Plant Biotechnology: Current and Potential Impact

For Improving Pest Management In U.S. Agriculture

An Analysis of 40 Case Studies June 2002

Herbicide Tolerant Soybean

Leonard P. Gianessi Cressida S. Silvers

Sujatha Sankula Janet E. Carpenter

National Center for Food and Agricultural Policy

1616 P Street, NW Washington, DC 20036 Phone: (202) 328-5048 Fax: (202) 328-5133

E-mail: ncfap@ncfap.org Website: www.ncfap.org

Financial Support for this study was provided by the Rockefeller Foundation, Monsanto, The Biotechnology Industry Organization, The Council for Biotechnology Information, The Grocery Manufacturers of America and CropLife America.

2

26. Soybean

Herbicide Tolerant

Production

Thirty-one states have significant soybean acreage (Table 26.1). Soybean production is

centered in the Midwest where ten states account for 73% of U.S. acreage and

production. The states of Illinois and Iowa each account for more than 10 million acres of

soybeans

The total value of the soybean crop was $13 billion in 2000, representing approximately

15% of the value of all crops grown in the U.S. Table 26.1 shows production values by

state. Figure 26.1 charts average US soybean yields 1995-2001.

Weed Competition

Weeds compete with soybeans for soil moisture, nutrients, sunlight and space in the field.

One cocklebur may occupy four to eight square feet of area, thereby reducing the space

available for soybean growth. When weeds shade the soybean plant, less sunlight is

available for soybean production. Most of the soybean yield reduction from velvetleaf

and pigweeds is ascribed to shading by the weed leaves above the soybean canopy. As a

result of competing with soybeans, uncontrolled weeds decrease the quantity of soybean

seeds produced [44].

The efficiency of operation of harvesting equipment is also reduced by the presence of

significant numbers of weeds [45]. The quality of the harvested crop is directly impacted

by weeds. Increases in moisture content, foreign matter, and splits have been

documented when high levels of weeds are present at harvest [45].

Numerous reports in the literature quantify the effects of full- or partial-season weed

interference on soybean seed yields. The data show considerable differences among

species in interfering ability. Common cocklebur is the most interfering weed: 1 plant/m2

depresses soybean yield by 30% while nine plants/m2 depresses soybean yield by 80%. A

3

less competitive weed species for soybeans is giant foxtail: 16 plants/m2 depresses

soybean yield by only 10%.

More than thirty plant species infest soybean fields in the major soybean producing areas

of the U.S. [46]. Annual broadleaf and grass weeds are major problems. In some areas,

perennial grass, broadleaf weeds and sedges are troublesome. Table 26.2 lists the 22 most

common weed species in soybean fields in 29 of the major soybean producing states.

Ragweed, foxtail, nightshade, lambsquarters, smartweed, and velvetleaf infest more

acreage in the Midwest than in the Delta. Morningglory, barnyardgrass, signalgrass,

prickly sida, hemp sesbania and sicklepod infest more acreage in the Delta. Cocklebur,

johnsongrass, crabgrass and pigweeds are estimated to infest sizable acreages of soybeans

in all soybean producing regions.

Natural weed populations in most fields are high enough to cause devastating soybean

yield losses if left uncontrolled [47]. Loss figures of 50 – 90% are common for soybeans

grown in natural weed infestations [48] [49] [50] [51].

Research has shown that a period of 4 to 6 weeks without weed competition at the

beginning of the growing season will allow production of maximum yields under most

environmental conditions [47]. Any weed emerging in the crop after this initial weed

free period will not compete effectively with soybeans and will not affect yield potential

due to the soybean canopy which shades emerging weeds. Similarly, a period of 4 to 6

weeks of weed interference at the beginning of the season usually can be tolerated by

soybeans with no significant yield loss provided that the crop is maintained weed free for

the remainder of the season [47].

Herbicide Use

By the early 1990’s, there were at least 70 registrations for individual herbicides or

packaged herbicide mixtures for weed management in soybeans.

Table 26.3 tracks herbicide use in soybeans 1995-2001.

4

The most widely-used soybean herbicides in 1995 were from the sulfonylurea and

imidazolinone chemical classes (imazethapyr, imazaquin, chlorimuron, thifensulfuron).

