA Ansar, Methar 720 4 —CDAA Randox 750 4 2ASPRIN (For Comparison) 750 4 5Bensulide Betasan, Pre-San 770 4 —SMDC Vapam 820 4 32,4-DEP Falone 850 4 4CDEC Vegadex 850 4 IDiphenamid Dymid, Enide 960 4 5PBA Benzac, Zobar 960 4 —Ametryne Ametryne 965 4 —Cacodylie acid Ansar 560. 120 1,000 4 —Sesone Sesone 1,000 4 —Erbon Baron, Novon 1.000 4 3DlVIPA Zytron 1.000 4 —-Dicamba Banvel D 1.040 4 —Trifluralin Treflan 1,050 4 —Pebulate Tillam 1,120 4 —Propachlor Ramrod 1,200 4 1,3HCA HCA Weed Killer 1.290 4 —Bax-ban Carbyne 1,350 4 4Dichlone Phygon 1,380 4 3Pronanil Stam F-34, Rogue 1,384 4 3.4Calcium cyanamide Aero—Cyanamide 1,400 4 ——_——— Lambaat 1,400 4 5Linuron Lorox 1,500 4 --AMS Ammate 1,600 4 5EPTC Eptam 1,630 4 —2.3:6-TBA Tryben. Benzac 1,644 4 5Trmllate Avadex BW 1,675 4 4NPA Alanap (Na. salt) 1,770 4 5Vernolate Vernam 1,780 4 —Metobromuron Patoran 2,000 4 4R-2063 Ro-Neet 2,000 4 4Monuron + 'I‘CA Urox 2.300 4 —10

Table ‘I. (Con't.) Relative Toxmty of Herbicides to MammalsCommon Name Bone Com-on Ll)so Toxicity Donn-l lessons.or Designation Trade Names Dim/Kg. Rating‘ Rating”

MH (amine) MH-30 2.340 4 5Norea Herban 2,500 4 —Box-ate Borax, Borascu 2,500 4 4Tok E-25 2,630 4 —-D EPTC Knoxweed 2,710 4 4zfifiome‘tbne Prometone 2.980 4 —-Fenac Fenac 3,000 4 —DcpA Dacthal 3,000 4 5IPC Propham 3.000 4 5Atrazine Atrazine 3,080 4 5TABLE SALT (For comparison) 3,320 4 5TCA Various brands 3,870 4 2Diuron Karmex 8.400 4 4Amiben Amiben, Vegiben 3,500 4 —Pyr‘zon Pyramin, 3,600 4 —Monuron Telvar 3,600 4 5Chloroxuron Tenoran 3,700 4 5Prometryne Caparol 3,750 4 ——R-1910 Sutan 3,997 4 8Fenuron + TCA Urab 4.000 4 -AMS Ammate X 3,900 4 5Dichlobenil Casoron 4.250 4 4Amitrole-T Amitrol-T, Cytrol 5.000 4-5 5CIPC Chloro-IPC 5,000 5 5Simazine Simazine 5.000 4 5Propazine Propazine 5,000 4 -—Nitralin Planavin 5,000 5 5Terbacil Sinbar 5,000 5 5Bromacil Hyvar X 5,200 5 4Fenuron Dybar 6.400 5 4DCU cm: 6.680 5 —Siduron Tupersan 7.500 5 4Picloram Tordon 8,200 5 —Fluometuron Cotoran 8,900 5 5Dalapon Dowpon 9,300 4 4Benefin Balan 10.000 4 -—Solan Solan 10,000 5 -Sodium Chlorate Atlacide 12,000 5 4Amitrole Amino Trizole, Weedazol 15,000 8 4UC-22463 Sirmate 18,700 6 —Terbutal Azak 34,600 6 —

' Numerical toxicity rating is based on a modification of the classification of pesticides in the FederalInsecticide, Fungicide, and Rodenticide Act and from "Clinical Toxicology of Commercial Products byGleason, M. N., Gosselin, R. E., and Hodge. B. D. Williams and Wilkins 00., Baltimore. Md., 1957.

Toxicity Rating

QMhWNt-I

Class-Extremely ToxicVery toxicModerately toxicSlightly toxicAlmost NontoxicNontoxic

LD”. (mm/ks.)less than 55 to 4950 to 499500 to 4.9995.000 to 14.99915,000 and above

” Numerical rating is based on the following classification:4. Mildly Irritating1. Absorbed and poisonous2. Causes burns and blisters3. Moderately Irritating

Probable Lethal Dosefor 150-lb. InnA taste (less than 7 drops)7 drops to 1 teaspoonful1 teaspoonful to 1 ounce1 ounce to 1 pint (1 pound)1 pint to 1 quartmore than 1 quart

5. Nonirritating

11

IV. COMMON, CHEMICAL, AND TRADE NAMES OF HERBICIDESChemical CommonFamily Name Chemical Name Some Trade Names

Aliphatic dalapon 2,2-dichloropropionic acid (sodium salt) Dowpon, Radaponacids TCA trichloroacetic acid (sodium salt) VariousAmides CDAA 2-chloro-N,N-diallylacetamide Randoxdiphenamid N,N-dimethyl-2,2-diphenylacctamide Dymid. Enidesolan N-3-chlorc>4-methylphenyl) -2-methylpentanamide Solanbensulide N-(2 mercaptoethyl) benzenesulfonamide Betasan, Pre—san,S-(0.0~diisopropyl phosphorodithioate) Turfbuilder plus 4Benzoic, amiben 3-amino-2,5-dichlorobenzoic acid Amiben, VegibenPhenylacetic dicamba 2-methoxy-3,6-dichlorobenzoic acid Banvel Dand fenac 2,3,6-trichlorophenylacetic acid FenacPicolinic PBA polychlorobenzoic acid Benazac 354. Z01“!acids 2,3,6-TBA 2,3,6-trichlorobenzoic acid Benzac 1281. Trysbcn 200picloram 4-amino—3,5,6-trichloropicolinic acid TordonCsrbamates CDEC 2-chloroallyl diethyldithiocarbamate VegedexCIPC isopropyl N-(3-chlorophenyl) carbamate Chloro IPCEPTC ethyl N,N-diprophylthiolcarbamate Eptam 6-E, 10 Gnnulltpebulate S-propyl-butylethylthiocarbamate Tillam B-ER—1910 ethyl-N—N—disobutylthiol carbamabeBMDC sodium N-methyldithiocarbamate VapamUC-22463 3,4-dichlorobenzylmethyl-carbamate (and 2, 3-isomers) Six-matevernolate S-propyl dipropythiolcarbamate Vernam 6-Eterbutol 2,6-di-tert.-butyl-p-bolyl methylcarbamate AzakHeterocyclic amitrole 3-amino-1,2,4-triazole Weedazol. Amino Triazolo.Nitrogen atrazine 2-chloro-4-ethylamino-6-isopropylamino—s-triazine Atrazine 80W, 8GDerivatives propazine 2-chloro-4,6-bis (isopropylamino)-s-triazine Propazine 80Wprometone 2-methoxy-4,6-bis (isopropylamino)-s-triazine Pl-ometone. Pramitolprometryne 2,4 (isopropylamino-6-methymercapto-s—trazine Caparol 80Wsimazine 2-chloro-4,6-bis (ethylamino)-a-triazine Simazine 80W, 4GMH maleic hydrazide MH-30Inorganic: AMS ammonium sulfamate Ammate, Ammate Xsodium arsenite Atlas A, Sodium Arlenitasodium chlorate Atlacide, Sodium ChlorateOrgano- CMA calcium acid methanearsonate Super Dal-E-RadMetalics DSMA disodium methanearsonate Sodar, Artox, Clout. Anna:and MAMA monoammonium methanearsonate Super Dal-E-Rad, MetharHalide: MSMA monosodium acid methanearsonate Weed-E-Rad, Ansar—— methyl bromide variousPMA phenylmercuric acetate PMAS, Tat-C-LectPhthalic DCPA 2,3,5,6-tetrachloroterphthalic acid (dimethyl ester) Dacthal, Rid,Compounds endothall 3,6-endoxohexahydrophthalic acid Endothal, AquatholNPA N-l-nsphthylphthalamic acid Alanap-3. 20GSubstituted DNBP 4,6-dinitro-o—sec-butylphenol Dow or Sinox GeneralPhenols DNBP (alkanolamine salts of above) Premerge, Sinox PE,PCP pentachlorophenol Napclor, WeedbeadsPhenoxy 2,4-D 2,4-dichlorophenoxyacetic acid Variouscompounds 2,4-DB 4-(2,4-dichlorophenoxy)butyric acid Butoxone, Butyrlc2,4-DEF tris(2,4-dichlorophenoxyethyl)phosphite Falone-44E, 10Gmecoprop 2-(2-methyl-4-chlorophenoxy propionic acid Mecopexsesone sodium 2,4-dichlorophenoxyethyl sulfate Amcbem Sesonesilvex 2-(2,4,5-trichlorophenoxy)propionic acid Kuron, Weedone 2,4,6-TP,2.4.5-T 2,4,5-trichlorophenoxyacetic acid Various (esters, amines)Toluidines benefin N-butyl-N-Ethyl-a.a-trifluoro-Z,6-dinitro-p-toluiline Balanand ' bromoxynil 3.5-dibromo-4-hydroxybenzonitrile Buctril, BrominilNitrlles dichlobenil 2,6-dichlorobenzonitrile Casoronioxynil 3,5<diiodo—4-hydroxybenzonitrile Certrol, Bentrolni‘ ralin 4- (methylsulfonyl) -2,6-dinitro-N—N-dipropylanaline Planavin‘trifluralin a,a ,a-trifluoro-Z , 6-dinitro-N,N-dipropyl-p-toluidine Treflan

12

IV. (Con’t.) Common, Chemical, and Trade Names of HerbICIdesChemical CommonFamily Name Chemical Name Some Trade Names

Ute-s and bromacll 5-bromo-3-sec-butyl-6-methyluracil Hyvar-XUncill chloroxuron 3-[p-(p-chlorophenoxy)-phenyl)-1,1-dimethylurea Tenorandiuron 3,(3.4-dichlorophenyl)-1,1-dimethylurea Karmex. Kamex DLfenuron 3-phenyl-1,1-dimethylurea DybarfBuometuron 3-(m-trLuoromethylphenyl)-1,1-dimethylurea Cotoranisocil 5-bromo-3-isopropyl-B—methyluracil Hyvarlinuron 3- ( 3,4-dichloropheny1) -1-methoxy-1-methylurea Loroxmeto- N-(p-bromophenyl) -N’-methyI-N’-methoxyurea Patoranbromuronmonuron 3- (p-chlorophenyl) 1.1-dimethy1urea Telvarnor-ea 3- ( hexahydro-4,7-methanoindan-5yl)-1,1-dimethylurea Herbansiduron 1-(2-methylcyclohexyl)-3-phenylurea Tupersanterbacil 3-tert-butyl-5-chloro-6-methyluracil SinbarOther diquat 6-7-dihydrodipyrido(1, Z-a:2’ 1'-c)pyrazidiinium salt Ortho Diquatcompounds DMTT 3,5-dimethyltetrahydro—1,3,5,2H-thiadiazine—2-thione Myloneparaqunt 1,1'-dimethyl-4,4’-bipyridinium salt Ortho Paraquatpropachlor 2-ch]oro—N-isopropylacetanilide Ram:-————-— 2,4 dichloropheny1-4-nitrophenyl ether Tok E-25

THE MOST EFFECTIVE PESTICIDE MAY BE USELESSWITHOUT PROPER APPLICATION

THINK! IS THIS THE PROPER DOSAGE?READ! WHAT DOES THE LABEL SAY?