These active ingredients controlled a large number of broadleaf species and when

combined with pendimethalin or trifluralin provided effective control of most grass and

broadleaf species common in soybean fields in the Midwest [81]. The sulfonylureas and

imidazolinones are similar in their mode of action. They are absorbed readily by roots

and foliage of plants. Herbicide activity by the sulfonylureas and imidazolinones results

from inhibition of the enzyme acetohydroxyacid (AHAS, acetolactate synthase, ALS),

which stops the synthesis of three essential amino acids – valine, leucine and isoleucine

[82].

The widespread use of ALS herbicides quickly led to the development of resistant weed

populations. Weeds that evolved resistance to ALS inhibitors evolved altered ALS that is

resistant to the herbicide. Resistance to ALS-inhibiting herbicides has been confirmed in

kochia, Russian thistle, common waterhemp, Palmer amaranth, common cocklebur,

shattercane, giant ragweed and common sunflower [83] [84].

In Missouri and Kansas, common waterhemp resistant to the sulfonylureas and

imidazolinones become the principal weed problem in soybeans with over 900,000 acres

of soybeans infested [43].

The prevalence of herbicide resistant weeds led to postemergence mixtures of active

ingredients for broad range weed control.

During the 1990’s soybean growers increasingly shifted towards postemergence

herbicide use. By 1995, only 23% of the nation’s soybean acreage

received only a before or at-plant soil applied herbicide – representing a 50% reduction in

such treatments between 1990 and 1995. The average number of treatments per acre rose

from 1.5 in 1990 to 1.7 in 1995 as it was more common for soybean growers to

make both an at-plant and postemergence treatment or make two postemergence

5

treatments [59].

A steady increase in the number of herbicide active ingredients applied to treated soybean

acreage occurred between 1986 and 1995: from 1.4 to 2.7. [60] [61] [62]

In 1995, 23% of the nation’s soybean acreage was treated with a combination of four or

more active ingredients while 28% received three active ingredients, 35% received two

active ingredients and 12% was treated with just a single herbicide active ingredient [60].

In 1994, 43% of U.S. soybean acreage were cultivated during the growing season [52].

The average cultivated acre was cultivated one time during the season in 1994.

Cultivations were targeted at weeds that escaped standard herbicide treatments.

Transgenic Soybeans

After being absorbed by plants, the herbicide glyphosate inhibits the enzyme 5-

enolpyruvylshikimate-3-phosphate synthase (EPSPS). Glyphosate binds to EPSPS

resulting in EPSPS’s inhibition, causing the plant to starve for EPSP and the metabolic

products derived from EPSP [53].

The ability to metabolize glyphosate is distributed widely among soil bacteria. Research

demonstrated that EPSPS from a number of bacteria exhibited tolerance to

glyphosate [53]. Monsanto scientists collected bacterial cultures from diverse sources

and analyzed them for their tolerance to glyphosate. The EPSPS with the highest

tolerance to glyphosate found in the screening was CP4 EPSPS from agrobacterium

tumifacien, that demonstrated extremely high glyphosate tolerance [53].

The gene from CP4 EPSPS was cloned and introduced into soybeans by the particle

acceleration method. Soybean cultivar A5403, a commercial variety developed by

ASGROW Seed Company was used for the transformation [54].

The lead soybean line with a Roundup Ready gene is denoted 40-3-2, and expresses the

6

CP4 EPSPS gene product. Upon glyphosate treatment the transgenic plant remains

unaffected because the continued action of the introduced glyphosate-tolerant EPSPS

enzyme meets the plant’s need for aromatic amino acids. The endogenous EPSP is

inhibited by glyphosate (upon glyphosate treatment), however, the plant relies on the

introduced glyphosate-tolerant EPSPS for EPSP synthesis [53].

Line 40-3-2 has been used in various breeding programs to develop new cultivars with a

Roundup Ready gene (Roundup Ready is Monsanto’s trademark for its genes conferring

glyphosate tolerance). Over 150 seed companies offer more than 1,000 Roundup-Ready

varieties.

The use of glyphosate over-the-top of Roundup Ready soybeans was researched

extensively prior to and immediately after their introduction in 1996. Roundup Ready

soybeans were evaluated under an EUP in 1995 in 14 states in the Midwest and Mid

Atlantic. A single application of glyphosate at 0.63-0.84 kg/ha provided annual weed

control throughout the entire growing season [55].