KEEP PESTICIDES IN PROPERLY LABELED CONTAINERS

and

"Read the Label”

13

14

V. WEED IDENTIFICATION

Local common names applied to weeds are often misleading. A big bottle-neck in weed control lies in the area of plant identification. It should beunderstood that it is necessary that we identify correctly the weed whichis a problem before we can expect help in controlling it.No regular plant identification service is maintained at North Carolina

State. However, it is usually possible to get weed specimens identified ifthe following steps are followed:

A.1. Collect two good plants. Get complete plants which have leaves,

2.

Bl.

stem, roots and either flowers or fruit.Press and dry these specimens between old newspapers placed on aflat surface and weighted with a large book or a large board on top.When these plants are flattened and dry, prepare one of them formailing.Keep the second plant for your record. Small plants can be fasten-ed to cardboard and put into an envelope. Where more than oneplant is sent, please number the plants. If the plants are large,include a section of the stem with several leaves attached, thelower part of the stem and the roots, and a flower or fruit. Largeplants may be sent in boxes.Seal the envelope securely or pack and close the box securely toprevent breaking or crushing the plant,An alternate method of preparing plants is to send a fresh speci—men. This may be done by wrapping a fresh plant, including aportion of stem, leaves, roots, and flowers or fruit, in moist (notsoaking wet) newspaper or paper towel. Then wrap loosely inplastic, foil or waxed paper and put in a box strong enough toprevent crushing in the mail. Blot excess moisture from the plantif it is from an aquatic environment. Keep a dried plant for yourrecord.Address to: Agronomy Extension Specialist (Weeds), Crop Sci-ence Department, N. C. State, Raleigh, North Carolina, 27607.Write a letter explaining soil and location from which the plantwas taken. If growing in a crop, please note this as well as othercrops and desirable plants in the neighborhood. This informationshould accompany the envelope or box containing the plant orplants. Include full information for each plant by the numberyou have given it.

3. Allow ten days to two weeks for a reply. When you receive this re-ply, check your plant specimen carefully so that you will associatethe name with this particular plant.

A complete plant or a specimen containing leaves, stem, roots, andflowers or fruit is absolutely necessary to get a definite identification.Please prepare specimens properly and pack well. It is impossible toidentify a plant when only a leaf or stem is sent. Crushed specimens frompoor packing or specimens which are rotted from being tightly packedgreen are especially hard to identify.

VI. PUBLICATIONS ON WEED CONTROLAquatic Weeds

Waterweed Control on Farms and Ranches—USDA FB No. 2181Chemicals

Caution with 2,4-D, 2,4-5-T, MCP in Weed Control—Ext. Folder No. 107Chemicals for Weed Control—Ext. Cir. No. 378Using Phenoxy Herbicides Effectively—USDA FB No. 2183

EquipmentDrop Nozzles for Weed Sprayers—Ext. Folder No. 182Sprayers for Weed Control—Ext. Cir. No. 403The Hand Sprayer for Weed Control—Ext. Misc. Cir. Unnumbered. 1962.

Field CropsChemical Weed Control in Corn—Ext. Folder No. 148 (revised)Chemical Weed Control in Cotton—Ext. Folder No. 178 (revised)Small Grain, Chemical Weed Control—Ext. Folder No. 105 (revised)

GeneralChemical Weed Control Information for N. C.——M.isc. Pub., 1968 PesticideManual ReprintHerbicide Manual for Noncropland Weeds—USDA Agric. Handbook No. 269

Some Weedy Plants of N. C.—Ext. Cir. No. 390Stock—Poisoning Plants of North Carolina—Exp. Sta. Bul. No. 414 (Revised)Suggested Guide for Weed Control—1967. USDA, AR‘S, Agric. Handbook No. 332Herbicide Handbook of the Weed Society of America—F. W. SIlife, Dept. of Agron.,Univ. of Ill., Urbana, I11. ($3.00)

LawnsControlling Lawn Weeds With Herbicides—USDA H & G Bul. No. 79Weed Control in Lawns and Other Turf Areas—Ext. Misc. Mimeograph

Specific WeedsBermuda grass Control—Ext. Folder No. 114 (revised)Dodder and Its Control—USDA FB No. 2117Johnson grass as a Weed—USDA FB No. 1537Nutgrass (Nutsedge) Control—Ext. Circular No. 452So You Have Witchweed—Ext. Folder No. 152Watch Out for Witchweed—USDA PA—331

Woody PlantsChemical Control of Brush and Trees—USDA FB No. 2158Poison Ivy, Poison Oak, and Poison Sumac—Ext. Folder No. 144Paison-Ivy, Poison-Oak and Poison Sumac—USDA FB Bull. No. 1972

15

CHEMICAL CONTROL OF WOODY PLANTSA. D. WORSHAM, W. M. LEWIS, and HAROLD D. COBLE, Crop Science Department

Type of PlantsApplication Chemical Rate" Controlled Precautions and RemarksFoliage 2,4,5-T 6 lb. / Most woody Use amine formulations to reduce vapor drifttreatment amine 100 gal. species; ash, hazard. Use low spraying pressure to preventwater red maple spray drift. Wet foliage and stems thoroughly.and persim- Most effective results obtained by spraying with-mon generally in 6 weeks after plants have reached full leafresistant. stage. This treatment used primarily on trees orRhododendron brush less than 6 feet tall. A few species moreresistant. susceptible to 2,4-D.AMS 57 1b. / Most woody This treatment used primarily in areas near crops100 gal. species or plants very susceptible to 2,4,5-T. Thoroughlywater wet foliage and stems anytime during growingseason. Add 2 oz. spreader-sticker per 50 gal.spray mixture. Wash out sprayer thoroughly afteruse.Dormant 2,4,5-T 8 to 12 1b. / Most woody One of most effective treatments for control ofstem low 100 gal. species; black woody plants. Spray entire plant to good runofl.treatment volatile diesel locust resist- This treatment used primarily on woody plantsester fuel or ant less than 10 feet tall. Root suckering species whichoil produce shoots at some distance 'from the main_ stem may be resistant.Basal stem 2,4,5-T 8 to 12 lb. / Most woody One of most effective treatments for control oftreatment low 100 gal. species; black woody plants. Spray lower 12 inches of stem orvolatile diesel locust trunk and let some solution run into ground. Mayester fuel or resistant. be used any time of year but much more effectiveoil during dormant season. One growing season re-quired before plants die completely. This treat-ment used primarily on plants less than 6 inchesin diameter. Root suckering species may be resis-tant. Both dormant stem and basal treatmentsuseful to farmers and landowners because duringwinter there is less hazard to crops and morelabor probably available.Frill 2.4.5-T 12 1b. / Most woody Used primarily on trees greater than 6 inches intreatment low 100 gal. species diameter. Make one deep gash with an axe forvolatile diesel each 3 inches of circumference near ground. Putester fuel or 11/2 teaspoons of AMS per inch of trunk diameterOil in these gashes. Or make a continuous frill (seriesAM _ of gashes) around the tree trunk. Apply wettingS 2/00133 3:33.:de spray of AMS or 2,4,5—T in frill. Crystals of AMSgal. water may also be put in gashes.Stump 2,4,5-T 12 lb. / Most woody Soak freshly-cut stumps with spray solution totreatment low 100 gal. species prevent sprouting. Or use AMS crystals on stump.volatile diesel Hasten decay of stump by covering with layersester fulel or of soil and a nitrogen fertilizer. Keep moist.01AMS 1.5 tea- Most woodyspoons species/ in.diam.Tree 2,4.5-T 11/.) lb. Most woody Requires use of commercial tree injection tool.injection low / 41/2 species Make injections at the ground line. Leave novolatile gal. more than 2 in. between the edges of injectionester diesel gashes for trees up to 8 in. in diameter and nofuel or more than 1 in. between edges of gashes forkerosene trees greater than 8 in. in diameter.Soil diuron 32 lb. / Most woody Apply around base of trees and brush. Use broad-treatment or acre + 20 species cast or spot treatment. Will practically sterilizemonuron lb./yr. soil. Trumpet creeper and blackberry mayresistant. Repeat as necessary.simazine 32 to 40 Most woodylb. / speciesacrefenuron 12-18 Most woody Use 1 to 2 tablespoons of pellets on ground atlb. / species base of brush clumps and 2 to 4 tablespoonsacre spread around drip line. For black locust, sassa—fras, sumac, and other species with wide-spread-ing root systems, spread chemical over 2 to 4sq. ft. at base. Very effective on red maple andturkey oak. Works best on light sandy soils.‘ Rate based on pounds active ingredient or acid equiva16

lent.

LI

CHEMICAL CONTROL OF AQUATIC PLANTSW. M. LEWIS, A. B. ROGERSON, and A. D. WORSHAM, Crop Science Department

Type and kindof aquatic weed Chemical Rate orConcentration‘ Precautions and RemarksSUBMERSED WEEDS (TOPS MOSTLY UNDER WATER, USUALLY'ROOTED OR ANCHORED)Algae, blue-green Copper sulfate(pentahydrate,dark blue)

0.1 to 0.5 ppm Apply crystals or powder at early stages of algaegrowth by any method to give rapid and uniformdispersions. Repeat as necessary to maintaincontrol. Safe in potable water.Algae. filamentous Copper sulfate(pentahydrate,dark blue)Endothall (dimeth-ylamine salt)

0.5 to 1 ppm In soft water safe on most fish except trout.Safe in potable water11:02po In hard water injurious to most fish.Safe in potable water.0.05 to 0.2 ppm Apply uniformly over surface or inject belowwater surface.Rooted or anchored weeds:bladderwortcabombacoontailelodeanaiadpondweedlwatermilfoilwaterpennywortwaterstargnn

Endothall (disodium salt) 1to4ppm Apply at early stages of weed growth. Uselower concentrations in total area treatmentsand higher concentrations for margins. spottreatment or cold water. Follow label directionson use of treated water.Fenac 15 to 20 lb./acre Apply to temporarily exposed lake or pond bot-toms and shorelines when soil is not frozen.Keep water down at least 3 weeks. Follow labeldirections on use of treated water.Dichlobenil 7 to 10 lb./acre Apply to temporarily exposed lake or pond bot-toms and shorelines. Follow label directions ofuse of treated water.10 to 15 lb./acre Broadcast over water surface before or assoon as new growth begins in spring. Increaserates in water deeper than 3 feet and for spottreatment.Diquat (cation) 2 to 4 lb./acre Apply over surface or inject below water sur-face. Double rates for spot treatment. Rate de-termine by weeds present. Do not apply to mud-dy water. Follow label directions on use oftreated water.Same weeds as above,except elodea 2,4-D ester(granular) 20 to 40 lb./acre Apply uniformly over water surface at earlystage of weed growth using a cyclone seederor fertilizer spreader. Use heavy rates for moreresistant species or extremely acid or alkalinewater. Esters of 2,4-D toxic to some species offish at these rates.Silvex, potassiumsalt (granular or liquid) 1t02ppm Apply uniformly over surface of water or in-ject liquid below surface at early stage of growth.

8i CHEMICAL CONTROL OF AQUATIC PLANTS (continued)Type and kindof aquatic weed 1 Chemical 1 Rate orConcentration“

lI Precautions and Remarks

FLOATING WEEDS (UNATTACHED, TOPS ABOVE WATER)Alligatorweed (floating 2.4-1) amine salts or 2-4 lb./100 gal. Spray to uniformly wet foliage when weedsmats). duckweed, waterfern low-volatile esters diluent actively growing. Include 10 gal. fuel oil and(Salvinia), water-lettuce: 1 pt. emulsifier for waxy hard-to-wet foliageGeneral control (all weeds). or in rainy season. Repeat every 4 to 6 weeks.Near crops sensitive to Diquat (cation) 2 lb./acre Inject into water or spray on foliage when2.4-0:Duckweed(nonllowing water) actively growing. Much less effective in muddywater.Water-hyacinth andwaterlettuce Diquat (cation) 1-1.5 lb./acre Apply as surface spray in 150-200 gal. water oras aerial spray in 7.5 gal. water per acre whenactively growing.More positive eradication—alligatorweed floating mats Ester of silvex 8 lb./acre Apply as spray in 150-200 gal. water per acreat first bloom. Re-treat when regrowth 2 to 4inches above water. 2 to 4 applications requiredfor control.

EMERSED AND MARGINAL WEEDS (ROOTED WATER, TOPS ABOVE WATER, OR GROWING 0N WET SOIL)Arrowhead. lotus smartweed. 2, 4—D (low-volatile 1-4 lb./acre Apply in oil or in oil-water emulsion (1:10 orspatterdock, spikerush, water- ester) 1:20) in sufficient volume to give uniform cov-primrose. white water- erage. Spray when plants actively growing.lily, other plants wth waxyleavesRooted. emersed alligatorweed Ester of silvex 8 lb./acre Apply as spray in 160 to 200 gal. water per

(spiral!) acre at first bloom. Re-treat when regrowth 2to 4 inches above water. 2 to 4 applicationsrequired for elimination.Grass and grasslike species:Perennial grasses andledges. e.g., cutgrass,johnsongrau. knotgrass.commonrecd (Phraglnites“),ripgut sedge

Amitrole oramitrole-T 8 to 16 lb./acre Apply in 100 to 400 gal. water per acre asground spray or in 10 to 16 gal. water peracre as aerial spray when plants 6 to 18 inchestall and before heading; some grasses, e.g., reedcanarygrass, require 50 percent less amitrole-Tthan amitrole; use only in drainage ditches -andmarshes.Elapon 20 to 30 lb./acre Apply in 100 to 400 gal. water per acre asground spray or in 5 to 15 gal. water per acreas aerial spray. when grasses 6 to 18 inchestall and before heading; add 3 to 4 pt. wettingagent per 100 gal. water. Repeated light appli-cations at 5 to 10 lb. per acre are more ef-fective on some species, e.g., paragrass. Useonly in drainage ditches and marshes.

Bulrushes and cattails" 2. 4-D (low-volatileesters) 4 to 6 lb./acre Apply in 1:20 oil-water emulsion at 150-300 gal.per acre. Make initial application at first head-ing and repeat on regrowth before heading. 3to 4 applications necessary for elimination.

6i

CHEMICAL CONTROL OF AQUATIC PLANTS (continued)Type and kindof aquatic weed Chemical Rate orConcentration‘ Precautions and Remarks

Amitrole 6 to 12 lb./acre Apply at fully headed or postheading stage inlate summer or early autumn in sufficient vol-ume of spray to give uniform coverage by groundor aerial equipment. Apply at earlier growthstage for control during current season and re-peat as necessary to eradicate regrowth. Useonly in drainage ditches and marshes.Dalapon 15 to 30 lb./acre Same as for amitrole except include 3 to 4 pt.of wetting agent or 5 to 10 gal. diesel oil plus1 pt. emulsifier per 100 gal. spray.

* Rate or concentration is in terms of acid equivalent or active ingredient. Rates per acre refer to surface acre.1 ppm is 2.7 lb. active ingredient of a material per acre foot. An acre foot equals one surface acre one foot deep or 43,560 cubic feet."' Or for phragmites use 2 lb. amitrole plus 10 lb. dalapon. For cattail use 1 lb. amitrole plus 5 lb. dalapon.Note: Treatment of dense weed areas can result in oxygen loss from decaying weeds. This loss can cause fish suffocation. Therefore, treatonly part of dense weed areas at a time to reduce this problem.

Follow Label Direction

USE

PESTICIDES

PROPERLY

OZ

CHEMICAL WEED CONTROL IN HAY CROPS AND PASTURESW. M. LEWIS, A. D. WORSHAM, and T. W. WALDREP, Crop Science Department

Crop Chemical Rate/Acre‘ Weeds Controlled Precautions and RemarksAlfalfa-_ DNBP 1% to 3 lb. in Winter annual weeds such Spray dormant alfalfa (after second good frost orEstablished (amine salts) 30 to 60 gal. as cornflower (ragged earlier if weeds become severe) in fall. winter, or earlydormant water. robin or batchelor’s but- spring. Apply while weeds are as small as possible. Mayton), chickweed, henbit require a second treatment.sheperdspurse, b l e s a e dthistle.

Alfalfa: DNBP 1 to 2 lb. in Winter annual weeds such Spray when alfalfa is in 5-to-6-leaf stage (5 to 6 in.8°.“an (amine 88.1138) 30 to 60 gal. as chickweed, henbit, mus- tall) and dormant. Use 30 or more gal. of water perwater. tard, blessed thistle, corn acre going as high as 50 to 60 if weeds are large.flower (ragged robin or Spray when weeds are small as possible. Apply whenbatchelor's button). temperatures are 60°F. or more and no rain is expectedfor 12 hrs.

Lespedeaa- 2.4-1) amine 1,4 to 175 lb. in Ragweed and other sus- Common lespedeza, Korean lespedeza, and sericea les-eatablished 5 to 20 gal. ceptible annual broadleaved pedeza in the 6-to-8-leaf stage or larger, if healthy willwater. weeds. withstand up to 56 lb. 2,4-D per acre with little injury.Spraying during rapid spring growth, usually aroundthe month of April in the Piedmont, should be avoided.

Patturca- 2,4-D amine 1/5 to 1 lb. Curled dock, ragweed, bit- Spray when weeds are 4 to 8 in. tall and before head-Ladino clover, in 6-10 gal. terweed, pigweed, dande— ing. Clover may be stunted and growth retarded 3 to 601‘3th grass, water. lion and other broadleaved weeks. Use lower rate in warm, wet weather. 2,4,5-Tor fescue and weeds. may be used for some weeds resistant to 2,4-D butother grasses more injury to the clover may be expected than with2,4-D. For wild garlic apply late Feb. or early March.1 1b. Wild garlic Repeat for 3 years. Do not graze dairy animals ontreated areas within 7 days after application.

Perennial Grasses 2,4-D amine Jyéto 1 1b. Mustard, radish, cocklebur, Do not spray in seedling stages or just prior to head-tall fescue, in 6-10 gal. vetch and other suscepti- ing. Apply after the perennial grass seedlings haveorchard and water. ble broad leaved weeds. reached the 2-to-4 leaf stage. For wild garlic applyCoastal Feb. or March. Repeat for 2 years. Do not graze dairyBermudagrasa 3 lb. Wild garlic animals on treated areas within 7 days after application.

Coastal 2,4-D amine 1 lb. Young annual broadleaved Apply after sprigging. Gives little preemergence weedBermudagrau weeds. control. Later applications may be needed to controlbroadleaved weeds.

Simazine 1%to 3.2 lb. Most annual broadleaved Apply shOrtly after sprigging or to established ber-and grassy weeds. mudagrass from fall to spring depending on weedproblems, but before weed seeds germinate. Use lowerrate on light sandy soils. higher rate on heavier soils.Do not apply within 7 days following cutting. Do notgraze for 30 days after application when 1% to 2.4 lb.used and 60 days when 3.2 lb used. Do not cut forhay for 60 days after application when 1% to 2.4 lb.used and 90 days when 3.2 lb. used.

IZ

CHEMICAL WEED CONTROL IN FIELD CROPSCrop Chemical Rate/Acre' Weeds Controlled Precautions and Remarks

Corn Atrazine or simazine 2 to 4 lb. Annual broadleaved and Use lower rate on light soils. higher rate on heavyPreemergence in 10 to 30 grassy weeds. soils. Do not use 2,4-D on sandy soils as injury to crop

gal. water. is likely. Atrazine or simazine controls annual grassesmuch better than 2,4-D and has longer residual control2.4-D amine 1 to 2 lb. in Most annual broadleaved (6 to 8 weeks for simazine or atrazine. 2 to 3 weeks

6 to 10 gal. weeds and some annual for 2,4-D). Shallow rotary boeing or cultivation maywater. gram. improve eflectiveness of atrazine and simazine, espe-cially if drought follows application.Apply 2,4-D one to 2 days before emergence through“spike” stage (before leaves open).