In a 1997 experiment, all application timings of glyphosate (at weed heights of 7.5, 15,

23 and 36 cm) provided season-long control of giant foxtail, common lambsquarters and

common cocklebur. The 7.5 cm timing was the only treatment to provide better than

90% control of smartweed. (All other glyphosate treatments provided 78-89% control.)

All glyphosate applications provided yields equal to the weed-free comparison. All

comparison treatments yielded significantly lower than weed-free comparison [56].

Research has shown in northern soybean states that a single postemergence application of

Roundup controls all weeds commonly found in soybeans. [64]

Figure 26.2 shows the increase in planting of Roundup Ready soybeans in the US since

their introduction in 1996. The Roundup Ready technology was planted on two-thirds of

the nations soybean acres in 2001. Table 26.4 shows adoption of Roundup Ready

soybeans by state in 2001.

7

Table 26.3 shows estimates of U.S. soybean acreage treated with individual active

ingredients for the years 1995-2001. Glyphosate usage increased to 76% of acreage

treated in 2001, from 20% in 1995 (used as a burndown or spot treatment), while most

other active ingredients recorded declines in acreage treated. Postemergence glyphosate

applications largely replaced the previous widespread use of the ALS-inhibiting

herbicides (imazethapyr, imazaquin) and the herbicides that had been used in

combination with them (pendimethalin, trifluralin). Recent research indicates that

glyphosate alone provides superior weed control and soybean yields in comparison to

these previously-used standard treatments (see Table 26.5).

In addition to changing herbicide use patterns, US soybean growers have also changed

tillage practices following the introduction of Roundup Ready soybeans. A recent survey

by the American Soybean Association indicated that 53% of US soybean growers

reported making fewer tillage passes through their fields since 1995 with the average

reduction reported as 1.8 tillages/acre [63]. Improved weed control in the Roundup

Ready system reduced the need to cultivate.

Table 26.6 shows estimates of the costs and herbicide amounts used with the Roundup

Ready soybean system by state. The average use rate of glyphosate is estimated at .95 lb

AI/A. The system costs US soybean growers $475 million in herbicide costs and $300

million in technology fees. The total cost of the Roundup Ready technology is

approximately $15.51 per acre.

Alternative Herbicides

Several new herbicide active ingredients and combination products were introduced to

the US soybean market 1997-2001 including Boundary, Authority, Flexstar, Raptor,

Harmony GT and FirstRate [67], [68], [69]. Several of these products contain active

ingredients that are ALS inhibitors (FirstRate, Harmony GT, Raptor) and as a result,

cannot effectively control ALS-resistant weed populations. Generally these active

ingredients have been shown to work best in combination with other products which

8

extend the period or spectrum of control. For example FirstRate needs to be combined

with other products such as Dual or Python for effective control of lambsquarters and

pigweed [69]. Boundary is being marketed as a preemergence component with a

preplanned postemergence application [67]. Authority contains an active ingredient,

sulfentrazone, that is particularly effective in controlling weed species that have

developed populations resistant to ALS inhibitor herbicides. As a result, one of its

primary uses is in a combination product , Canopy XL, with chlorimuron.[70]

Experiments in Illinois demonstrated that a combination of Flexstar and Fusion provided

96-99% control of foxtail, pigweed, ragweed, and smartweed [66]. However, this

combination only provides fair control of cocklebur, lambsquarters, and velvetleaf.

University extension weed control guides rate as many as 190 herbicide treatments for

soybeans that do not contain glyphosate [35].

One of the reasons that the Roundup Ready technology expanded so rapidly is due to the

effectiveness of glyphosate on a broad spectrum of weed species. Table 26.7 displays

effectiveness ratings for Roundup and 20 major product alternatives. 12 of the product

alternatives contain a single active ingredient while 8 are combinations of two active

ingredients. Table 26.8 lists the 20 alternatives with their active ingredient names, rates of

application and costs. Roundup’s effectiveness is rated at least ‘good’ on 20 of the 22

weed species infesting soybeans (Table 26.7). For the other two species Roundup

provides ‘fair’ control. The highest number of good and excellent ratings for an

alternative is 17 for Boundary, which is a combination of metribuzin and s-metolachlor.

All other alternatives score between 4 and 13 good or excellent ratings. Although rated

good-excellent on a large number of weeds, Boundary is applied preemergence and does

not provide season-long control. As a result weed guides indicate that Boundary must be

followed with a planned postemergence herbicide program (see above) [36], [40].