Propachlor 5 lb. Most annual grassy and TRIAL USE ONLY. Use on high organic soils inbroad-leaved weeds. eastern part of state only. Under favorable condi-Cocklebur and smartweed tions should give 3 to 5 weeks control. Rain neededcontrol poor. following application for effective control. Cultivateor spray 2,4-D postemergence when needed forbroadleaf control. Cultivate for gram when effective-ness of chemical is gone.

Poatemergenee 2,4-D amine 1/4 to ’73 lb. Cocklebur, pigweed. rag- Use 54 lb. 2,4-D over top when corn is 4 to 6 inchesin 6 to 10 gal. weed, lambsquarters, morn- tall and weeds are small. Increase rate to 1,9 lb. aswater. ingglory. corn reaches 10 to 12 inches. Use drop nozzles anddirect spray toward base if corn is over 12 inches tall.15 to 554 lb. Smartweed, seedling par- Do not cultivate for about 10 days after spraying asin 6 to 10 gal. tridge pea or sicklepod. corn may be brittle. Reduce rate of 2.4-D if extremelywater. hot and soil is wet. .

Atrazine 2 to 4 lbs. Most annual broadleaved Atrazine can be sprayed over top of corn. Must bein 10 to 30 and annual grassy weeds. applied before weeds are over one inch tail to be eflec-gal. water. tive. Not efiective during drought.

Nitrogen solution plus 80 to 120 lb. This treatment kills an- "Have field clean when corn is 12 in. tall. Apply nitro-one of additives listed N/acre nual weeds that are less gen solution and additive as broadcast spray to lowerbelow: than one in. tall. Keeps 3 to 4 in. of corn stalk when corn is 20 to 30 in. tall.atrasine 1 lb. field clean until harvest. Cover middle also. Special spray equipment that willlinuron 0.62 lb. stand the nitrogen solution is needed to apply theseDiuron (w. p.) 0.6 lb. mixtures. Agitation is required.2,4-D (“Weedone 638") 0.3 lb. When using 2,4-D amine. add IA lb. of 2,4-D amine to2,4-D (“Singleshot”) '76 lb. 2 qts. water and mix. Then add this mixture to the2,4-D amine V; lb. nitrogen solution with considerable agitation untilthoroughly mixed. Do not allow to stand in sprayer.

Cotton Trifluralin 1,4 to 1 lb Annual grassy weeds and Incorporate into soil 2-3 inches deep immediately afterPuphnfing some broadleaved weeds. application. Thorough and uniform incorporation is aPoor to no control ofcocklebur, morning glory.and ragweed.

necessity. label for incorporation instructions. Ifstand failure occurs, cotton may be replanted or soy-beans planted. Retreatment is unnecessary. Rates of 1Ato 9’4 lb./acre are sufficient for Coastal Plain. % to 1lb. may be required in Piedmont especially for pigweedcontrol. If properly applied no injury to fall or springseeded crops is expected. Under certain conditionstemporary stunting of cotton seedlings may occur.

ZZ CHEMICAL WEED CONTROL IN FIELD CROPS (Cont’dJCI'OP Chemical Rate/Acre‘ Weeds Controlled Precautions and Remarks

Cotton (con't.) Nitralin 3!. to 1 lb. Same as for trifluralin. Incorporate 1 to 1% in. deep within 2 hrs. after appli-Preplsnting cation. Other remarks same as for trifluralin. If pre-01' plant treatment is used, take extreme care whenPremergence planting not to turn up untreated soil. If preemergencetreatment is used. take extreme care in incorporatingnot to disturb seed or cover seed too deeply.Preemergence Diuron IA to 1 lb. Annual grassy weeds and Apply at planting or immediately after. Usually get 4Prometryne 1.6 to 2_4 lb. some broadleaved weeds. to 6 weeks control. Rainfall needed after applicationC to l Prometryne more effective for eflectiveness. If drought occurs, use shallow rotary° ran 1'0 to 2-0 b- on broadleaved weeds than hoeing or sweep cultivation. If stand failure occurs.DCPA 6.0 to 9.0 lb. diuron. Cotoran more ef- replant only to cotton. Do not retreat. When properlyfective on cocklebur and applied, a preemergence application should not injuremorningglory. DCPA weak fall or spring seeded crops. However, prometryne labelon broadleaf weeds. warns against planting fall crop.Postemergenee Diuron+Surfactant 0.2 to 0.4 lb. Most annual broadleaved Apply as a directed early postemergence spiiay befor;and grassy weeds less than weeds are over 2 in. tall. Make a second app icationPrometryne+Surfactant 0'5 to 0'6 lb' 2 in. tall. Norea-arsonate- needed. Use a directed spray only DO NOT SPRAY“Wan-ts‘mamm 1'0 ”0 2-0 ‘b- surfactant combination OVER TOP OF COTTON. Add surfactant according toNorea+DSMA or 0.8 to 1.2 lb. + more effective on larger manufacturers directions. Observe label precautions toMSMA+surfactant 1.5 to 2.0 weeds than other treat- reduce possibility of residual injury to following crops.DSMA or 1.0 to meats.1.75 lb. MSMA

DSMA+surfactant 2-3 lb. Annual broadleaved weeds Apply as a directed spray after cotton is at least 8MSMA+surfactant 2 lb. le- than 2 in. tall and in. tall but before broadleaved weeds are over 2 in.annual grasses less than tall & before annual grasses are more than 1 in. tall.1 in. tall. Some suppres- DO NOT SPRAY OVER TOP OF COTTON. A secondsion of perennials such as application is usually needed. Make secoud applicatioaJohnsongrass and Nut- 1 to 3 weeks after the first. Under adverse growingsedge. conditions (cool, dry) control may be poor.Add surfactant according to manufacturers direction.Some formulations already contain surfactant. Readlabels. DO NOT APPLY AFTER COTTON FIRSTBLOOMS. These materials will not give residual chem-ical control.Peanuts Vernolate 24% lb. Annual grassy weeds and PREPLANT: Incorporate 3 in. deep in soil im-Preplsnt or most hroadleaved wceds mediately after application. Use hooded power drivenPres-«genes plus suppression of nut- rotary tiller or tandem disc followed by drag barrow.sedge. Other perennialsnot controlled. Morning-glory, ragweed & cockle-bur somewhat resistant.Plant seeds not less than 2 in. deep.PREEMERGENCE: Incorporate 2 in. deep with powerdriven rotary cultivator with teeth separated over rowas for cultivation. Ground-driven rotary hos may beused on light soils. Do not cover seed too deeplyControl usually lasts 6 to 8 weeks plus late seasongrass control. Under some conditions temporary earlyseason stunting and “leaf-seal" may occur. Use DN-BPl early postemergence to increase broadleaf con-tro .

CHEMICAL WEED CONTROL IN FIELD CROPSCrop Chemical Rate/Acre‘ Weeds Controlled Precautions and Remarks

Peanuts (con’t.) Benefin 1.12 lb. Annual grassy weeds and Incorporate 2 to 3 in. deep immediately after applica-Preplant some broadleaved weeds tion. preferably with power-driven rotary cultivator.Broadleaf weed control Do not overapply. Should give long term annual grassgenerally weak. control. Use DNBP early postemergence to increasebroadleaf control.Benefin + 0.75 + Annual grassy weeds Incorporate 2 to 3 in. deep immediately after appli-Vernolate 1.5 lb. and some broadleaved cation, preferably with power-driven rotary culti-weeds. Broadleaf vator. Should give long-term grass control plus someweed control generally nutsedge suppression. Use DNBP early postemergenceweak. to increase broadleaf control.Diphenamid 2 to 3 lb. Annual grassy weeds and Apply as ground begins to crack as peanuts emerge.Cracking diphenamid some broadleaved weeds. May be applied up to 7 days after cracking butStage DNBP Cocklebur and morning- grasses over 2-leaf stage probably will not be con-1% lb. DNBP glory somewhat resistant. trolled. Shallow cultivation will not reduce effective-ness of diphenamid and will greatly improve results ifdrought occurs after application. Length of control isusually 5 to 7 weeks plus late season grass control.NPA 3 lb. NPA Many annual broadleaved Premixed material available as “Dyanap.” Apply just4- & grassy weeds. Cocklebur as ground begins to crack & before peanuts emerge.DNBP 1% lb. DNBP & morningglory control Efiectiveness of this treatment has been variable invariable. N. G. Control is usually 3 to 4 weeks under favorableconditions.

DNBP 6 lb. Many annual broadleaved Apply before peanuts emerge. Control usually last: 8(amine Belts) & grassy weeds. Cocklebur to 6 weeks under favorable conditions. Grasses areand morninsslory control resistant if larger than 2-leaf stage. Eflectiveness hasvariable. been variable in N. C.Early Post- DNBP 1 to 3 lb. in Young annual broadleaved Apply at the emergence or up until the peanut plantsemergence (amine salts) 30 to 40 gal. weeds are 1% to 2 in. in diameter. Will control emergingwater. broadleaf weeds up to 2 to 3 in. tall, but will not givelong time residual control. Some peanut foliage burnmay occur. especially if temperature and humidity arehigh. Treatment is very useful for controlling earlybroadleaved weeds that escape or are resistant to pre-vious herbicide treatments.Small grains- 2.4-D amine $5 lb. in 6 to Winter annual weeds such Spray 2,4-D when grain is 4 to 8 in. tall or after tiller-wheat, oats.and barley.

(a(J

10 gal. water. as ragged robin. mustard.vetch, blessed thistle, wildradish.% lb. Corn cockle and dock.ltolifilb. Wild garlic and w. onion.

ing but before jointing. Spraying small grain too youngor after jointing can result in reduced yields and un-even ripening. Seeding of lespedeza must be delayedtwo weeks following first good rain after treatment.Use production practices favorable to maximum cropcompetition.

I78 CHEMICAL WEED CONTROL IN FIELD CROPS (Cont‘d.)Crop Chemical Rate/Acre‘ Weeds Controlled Precautions and Remarks

Small Grain- dicamba 1,4 lb. Most winter annual broad- Apply to fall seeded wheat, oats, and barley im-wheat, oats, leaved weeds. med-iately after winter dormancy and before they beglgnand barley dicamba + 17;, lb. + 1/3 lb. Good control knawel, some to Jomt. Use suflic1ent water for 300d coverage. 0. . ’ _ - f - I: not graze treated areas or feed treated forage ormm“ 2 4 D “mm" $322} ° ch” weed “d threshings to livestock. READ LABEL.DNBP 1 to 1.5 1b. in Chickweed and henbit ' Apply DNBP to grain when 4 to 6 in. tall. the tem-(amine salts) 30-60 gal. water perature is above 60°F., and no rain is expected forabout 12 hrs.

Sorghum Propazine 2 to 3 lb. Many annual broadleaved Apply at planting or immediately after, before weedsPreemergence and grassy weeds. and sorghum emerge. Forage or grain may be usedfor any purpose.Atrazine 2 to 3 lb. Most annual broadleaved Apply premergence or after emergence of sorghum andPostemergence and grassy weeds. before weeds are 1% in. tall. Shallow incorporation35 to 1% in. may increase efiectiveness of weed con-trol, especially under dry conditions. Do not graze orfeed treated forage within 60 days of application. Grainmay be used for seed or feed. DO NOT USE PRE-EMERGENCE ON LIGHT SANDY SOIL.2,4-D amine 1,4 lb. Same weeds as for corn. Apply when sorghum is about 4 in. tall.1/3 to 1/2 lb. Same weeds as for corn. Apply up until sorghum is 12 in. tall. Sorghum is lessin 6 to 10 gal. tolerant to 2,4-D than corn. Use drop nozzles as soonwater. as possible.Nitrogen solution- Same weeds as for corn. Apply nitrogen solution 2,4-D mixture about 5 weeks2.4-1) after planting. Apply as discussed for corn in Ext.Folder No. 148, 1968.

Soybeans Trifluralin 1,4 to 1 lb. Annual grassy weeds and Incorporate into soil 2 to 3 in. deep immediately afterPreplanting Vernolate 2 to 2% lb. some broadleaved weeds. application.Cocklebur & morningglory Under certain conditions temporary early season stunt-resistant. Ragweed & ing may occur. Materials not effective in high organicsicklepod resistant to tri- matter soils in eastern part of state. ’5 to ‘56. lb.fluralin. Vernolate gives trifluralin is adequate for Coastal Plain.nutsedge suppression.Preplanting Nitralin 17$ to 1 lb. Annual grassy weeds and Incorporate 1 to 1% in. deep within 2 hrs. after appli-. or some broadleaved weeds. cation. Under certain conditions, temporary early-Preemergence Cocklebur, morningglory, season stunting may occur. Not effective in highand ragweed resistant. organic matter soils. If preplant treatment is usedextreme care must be used when planting not to turnup untreated soil. If premergence treatment is used,incorporation must not disturb seed or cover too deeply.

QZ

CHEMICAL WEED CONTROL IN FIELD CROPS (Cont'd.)Soybeans (con’t.) Amiben 2 to 3 lb.DNBP 6 to 9 lb.(amine salts)Linuron 1.0 to 1.25 lb.

Many annual broadleavedand grassy weeds. Cockle-bur & morningglory gen-erally resistant.These treatments have generally given variable resultsin N. C. Three to six weeks weed control may beexpected under favorable conditions. Materials not ef-fective in high organic matter soils in eastern part ofstate, although amiben has performed better than theother herbicides. Use linuron in Piedmont section ofstate only on clay and clay loam soils. Do not plantbeans in furrow. Injury may occur after preemergenceuse of linuron after unusually heavy rain. Some rain.fall after application is necessary for activation. Ifdrought occurs use shallow rotary hoeing.Postemergence Apply postemergence to soybeans and before weedsare over 2 in. tall. Add surfactant according to manu-facturer’s directions. Moderate to severe foliage burnto beans when sprayed over-top, but has not reducedyields. Semi-directed spray preferred—better coverageof weeds with less foliage burn. Especially useful tokill weeds that escape or are resistant to earlier preplant or preemergence treatment.Apply 7 to 10 days before bloom up to mid-bloom insoybean fields with severe cocklebur infestation. Do notapply earlier unless weeds seriously threaten beanstand. If applied after mid-bloom period do not harvestwithin 60 days of application. Temporary twisting ofbeans does not indicate permanent injury.Tobacco Apply broadcast overtop the tobacco immediately aftertransplanting. Use sprayer equipped to apply wettablepowders. Two shallow cultivations (2”) are suggested.the ones that are normally the second and lay-by culti-vations. Rainfall or irrigation after application isneeded for effectiveness. If it does not rain within 10to 12 days after application, cultivate shallow or ir-rigate. Some damage to small grain planted in fall mayoccur unless band treatment is used.

NPA + DNBP 3 lb. NPA +1% lb. DNBP

Chloroxuron 10 to Most annual broadleaf15 lb. weeds. Poor to no controlof annual grasses. Sickle-pod and sida somewhatresistant if over 1 in tall.

2,4-DB 0.2 to 0.25 lb. Cocklebur, partial controlof morningglory.

Diphenamid 4 lb. Annual grassy weeds andsome broadleaved weeds.

Pebulate 4 lb. Annual grassy weeds andsome broadleaved weedsplus suppression of nut-sedge.Benefin 1.12 to 1.5 lb. Annual grassy weeds andsome broadleaved weeds.

Apply after beds are formed but before tobacco ' set.Mix 2-3" deep in top of bed with a power-tilted!driven rotary hoe. Use equipment with short tines overrow, longer ones toward middle. Tines should be closeenough together to give thorough incorporation. Twoshallow cultivations are suggested, the ones that arenormally the second and lay-by cultivations.' Based on pounds active ingredient or acid equivalent per acre on a broadcast basis.width of band and row spacing. The following formula is useful:

band width in inchesrow width in inches

USE CHEMICALS SAFELY — FOLLOW LABEL DIRECTIONS

For band treatment reduce rate proportionately according to

X recommended broadcast rate 2 amount to apply per acre on band.

CHEMICAL WEED CONTROL IN VEGETABLE CROPSWALTER A. SKROCH and T. J. MONACO. Horticultural Science Dept.

Crop Chemical Rate“ Weeds Controlled Precautions & RemarksAsparagus Simazine 2 to 4 lb. Annual broadleaved Apply to clean soil in springand grassy weeds. to established asparagusprior to weed and spearemergence. A second appli-cation may be used afterharvest after removing weedgrowth.

Monuron 1 to 2 lb. Most annual broad- Apply before weed emergenceleaved and grassy and up to first cutting in es-weeds. tablished asparagus. Makesecond application imme-diately after harvest ifneeded.Petroleum 40 gal. Small annual broad- Preemergence applicationSolvents leaved and grassy when weeds are 1-2 in. high.(varsol, weeds.stoddaé'd 100 gal. Small annual broad- Post-harvest application toso ven 5) leaved and grassy soil. Do not apply to ferns.weeds.Dalapon 8.5 to 15 lb. Quackgrass Apply 8.5 lb./A before cut-ting and again 3 to 4 weekslater as needed. For singletreatment, use 15 lb./Aeither before or after cut-ting season.Bermudagrass Use 15 lb./A during or aftercutting season, and a. secondspray of 8.5 lb. as needed.NOTE: During the cuttingseason, spray immediatelyafter cutting. Direct latersprays under fern growth.

Beans Trifluralin 1%; to 1 lb. Annual grasses & Apply preplanting and in-(Dry) some broadleaved corporate into soil 2 to 3 in.weeds. deep. Incorporate by cross-disking or with power-drivenrotary cultivator. 1/2 lb. ade-»—. «mate for Coastal Plain.Amiben 2 to 3 lb. Most annual broad- Apply preemergence as soonleaved & grassy after planting as possible.weeds.DNBP 6 lb. Most annual broad- Preemergence application.(amine leaved & grassy Do not use on very light,salts) weeds. sandy soils. Results general-

}_ ly variable.DNBP 3 to 4 lb. Most annual broad- Apply during emergence(amine leaved & grassy when beans are in, but notsalts) weeds. beyond “crook” stage. Thistreatment especially usefulfor young broadleaf weedcontrol.

Beans Trifluralin V; to 9% 1b. Annual grasses & Apply preplanting and in-(Liml) some annual brnad- corporate immediately intoleaved weeds soil 2 to 3 in. deep. Incor-porate by cross-disking or apower-driven rotary culti-vator.

Amiben 2 to 4 lb. Most annual broad- Apply preemergence a9 soonleaved and grassy after planting as poss:ble.weeds.DNBP 6 lbs. Most annual broad- Preemergence application.(amine leaved and grassy Do not use on very lightsalts) weeds. sandy soils. Results general-ly variable.

26

CHEMICAL WEED CONTROL IN VEGETABLE CROPS (Continued)Crop Chemical Rate" Weeds Controlled Precautions & Remarks

DNBP 3 to 4 lb. Most annual broad- Apply during emergence(amine leaved & 81‘8853’ when beans are in. but notsaltS) weeds. beyond ‘crook” stage. Thistreatment especially usefulfor young broadleaf weedcontrol.Beam Trifluralin 17$ to 3/4 lb. Annual grasses and Apply preplanting and in-(Snap or some annual broad- corporate immediately intoPole) leaved weeds. soil 2 to 3 in. deep. Incor-porate by cross-disking orwith power-driven rotary,cultivator.

EPTC 2 to 3 lb. Annual grassy Apply preplanting and in-weeds and most corporate immediately intobroadleaved plus soil 2 to 4 in. deep.suppression ofnutsedge.DNBP 6 lb. Most annual broad- Preemergence application.(amine- leaved and grassy Do not use on very light,salts) weeds. sandy soils. Results general—ly variable.DNBP 3 to 4 lb. Most annual broad- Apply during emergenceleaved and grassy when beans are in. but notweeds. beyond “crook” stage. Thistreatment especially usefulfor young broadleaf weedcontrol.Cabbage Trifluralin 1/; to 1 lb. Annual grasses Use on transplants on1y_and some annual Apply preplant and incor-broadleaved weeds. porate into soil immediately.% to 34 1b. generally ade-quate.DCPA 8 to 10 lb. Most annual grasses Apply to clean soil at timeand some broad- of seeding or immediatelyweeds. after transplanting. May beapplied over top of trans-plants.TOK 3 to 6 lb. Annual grass and Apply a single applicationsome broadleaved just after seeding the cropweeds. or make a single applica-tion one week after cropemerges or transplanting.Trial use only.