One of the reasons for rapid adoption of Roundup Ready soybeans is the excellent control

it provides of common waterhemp which (as noted above) had grown resistant to many of

9

the conventional herbicides [65]. In 1996 experiments, imazaquin, imazethapyr and

chlorimuron provided 15-25% control of common waterhemp while .75 lb. AI of

glyphosate applied over glyphosate tolerant soybeans provided 98% control [57] [58].

Recent tests with newly-registered active ingredients indicate that combinations of 4-5

active ingredients could provide effective weed control of common grasses and

broadleaves approximately equal to those provided by Roundup. Tables 26.9 and 26.10

display recent research results for combinations of herbicide active ingredients in

comparison to the use of glyphosate.

Estimated impacts

A survey of Extension Service weed scientists solicited herbicide replacement scenarios

for Roundup. Responses were received from 23 of the major soybean producing states.

These herbicide replacement scenarios are presented in Table 26.11. Replacement

scenarios have been assigned to the other 8 states based on a neighboring state. For most

states, the specialists indicated that at least 3 products would have to be used to

effectively replace Roundup. These combinations would be required in order to achieve

good or excellent control (Table 26.7) of the most common weed species in the state

(Table 26.2). Table 26.12 displays estimates of the per-acre costs and use rates for the

Roundup and alternative program by state. Most Roundup programs use approximately 1

lb AI and cost $15-16/A. Most alternative programs cost $30-40/A and utilize more than

one pound of active ingredient per acre.

Table 26.13 simulates the replacement of the Roundup program with the alternative

program by state. The estimates are presented in terms of the impacts of the Roundup

program having been adopted instead of the alternative programs. US soybean growers

are saving approximately $1.0 billion per year from using the Roundup program instead

of the alternative programs. The Roundup program results in a reduction of 28.7 million

pounds of herbicide active ingredients applied to soybeans.

10

The estimate of $1.0 billion in cost savings due to Roundup Ready soybeans is

considerably higher than previous NCFAP estimates of $216-220 million/year [76]. The

earlier estimates measured reductions in herbicide expenditures by all soybean growers as

a result of reduced prices for herbicides, which resulted from the introduction of the

Roundup Ready technology. The aggregate total of $220 million/year implies a savings

of $2.93/a on 75 million soybean acres in 2000. No estimates were made in the earlier

reports of the reduced cost of tillage or of reduced cost of making fewer herbicide

application trips across the field. USDA survey data for 2001 indicate that US soybean

growers applied glyphosate an average of 1.3 times per acre [2]. As noted above, the

average soybean acre was treated 1.7 times with herbicides in 1995. Assuming a

reduction of .4 trips per acre at a cost per trip of $3/A [77] implies an aggregate reduction

of herbicide application costs of $60 million/yr on 50 million acres planted with Roundup

Ready soybeans. A reduction of 1.8 tillage trips has been recorded on approximately one-

half of US soybean acreage since the planting of Roundup Ready soybeans began (see

above) assuming $6/A for a cultivation trip [78] implies an aggregate reduction in

cultivation costs of $315 million.

The impact estimates in this report represent a simulation of the costs that growers would

incur if they replaced the Roundup Ready program with an equally effective herbicide

program to control problem weeds without the need for additional cultivation. Most of

the replacement scenarios specified by University weed scientists rely on newly-

registered herbicide active ingredients and combination products. It is not likely that

soybean growers would simply return to the herbicide programs that they were using

before the introduction of the Roundup Ready program. As noted above, significantly

large resistant weed populations had developed for the most widely-used herbicides-

imazethapyr and other ALS inhibitors. In addition, the previously-used herbicides did not

control all the important weed species season-long and had to be supplemented with

cultivation.

Soybean farmers have become used to the benefits of the Roundup Ready system – the

use of one herbicide active ingredient to control all of the important weed species in one

11

or two applications without the need for supplemental cultivation. The scenarios specified

in this analysis of alternative herbicides for glyphosate accomplish the same end result-

control of the important weed species in one or two applications without the need for

supplemental cultivation ---but at a higher cost ($20/A on 50 million acres).

No estimates are made of the impact on soybean production of the adoption of the

Roundup Ready technology. Several states (NY, KS, SD) have recorded substantial

increases in soybean acreage since the introduction of Roundup Ready soybeans (see

Figure 26.3). One of the major reasons for the expanded acreage in these states is the

widespread planting of Roundup Ready soybeans which provides growers in these states

with an economical means of controlling particularly tough weed species [79].

An emerging concern with Roundup Ready soybean technology is the development of

glyphosate resistant weed populations – such as Marestail, which has been confirmed to

be resistant in several states and may require additional management tactics.

12

Table 26.1 Soybean Acreage, Production and Value: 2000

State

Area Harvested

(000A)

Yield (Bushels)

Production (000Bushels)

Price per Bushel

($)

Value of Production (Million $)

AL 160 18 2880 4.75 13AR 3200 26 83200 4.90 407DE 213 43 9159 4.60 42FL 15 19 285 4.45 1GA 160 24 3840 4.50 17IL 10450 44 459800 4.85 2230IN 5630 46 258980 4.75 1230IA 10680 43 459240 4.75 2181KS 2500 20 50000 4.75 237KY 1180 39 46020 4.85 223LA 870 26 22620 5.05 114MD 515 43 22145 4.60 101MI 2080 36 74880 4.75 355MN 7150 41 293150 4.60 1348MS 1580 22 34760 5.00 173MO 5000 35 175000 4.75 831NE 4575 38 173850 4.70 817NJ 98 40 3920 4.40 17NY 132 33 4356 4.55 19NC 1360 33 44880 4.65 208ND 1850 33 61050 4.20 256OH 4440 42 186480 4.80 895OK 310 15 4650 4.30 19PA 395 43 16985 4.40 74SC 440 25 11000 4.50 49SD 4370 35 152950 4.45 680TN 1150 25 28750 4.80 138TX 260 27 7020 4.35 30VA 490 39 19110 4.20 80WV 15 47 705 4.60 3WI 1450 40 58000 4.70 272 Total 72718 38 2769665 4.75 13073Source: [41] [42]

13

Table 26.2: Most Common Weed Species: Soybeans AL AR DE FL GA IL IN IA KS KY LA MD MI MN MS Cocklebur X X X X X X X X X X X X X X

Morningglory X X X X X X X X X X X X Pigweed X X X X X X X X X X X X X X Sicklepod X X X X X X Lambsquarters X X X X X X X X Ragweed X X X X X X X X FL Beggarweed X X Fl Pusley X X Velvetleaf X X X X X X X X Smartweed X X X X X Jimsonweed X X X X X Hemp sesbania X X X Prickly sida X X X X Crabgrass X X X X X X X X X X Foxtail X X X X X X X X X Panicum X X X X X X Goosegrass X X X Signalgrass X X X Barnyardgrass X X X Johnsongrass X X X X X X X X X Shattercane X X Nutsedge X X X X X X Source [3] [4]

14

Table 26.2: Most Common Weed Species: Soybeans (cont.)

MO NE NJ NC ND OH OK PA SC SD TN TX VA WI Cocklebur X X X X X X X X X X X X Morningglory X X X X X X X X X X Pigweed X X X X X X X X X X X X X Sicklepod X X X Lambsquarters X X X X X X X X X X X X Ragweed X X X X X X X X FL Beggarweed X Fl Pusley Velvetleaf X X X X X X X X Smartweed X X X Jimsonweed X X Hemp sesbania X X Prickly sida X X X Crabgrass X X X X X X X Foxtail X X X X X X X X Panicum X X X X X X Goosegrass X X X Signalgrass X X X Barnyardgrass X Johnsongrass X X X X X X X X Shattercane X X X Nutsedge X X X Source: [3] [4]