Carrots Petroleum 20 to 100 gal. Annual broadleaved Preemergence application.Solvents and grassy weeds. Apply before weeds are 3 m.(Varsol, tall as a wetting spray.Stoddard 100 to 150 gal. Annual broadleaved Postemergence application.Solvents) and grassy weeds. Apply at 2 to 4 leaf stageand repeat as needed untilcarrot root is 1/; in. in dia-meter. Do not apply laterthan 6 weeks prior to har-vest.Linuron 1 to 2 lb. Most annual broad- Trail use only. Preemergenceleaved and grassy application or postemergenceweeds. application when carrotsare 2 to 6 in. tall.

Corn Atrazine 2 lb. Annual grassy & Apply preemergence 02‘ as(Sweet) broadleaved an early postemergence over-weeds. top until weeds are 1% in.tall.Simazine 2 lb. Annual grassy and Apply preemergence.broadleaved weeds.2. 4-D 1/4 lb. Young annual broad- Apply overtop from emer-leaved weeds. gence until corn is 5 to 6 in.tall.

17$ 11) Young annual broad- Directed spray up to tas-leaved weeds. seling of corn.

27

CHEMICAL WEED CONTROL IN VEGETABLE CROPS (Continued)Precautions 8; RemarksCrop Chemical Rate‘ Weeds Controlled

Linuron 2 1b. Young annual broad- Postemergence applicationleaved and grassy as a directed spray whenweeds. corn is 15 in. tall or taller.Do not apply within 60 daysof harvest.Greens DCPA 6 to 10 lb. Annual grass & Apply immediately after(collards, Kale, some broadleaved seeding preemergent to themustard and weeds. weeds and crop.turnip greensor roots)Okra Trifluralin % to 1 lb. Annual grasses & Apply preplant and incor-some broadleaved porate into soil immediately.weeds. Do not apply after planting.

Diphenamid 4 to 6 lb. Annual grasses & Apply immediately aftersome broadleaved planting.weeds.Peas DNBP 6 lb. Most annual broad- Preemergence application.(Green) (amine leaved & grassy Results generally variable.salts) weeds.2.25 lb. Young annual broad- Postemergence applicationleaved weeds. when peas are 2 to 6 in. tall.Do not apply after flowerbuds are visible.Peas Trifluralin 1,5 to 1 1b. Annual grasses & Apply preplant & incor-(Southern) some broadleaved porate 2 to 3 in. into soilweeds. immediately. 35 to 55/4 lb.generally adequate.DNBP 6 lb. Most annual broad- Preemergence application.leaved & grassy Results generally variable.weeds.2.25 lb. Young annual broad- Postemergence applicationleaved weeds. when peas are 2 to 6 in. tall.Do not apply after flowerbuds are visible.Peppers Trifluralin 1743 to 1 lb. Most annual grassy Apply pretransplanting andand some broad- incorporate into soil im-leaved weeds. mediately. 1A; to % lb. gen-erally adequate.Diphenamid 4 t0 6 lb- Annual grassy and Apply broadcast over-top ofsome broadleaved transplants at or within 30weedS. days after transplanting. Ifapplication is delayed, cul-tivate to destroy existingweed growth before spray-ing. Shallow cultivation (2in.) will not reduce effective-ness of chemical.

DCPA 8 to 10 lb. Most annual grasses Apply immediately or up toand some broad- 6 weeks after transplanting,leaved weeds. cultivate to destroy existingweed growth before spray-ing. Shallow incorporation(1 to 2 in.) may improveeffectiveness especially ifdrought follows application.Amiben 3 to 4 lb. Annual grassy and Use Granular only. Applybroadleaved weeds. immediately after or within30 days of transplanting toweed free soil.Potatoes Diphenamid 4 to 6 lb. Most annual grasses Apply at planting or im-(Irish) and some broad- mediately after.leaved weeds.DCPA 8 to 10 lb. Most annual broad- Apply at planting or im-leaved and grassy mediately after.weeds.EPTC 3 to 4 lb. Annual grassy weeds Apply preplant and incor-and most broad-leaved weeds plusnutsedge suppression.

porate into soil immediatelyby cross-disking or withpower-driven rotary cultiva-tor.28

CHEMICAL WEED CONTROL IN VEGETABLE CROPS (Continued)Crop Chemical Rate“ Weeds Controlled Precautions & Remarks

Potatoes Diphenamid 4 to 6 lb. Annual grasses and Apply as a band treatment(Sweet) some broadleaved over the row immediatelyweeds. after transplanting. Culti-vate the middles as needed.Amiben 3 to 4 lb. Most annual broad- Apply as a band treatmentleaved and grassy over the row immediatelyweeds. after transplanting. Culti-vate the middles as needed.DCPA 8 to 10 lb. Most annual grassy Apply as a band treatmentand some broad- over the row immediatelyleaved weeds. after transplanting. Culti-vate the middles as needed.Vernolate 2 lb. Annual broadleaved Apply broadcast and incor-and grassy weed porate immediately with aplus nutsedge sup- disk 4 to 6 inches deep priorpression. to bedding. Bed as is nor-mally done and plant im-mediately if desiifbd.Tomatoes Diphenamid 4 to 6 lb. Annual grassy Apply broadcast over-top of(transplanted) and some broad- tomato plants immediatelyleaved weeds. or within 30 days aftertransplanting. If applicationis delayed, cultivate to des-troy existing weed growthbefore spraying. Shallowcultivate as needed.Trifluralin 17$ to 1 lb. Annual grass and Apply pretransplanting andsome broadleaved incorporate into soil 2-3 in.weeds. deep immediately.Pebulate 3 to 4 1b. Most annual grassy Preplant soil application, in-(PEBC) weeds and some corporate immediately 2 tobroadleaved weeds 4 in. deep. Set transplantsplus suppression of immediately. May also benutsedse. applied as a directed sprayafter transplanting and in-corporated imemdiately. Donot apply after fruit beginsto form.

Amiben 3 to 4 lb. Many annual broad- Use granular material only(granular leaved and grassy as liquid will burn theonly) weeds. foliage. Available as “Veg:-ben”. Apply immediatelyafter transplanting up tolayby to weed-free soil.. . . . te‘ R te based on active ingredient and broadcast basm per acre. For band treatment reduce. broadcast rapfoportionately according to width of band and row spacing. The followmg formula is useful.band width in inchesrow width in inches X recommended broadcast rate = amount to apply per acreon band

29

CHEMICAL WEED CONTROL IN FRUIT CROPSWALTER A. SKROCH and T. J. MONACO, Horticultural Science Dept.

Crop Chemical Rate/acre’ Weeds Controlled Precautions & RemarksBlueberries Simazine 4 lb. Annual broadleaved Apply half he maximum an-Raspbérfie. and grassy weeds. nual application in the springTrailing before buds break and weedBlackberries emergence and half after har-vest.Strawberries Sesone 2 to 4 lb. Most annual broad- Apply to first year plantingsleaved and some after plants are well establishedannual grassy weeds. and monthly thereafter follow-ing cultivation. Avoid applica-tion when first runner plants arerooting. 0RApply to established plantingsbefore blossoming and afterpicking following each cultiva-tion. Do not apply within 7 daysor during harvest season. Re-sults are generally variable.DCPA 6 to 9 lb. Most annual grass Apply preemergence to weedsand some broad- and repeat if nrcessary but notleaved weeds. more than 3 applications shouldbe applied any one year.Diphenamid 4 to 6 lb. Annual grass and It has long residual in soil.some broadleaved Apply to non-bearing plants atweeds. least 12 months prior to har-vest. On sandy soil apply 2 lbs.at planting and 2 lbs. in mid-April. 0n heavy soils apply 8lbs. at planting and 3 lbs. inmid-April.2,4-D Amine 1%) 1b. Annual broadleaved Apply to well established straw-weeds. berries after harvest and beforerunners form. Not more than 2treatments per year. Do notapply during bud, flower orfruit stage. Timing is very criti-cal to avoid damage.DNBP 3 lb. Winter annual Use only while strawberries are(Dinitro) weeds. dormant (late Nov. through(Amine salt) Jan.) Temperatures should beabove 50°F. Include wettingagents (2 qts. per 100 gal. spraywivtnre) and apply at least 30gal. of spray per acre.

Chloroxuron 3 or 4 1b, Most annual Apply over the top as a broad-broad-leaves cast or band treatment to es-and some grassy tablished plants free of weedweeds anytime except during the in-terval 60 days prior to har-vest. Apply no more than 2applications per year.Apples Simazine 4 lb. Annual broadleaved Apply preemergence to weedsand grassy weeds. under trees which have beenestablished 1 year or more.Simazine plus 3 + 1 lb. Annual broadleaved Use 7 lb. Amizine/IOO gal.Amitrole and grassy weeds water. Wet weeds thoroughly—(Amizine) plus suppression use about 21/2 gals. of spray perof woody perennials. 1000 sq. ft. Treat a band atleast 3 ft. wide under thetrees. Apply after weeds emergebut before fruit starts to form.Diuron 3 lb. Annual grassy and Apply in early spring to treessome broadleaved not less than 4 years old.weeds.Amitrole 2.0 lb. Poison ivy Apply before fruit forms 01'after picking. Do not spraystems. foliage, or trunks offruit trees.

30

CHEMICAL WEED CONTROL IN FRUIT CROPS (Can't)

Crop Chemical Rate/acre' Weeds Controlled Precautions & RemarksApples(can't) Dalapon 5to7lb. Perennial grassu. Apply around trees over 4 yearsold. Apply when grass is 4 to 6inches high. Make a second ap-plication 2 weeks later. Use 1lb. in 16 gal. water. Spray towet foliage. Add wetting agentat 2-3 pts. per 100 gal. spray.Dichlobenil 6 lb. Annual and peren-nial grass and broad-leaved weeds.