15

Table 26.3 Herbicide Use, US Soybeans (% Acres Treated) 1995 1996 1997 1998 1999 2000 20012,4-D 10 13 8 7 5 5 42,4-DB 1 <1 1 <1 <1 Acifluorfen 12 11 12 7 3 3 3Alachlor 4 5 3 2 2 1 <1Bentazon 12 11 11 7 4 2 1Chlorimuron 16 14 13 12 12 10 5Clethodim 5 7 4 4 5 4 4Clomazone 4 3 5 4 1 <1 <1Cloransulam 1 5 4 5Dimethenamid 1 1 1 1 <1 <1 Ethalfluralin 1 1 <1 <1 <1 Fenoxaprop 6 4 6 4 4 4 3Fluazifop 10 7 7 5 4 5 3Flumetsulam 2 2 4 2 2 2 <1Flumiclorac 2 1 <1 <1 <1 <1Fomesafen 4 5 6 6 4 7 7Glyphosate 20 25 29 47 62 66 76Imazamox 7 3 6 5Imazaquin 15 15 13 8 5 4 2Imazethapyr 44 43 38 17 16 12 9Lactofen 5 8 4 2 2 2 1Linuron 2 1 1 <1 <1 <1 Metolachlor 7 5 7 4 4 2 Metribuzin 11 9 10 6 5 4 2Paraquat 2 1 2 1 1 <1 Pendimethalin 26 27 25 18 14 11 10Quizalofop 6 7 4 3 1 <1 <1S-Metolachlor <1Sethoxydim 7 9 7 5 3 2 1Sulfentrazone 3 4 4 5Thifensulfuron 12 10 9 5 5 6 2Trifluralin 20 22 21 16 14 14 7Source: [2]

16

Table 26.4 Herbicide Tolerant Transgenic Soybean Adoption: 2001 State Area Harvested

(000A) %

HT HT Acres

(000A)

Source

AL 160 70 112 [5] AR 3200 60 1920 [1] DE 213 80 170 [6] FL 15 80 12 [7] GA 160 80 128 [8] IL 10450 64 6688 [1] IN 5630 78 4391 [1] IA 10680 73 7796 [1] KS 2500 80 2000 [1] KY 1180 40 472 [2] LA 870 76 661 [2] MD 515 65 335 [9] MI 2080 59 1227 [1] MN 7150 63 4504 [1] MS 1580 63 995 [1] MO 5000 69 3450 [1] NE 4575 76 3477 [1] NJ 98 70 69 [10] NY 132 85 112 [11] NC 1360 74 1006 [2] ND 1850 49 906 [1] OH 4440 64 2842 [1] OK 310 60 186 [12] PA 395 80 316 [13] SC 440 80 352 [14] SD 4370 80 3496 [1] TN 1150 85 978 [2] TX 260 65 169 [15] VA 490 65 318 [16] WV 15 90 14 [17] WI 1450 63 914 [1] Total 72718 69 50016

17

Table 26.5 Iowa Herbicide Performance Evaluation: Soybeans (1) Imazethapyr

+ Pendimethalin

Glyphosate

Weed Control (%) Foxtail 95 99 Velvetleaf 57 99 Waterhemp 80 95 Lambsquarters 99 99

Yield (bu/A) 35 39 Source: [72]

18

Table 26.6 Herbicide Use and Cost, Transgenic Soybean Acreage State

HT

Acreage (000)

Lbs. AI

Technology Fee (000$)1

Herbicide

Cost2 (000$)

Total Cost

Source3

Per Acre (000/yr.) (000$) ($/A)

AL 112 1.00 112 672 1120 1792 16.00 [5]AR 1920 0.94 1805 11520 18050 29570 15.40 [2]DE 170 1.00 170 1020 1700 2720 16.00 [6]FL 12 1.00 12 72 120 192 16.00 [7]GA 128 1.00 128 768 1280 2048 16.00 [8]IL 6688 0.91 6086 40128 60860 100988 15.10 [2]IN 4391 0.97 4259 26346 42590 68936 15.70 [2]IA 7796 0.93 7250 46776 72500 119276 15.30 [2]KS 2000 0.87 1740 12000 17400 29400 14.70 [2]KY 472 0.80 378 2832 3780 6612 14.01 [2]LA 661 1.11 734 3966 7340 11306 17.10 [2]MD 335 1.00 335 2010 3350 5360 16.00 [9]MI 1227 0.98 1202 7362 12020 19382 15.80 [2]MN 4504 0.94 4234 27024 42340 69364 15.40 [2]MS 995 1.22 1214 5970 12140 18110 18.20 [2]MO 3450 0.97 3346 20700 33460 54160 15.70 [2]NE 3477 0.91 3164 20862 31640 52502 15.10 [2]NJ 69 1.00 69 414 690 1104 16.00 [10]NY 112 1.00 112 672 1120 1792 16.00 [11]NC 1006 0.79 795 6036 7950 13986 13.90 [2]ND 906 0.99 897 5436 8970 14406 15.90 [2]OH 2842 0.92 2615 17052 26150 43202 15.20 [2]OK 186 1.50 279 1116 2790 3906 21.00 [12]PA 316 1.00 316 1896 3160 5056 16.00 [13]SC 352 1.00 352 2112 3520 5632 16.00 [14]SD 3496 1.02 3566 20976 35660 56636 16.20 [2]TN 978 1.04 1017 5868 10170 16038 16.40 [2]TX 169 1.50 254 1014 2540 3554 21.02 [15]VA 318 1.00 318 1908 3180 5088 16.00 [16]WV 14 1.00 14 84 140 224 16.00 [17]WI 914 0.87 795 5484 7950 13434 14.70 [2] Total 50,016 0.95 47,568 300,096 475,680 775,776 $15.51