G-4 is a 4% granular materialwhich is far superior to thewettable powder. Apply to anyage tree in Jan. or Feb.Ammoniumsulfamate 54 lbs./100gals. water Poison ivy Apply as a wetting spray topoison ivy in full leaf. Keepspray of! tree foliage and fruit.Paraquat 0.5 to 1.0 lb. Contact kill of allgreen foliage Non-bearing only. Apply whengrass and weeds are 1 to 6inches high and succulent forbest results. Direct spray withlow pressure to avoid contactwith tree foliage or bark leuthan one year old. Add wet-ting agent to make 0.25% byvolume f0 spray for best re-sults.Terbacil 1.6 to 3.2 lb. Most annual broad-leaved and grassyweeds plus manyperennial grasses.Trial use only. Use only ontrees that have been established3 years or more. Do not useon light sand or eroded gravel-ly soils. Apply when new weedgrowth is 1 to 2 inches high.Peaches Dalapon 5 to 7 lb. Bermudagraas Apply to actively growing grassthe year prior to planting trees.Repeat application in 10-14 daysis advantageous.Dichlobenil 6 lb. Annual and peren-nial grass and weeds. G-4 is a 4% granular materialwhich is far superior to thewettable powder. Apply to anyage tree in Jan. or Feb.Dalapon Bermudagrass Use 1 lb. in 15 gal. water andapply the solution to wet thegrass. Avoid spraying the foli-age of the tree. Use only ontrees established 4 years ormore. Do not apply within 30gays of harvest. Repeat in 10-14aya.

Simazine 2to4lb. Annual broadleavedand grassy weeds. Apply in early spring prior toweed emergence. Use only ontrees established 4 years ormore. Caution: Use on lightsandy soils may injure tree.Paraquat 0.5 to 1.0 lb. Contact kill ofall green foliage Non-bearing only. Apply whengrass and weeds are 1 to 6 in-ches high and succulent forbest results. Direct spray withlow pressure to avoid contactwith tree foliage or bark lessthan one year old. Add wettingagent to make 0.25% by vol-ume of spray for best results.Caution: It is very difficult tospray first year trees withoutinjury.Terbacil 1.6 to 3.2 lb. Most annual broad-leaved and grassyweeds plus manyperennial grasses.Trial use only. Use only ontrees that have been establish-ed 3 years or more. Do not useon light sand or eroded gravel-1y soils. Apply when new wgrowth is 1 to 2 inches high.

31

CHEMICAL WEED CONTROL IN FRUIT CROPS (continued)Rate/acre" Weeds Controlled Precautions & Remarks4 lb. Annual broadleavedand grassy weeds. Apply half the maximum an-nual application in the springbefore buds break and weedemergence and half after har-vest. Do not apply in vineyardsless than 3 years old.2 to 3 lb. Annual grassy andsome broadleavedweeds.

Apply prior to germination ofannual weeds. Vineyards shouldbe at least 3 years old.

Crop ChemicalGrapes Simazine

DiuronParaquat 0.5 to 1.0 lb. Contact kill ofall green foilage. Non-bearing only. Apply whengrass and weeds are 1 to 6 inch-es high and succulent for bestresults. Direct spray with lowpressure to avoid contact withfoliage or bark less than oneyear old. Add wetting agent tomake 0.25% by volume of sprayfor best results.

‘ Rate based on active ingredient and broadcast basis per acre. For band treatment of row fruit crops.reduce rate proportionately according to width of band and row spacing. The following formula is useful:band width in inchesrow width in inches

32

X recommended broadcast = amount to apply per acre in band

CHEMICAL WEED CONTROL IN WOODY ORNAMENTALSWALTER A. SKROCH, Horticultural Science Department

Treatmentand Place Chemical Bate‘ WeedsControlled RemarksPreplantIn NurseryBeds

MethylBromide 1-3 lb./100sq. ft. Most, except hard-seeded legumes andsome deep rootedperennialsTill beds to a depth of at least8". Soil temperature should beabove 60°F. Cover area withplastic for at least 24 hrs. duringfumigation. Remove cover andwait at least 3 days to 2 weeksbefore planting. Warm tempera-ture with no rains permits earlieruse of soil after fumigation.DMTT 1-2 qt./100 sq. ft. same as above As above. Applied mixed withwater. Water seal can be used inplace of plastic cover, however,results better with cover. Wait atleast 1 to 4 wks. after treatmentto plant.SMDC 1-2 lb.100 SQ. ft. same as above As above for DMTT.

Preplantln Fields EPTC 5-10 lbs. Annuals, mugwortwild artemisia, quack-grassPrepare soil by plowing in fall.Apply herbicide and incorporateinto soil immediately. Do notplant until late spring.

Dichlobenil 4-10 lb. Annuals, wildartemisia, Canadathistle, nutgrass,wild artichoke orFlorida betony,alligator weed &most perennials

Prepare soil by plowing in fall.Apply herbicide over surface. In-corporation to a depth of 1 to 2"is especially beneficial if soils aredry when application is made.Planting can be started about 4wks. after herbicide applicationwith container grown plants. Ap-ply in late September throughNovember.Dalapon 10-15 lb. Quackgrass Cut grass down with mower andafter new growth is about 10"tall apply herbicide. Plow about10 days later. Can be used to con-trol Bermudagrass. Use as a di-rectional spray.Trifluralin 1-2 lbs. Annuals Plow field and prepare as forplanting. Must incorporate her-bicide immediately after applica-tion. Planting should be delayed atleast 2 weeks for container grownpants. Best when applied earlyspring or late fall.Preemergeneeto WeedslnEstablishedStock toSoil"

DCPA 10-15 lb. Annual grassesmainly Wide tolerance among crops. Poorcontrol of broadleaved weeds. Pre-emergent to weeds necessary forcontrol.Dichlobenil Annuals and manyperennials Wide tolerance among plants in-cluding azaleas, boxwoods, hy-brid rhododendron, gardenias,some hollies, leucothoe, pieris,pyracantha, Viburnum and manyothers. Do not use on fir. Somepost-emergence action mainly pre-emergent to weeds. Heavier ratefor late fall & early winter ap-plications. During growing season.do not exceed the 4 lb./A rate.Light incorporation assures betterweed control.Diphenamid 4-8 Annuals Wide tolerance among plants in-cluding azaleas, boxwood, camel-lias, most hollies, osmanthus, pit-tosporum, privet, plums, etc. Pre-emergent to weeds.

33

CHEMICAL WEED CONTROL IN WOODY ORNAMENTALS (Col-It’d.)

Chemical Rate‘ WeedsControlled RemarksCIPC 6-10 Annuals Effective only when soil tempera-tures are low, 50°F. or lower.Very effective against chickweedsfall and early spring grasses. Pre-emergent and some post emer-gence action.Simazine 2-3 Annuals andmany perennials Excellent weed control. Injury hasbeen observed on azaleas, Jap-anese holly, euonymous, lilac,pittosporum, mockorange and priv-ets. Pre and post emergence actionmainly small weeds. Rhododen-drons, mountain laurel. most nar-row leaf evergreens. shade treesand many others are tolerant.Trifluralin Annuals Must incorporate immediately intothe soil for good results. Ratherwide tolerance among plants. Pre-emergent action mainly.

‘ Rates are in pounds of active ingredient per acre except where noted differently.” Clean cultivation before applying herbicides assures better weed control.

CHEMICAL WEED CONTROL IN FLORAL CROPSJ. M. JENKINS, Castle Haynes Research Station,W. A. SKROCH and T. J. MONACO, Horticultural Science Dept.

Crop or Plant Chemical Rate/Acre Weeds Controlled Precautions and RemarksGladiolus Diuron 1 lb. Many annual grassy Apply after planting prior toand broadleaved emergence. Cultivate before treat-weeds. ment if small weeds are present.

Trifluralin 1-1.6 lb. Most annual grassy Apply immediately after theweeds and some corms have been planted. Incor-broadleaved weeds. porate trifluralin 1 to 2 inchesdeep immediately after applica-tion.2,4-D 0.5 to 1.0 lb. Some annual grassy Caution: Use amine form only.and broadleaved Apply as a directed spray to baseweeds of gladiolus at least 12 inches‘ high but prior to spiking.

34

CHEMICAL WEED CONTROL IN LAWNS AND TURFW. M. LEWIS, Crop Science Department

Weed Chemical Rate/Acre' Weeds Controlled Precautions and RemarksCrabgrul Terbutol 12 lb. Smooth and hairy All established turfgrasses are tolerantpreememnce" crabgrass, foxtails, and except bentgrass greens.other annual grasses.Benefin 2 lb. Safe to apply to all established turfgrassesexcept bentgrass. Do not apply to lawnsseeded the previous fall.Benaulide 12% lb. May be applied to all established turf-grasses and dichondra.DCPA 121b, ' May be applied to all established turf-grassesSiduron 10 lb. Use only on bluegrass, fescue, and certainbentgrasses (check label). Can be used atthe rate of 8 lbs. when seeding bentgrass,bluegrass, fescue, and ryegrass. Do not useon bermudagrass carpetgrass, or centipede—grass.Crabgrass CMA 21,9 gal. Crabgrass, dallis. May be used on bentgrass, bermudagrass,postemergenee ( 10.3%) grass, and goose- bluegrass, fescue, and zoysia. Begin treat-graas. ment when weedy grasses are young (3-5leaf stage). Use 2 applications 7-10 daysapart. More mature plants may requireadditional applications. Spray when soilmoisture is good and air temperature is_ 80°F. or above.DSMA 3to4lb. Bluegrass, bermudagrass, and zoysia are63% tolerant. Bentgrasses and fescues slightlysensitive. Apply as above.MAMA 2% gal. Use on bluegrass, bermudagrass, fescue,416%) and zoysia. Do not use on bentgrass. Applyas above.MSMA 5 cups of51%9cupsof 35%Bundles! 2.4-D 1 lb. Dandelion, carpetweed, Cut rate one-half for bentgrass. carpet-amine Carolina cranesbill, grass, centipedegrass, and St. Augustine-; curly dock, plantain, grass. Spray when weeds are young andponyfoot, shepherds- are actively growing. To reduce danger ofpurse, and yellow injury to flowers and ornamentals by sprayrocket. drift, use low pressure and do not sprayon windy days.Silvex 1 “3- Common ChiCRWGQd. Observe same precautions as for 2,4-D.mouseear chickweed,creeping charlie orground ivy, dandelion,henbit, knawel, blackmedic, pennywort,spotted spurge, whiteclover, wild straw-berry, yellow wood-sorrel, and commonyarrow.iDicamba 174% lb. Chickweed, white Apply as foliar spray to growing weeds.‘ clover, curly dock, Prevent injury to ornamentals. Avoid root-henbit, knotweed, ing zone of shallow rooted trees andred sorrel. shrubs.Nutaedge 2,4-D 1 lb. Nutsedge Apply when nutsedge first appears inamine spring. Repeat as it reappears, usuallymonthly for 3 to 4 treatments. Use onwell established lawns of bluegrass, fescue,common bermudagrass, or zoysia.MAMA 5 gal., Make 3 to 4 applications at monthly(16%) intervals starting in June. Use on bermuda-and zoysia.

35

CHEMICAL WEED CONTROL IN LAWNS AND TURF (Cont’dJWeed Chemical Rate/Acre‘ Weeds Controlled Precautions and RemarksNutsedze DSMA 3 m 4 1b Several applications at 10-14 day intervals(con't.) 63% needed. Use on bermuda grass, bluegrass,fescue and zoysia.MSMA 5 cups of51%9cupsof 35%Wild garlic or 2.4-D 3 lb. Wild garlic or Apply late February or early March. Addwild onion amine wild onion a wetting agent to keep spray frombouncing off garlic leaves. Repeat treat-ment for 2 years. Avoid spray drift thatcan injure susceptible plants. Use on blue-grass, fescue, common bermudagrass, orzoysia, For more susceptible grasses, usespot treatment below.2.4-0 1 tbs. of Apply December to April. Use as spotamine 1% 2,4-D/ treatment for widely scattered clumps inclump or small areas. This treatment will killgarlic grasses in an area about 4 in. across. Turfuse preS- grasses fill in bare sports with a season'ssurized ap- growth.plicator° Based on pounds active ingredient or acid equivalent.‘° Granular formulations generally more eflective than liquid or wettable powders. When spraying wet-table powders or liquid formulations, follow with at least 1/6 inch of water—irrigation or rainfall.Apply by March 10 in Southern Coastal Plains, March 26 in Northern Coastal Plains and Piedmont.and April 10 in Mountains.

THE MOST EFFECTIVE PESTICIDE MAY BE USELESSWITHOUT PROPER APPLICATION

THINK! IS THIS THE PROPER DOSAGE?READ! WHAT DOES THE LABEL SAY?

36

KEEP PESTICIDES IN PROPERLY LABELED CONTAINERS

"Read the Label”

L8

CHEMICAL CONTROL OF SPECIFIC WEEDSA. D. WORSHAM. W. M. LEWIS. and W. A. SKROCH

Weed Chemical Rate‘ Time to Spray Precautions and RemarksArticnoke Dichlobenil 4-10 lb/a Any time. Fall DO NOT USE ON CROP LAND. See Precau-betony or or winter best. tions and Remarks under Weed Control inFlorida betony Woody Ornamentals.Bermudagrau Dalapon 5 to 7 lb./ acre Any time during growing This treatment is only effective when the grassin 30 to 60 gal. season when grass foliage is actively growing. In an old sod the areawater is young (4 to 6 in. high). should be tilled and the regrowth treated whenRepeat at 10 to 20 day it is 4-6 inches high. The area should not be dis-intervals for 2 to 3 appli— turbed for 3 days after treatment but tillagecations. after this period will improve control and hastenthe dissipation of the herbicide. Wait 3 weeksbefore planting susceptible crops. For spot treat-ment use 1 lb. per 10 gal. of water and spray towet the foliage. The addition of %% of a deter-gent or wetting agent increases the effectiveness.Sodium TCA 75 to 100 lb./ During growing season This rate will sterilize soil for 6 to 9 weeks dur-acre in 30 to ing summer months.100 gal. waterSodium chlorate 1% to 2 lb./ During growing season Use as solid granules for spot treatment. This rate100 sq. ft. will sterilize soil for 6 to 9 months.Johnsongrass Dalapon 5 to 7 lb. in 30 Any time during growing Same as bermudagrass except Johnsongrass shouldto 60 gal. water. season when grass foliage be 8-16 inches tall when treated. Repeat at 10 tois young (8 to 16 in. high) 20 day intervals for 2 to 3 applications.DSMA or MSMA 2 lb. per 40 gal. Any time during growing Spray when air temperature is 70°F. or above.water or 3 to 4 season when grass is grow- Add surfactant at ]75% v/v if not already in for-Ib./acre. ing vigorously. mulation. 4 to 5 treatments needed for completekill.Sodium TCA 100 to 125 lb. During growing season. This rate will sterilize soil for 6 to 9 weeks dur-per acre in 30 ing summer months.to 100 galwater.Sodium chlorate 1% to 2 lb. During growing season. Use as solid granules for spot treatment. Thisper 100 sq. ft. rate will sterilize soil for 6 to 9 months.Kudzu 2,4.5—T 12 to 18 lb. per May 15 to June 15. Ester form is more eflective. Use eater only if no300 gal water. susceptible crops are nearby. Retreatment at 6-week intervals will be necessary. 2,4-D + 2,4,5-Tmixtures will work but not quite as efl'ectively.Mugwort EPTC 6 lb./acre Spring or fall(Artemisia vulgaris) Plow area prior to treatment. Incorporate chem-ical into soil immediately after application. Roto-tilling is the preferred method but deep cross-disking is satisfactory. Treatment most effectivewhen soil is moist but not wet. Under normalconditions the herbicide will be dissipated in 8-12weeks. Tilling the soil several times prior toplanting will help dissipate chemical from soil.’ Based on pounds active ingredient or acid equivalent.

88

CHEMICAL CONTROL OF SPECIFIC WEEDS (Cont'd.)Weed Chemical Rate” Time to Spray Precautions and RemarksMugwort (con’t.) Dichlobenil 4 to 101b/A Any time. Fall DO NOT USE ON CROP LAND. See Precau-or winter best. tions and Remarks under Weed Control inWoody Ornamentals.Nutsedge* 2.4-D 1 lb./acre Early in .growing season Corn crop can be produced while using 2,4-D.“Nutgran" following a thorough disk- Apply pre—emergence rate. Follow 3 to 4 weeksing. Repeat at 3-week in- later with rate suggested for corn and repeat.tervals for 3 treatments. Rate suggested can be used following tobaccoharvest.Sodium chlorate 11/3 to 2 lb. During growing season. Use as solid granules for spot treatment. Thisper 100 sq. ft. rate will sterilize soil for 6 to 9 months.EPTC 6 lb./acre Any time after existing Must be immediately mixed into soil after spray-stands of nutsedge have ing. Use deep cross-disking or roto tilling. Willbeen destroyed by tillage. suppress nutsedge sprouting for 8 to 12 weeks.Follow only with tolerant crops for which labelclearance has been granted.

Dichlobenil 4-10 lb./A Any time. Fall DO NOT USE ON CROP LAND. See Precautionsor winter best. and Remarks under Weed Control in WoodyOrnamentals.Poison ivy and 2,4-D 2 to 3 lb./100 Apply in late spring or Apply only to plant material to be killed. ApplyPoison oak Amitrole gal. of water early summer when the as a wetting spray. Avoid drift. Repeat in 6 toplants are growing rapidly. 8 weeks if needed.Quackgrau Dalapon 15 lb./acre Early fall Same as bermudagrass except quackgrass should6-10 lb./acre Early spring. be 6-12 inches tall when treated.in 30 to 60gal. water.Atrazine 3 to 4 Ib./acre Fall or spring. For single application use 3 to 4 lb./acre in fallor 2 t 03 weeks before plowing in spring. Leaveland undisturbed until just prior to prepara-tion for spring planting of corn. For split ap-plication, use 2 lb./acre in fall or spring asabove followed with 2 1b./acre at planting.Sodium TCA 60-75 lb. in During growing season.40—60 gal. water This rate will sterilize soil for 6 to 9 weeks dur-ing summer months.Sodium chlorate 11/; to 2 lb.per 100 sq. ft. During growing season. Use as solid granules for spot treatment. Thisrate will sterilize soil for 6 to 9 months.‘For nutsedge suppression in crops see weed control for specific crop.N Based on pounds active ingredient or acid equivalent.

STOP! Read the Label!

Crop Treated

HERBICIDE USAGE INFORMATION—1968

Acres Herbicide Amount Used Cost

39

Crop Treated

HERBICIDE USAGE INFORMATION—1968

Acres Herbicide Amount Used Cost

4O

IMPORTANT NOTICE TO USERS OFPESTICIDE MANUAL

All pesticides and usages mentioned in this Manual conform to thosecurrently registered with the Pesticides Regulation Division, USDA.However, after December 31, 1967, registration under the Federal In-secticide, Fungicide, and Rodenticide Act for pesticide products now reg-istered for use in a manner involving food or feed on a “no residue” or“zero tolerance” basis will be cancelled unless: (1) finite tolerances orexemptions from the requirement of tolerances have been established bythe Food and Drug Administration, or (2) progress reports have beensubmitted to the Pesticides Regulation Division showing that studies arebeing conducted to obtain data to support finite tolerances.

If cancellations do occur, personnel at North Carolina State Universitywill attempt to notify users of the Pesticide Manual. However, everyoneusing, recommending, or selling pesticides should keep himself abreastof registration changes.

IN CASE OF POISONINGThere are 7 Poison Control Centers in North Carolina, as shown below:

NORTH CAROLINAAsheville Poison Control Center 252-5331 Mary Helen McConnell, M.D.

Memorial Mission Hosp. Ext. 261509 Biltmore Ave.

Charlotte Poison Control Center EDison 4-6831 R. T- Lucas, M-D-Mercy Hosp. Gilbert Colina, Director2000 E. 5th St.

Durham“ Poison Control Center 684-8111 Jay Arena, M.D.Duke University Hosp. Shirley K. Osterhout,Box 3024 M.D.

HendersonvilleMargaret R. Pardee Oxford 3-6522 Fletcher L. Raiford, M.D.Memorial Hosp. Margaret Gretz, Pharm.Fleming St.

Jacksonville Poison Control Center 347-1241 S. C. Cox, M.D.Onslow Memorial Hosp. Eleanor Williams, M.D.College St.

Mount Airy Poison Control Center 786-4151 Ralph J. Sykes, M.D.Northern Hosp. of Ext. 211Surry County830 Rockford St.

Wilmington Poison Control Center 762‘8576 Joseph C- Knox, MD-New Hanover Me— M. E. Underwood

morial Hosp.2431 So. 17th St.

* 24 hour service and available for consultant work

Be sure toread labels for

inlarmatian an use

and safety precautionsfor all agricultural

chemicals

Published byTHE NORTH CAROLINA AGRICULTURAL EXTENSION SERVICE

North Carolina State University at Raleigh and the U. S. Department of Agricul-ture, Cooperating. State College Station, Raleigh, N. C. George Hyatt, Jr.,garecltor. Distributed in furtherance of the Acts of Congress of May 8 and June

, 9l4.February 1968 Leaflet No. 124