1Calculated at $6/A [75] 2Calculated at $10/Lb AI [36] 3Source of per acre rate

19

Table 26.7 Effectiveness Ratings: Soybean Herbicides Weed species R

ound

up

Pyth

on

Cla

ssic

Ref

lex

Dua

l II

Mag

num

Can

opy

XL

Bou

ndar

y

Flex

star

Fusi

on

Can

opy

Purs

uit

Aut

hori

ty

Firs

trat

e

Stor

m

Squa

dron

Sele

ct

Rap

tor

Har

mon

y G

T

Purs

uit P

lus

Ass

ure

Sync

hron

y

Cocklebur E F-G E F N F-G G F N F-G E P E G F-G N E F F N E

Morningglory F-G P P-F F-G N F-G F-G F-G N F F-G E G F-G P N F-G P F N F Pigweed E E E E G E E E N E E G P F E N E E E N E Sicklepod F-G F-G F-G P-F N F G P-F N F-G P P P F-G N P P N F-G Lambsquarters F-G G-E P P P-F G E F N G-E P G N P F-G N F E G N E Ragweed F-G P F E P G G E N G P-F F G-E F-G P-F N F N-P F-E N F FL Beggarweed G F G G F G G P N G-E P P-F F-G P P N N E FL Pusley P-F E G G G N G-E F P-F F E E N N F Velvetleaf F-G G P-F P N F G P-F N F F-G F P-F F-G P-F N F-G G G N G Smartweed F-G E F-G F P E E F N G-E F-G P G F-G F-G N F-G G G N G Jimsonweed E F-G E G N F-G F E N F-G G P E E F-G N G P F N E Hemp sesbania G N G E N F E E N E N P E N N N E Prickly sida F-G F-G P P P F-G G N N G-E P G P F F-G N F P G N P Crabgrass E N P N E P E N G F F-G N N F E F-G N G-E F-G N Foxtail E N P N E P-F E N E F F-G F N N G E G N E G N Panicum G-E N P N G-E P E N E F F P-F N N F-G E F-G N G-E E N Goosegrass E N N N E P E N G P P P-F N N F G P N G N Signalgrass E N N N F-G P E N G P-F F-G P-F N N F-G G-E F-G N G N Barnyardgrass E N N N G-E P E N E F F F N N G-E E F-G N E G-

E N

Johnsongrass G-E N P N N-P N-P P-F N G-E N-P P-G P N N N-F G-E P-G N G-E

N

Shattercane G N P N P P P N E P G N N F E G N G E N Nutsedge P-F N P-F N F P F N N P P F N N P N P P F N N

Source: [31]-[39] E: Excellent G: Good F: Fair P: Poor N: None

20

Source: [31] [32] [37] [40]

Table 26.8 Rates and Costs of Alternative Herbicides for Soybeans Trade name

Common Name

Rate

(formulated product/A)

Rate (Lb AI/A)

Cost ($/A)

Classic Chlorimuron 0.67 oz 0.01 7.70 Reflex Fomesafen 1.5 pt 0.375 15.00 Dual II Magnum S-Metolachlor 1.5 pt 1.43 19.69 Canopy XL Sulfentrazone + Chlorimuron 6 oz 0.21 14.46 Boundary Metribuzin + s-Metolachlor 1.25 pt 1.22 11.74 Flexstar Fomesafen 1 pt 0.24 11.25 Fusion Fluazifop + Fenoxaprop 10 oz 0.21 10.30 Canopy Chlorimuron + Metribuzin 4 oz 0.19 8.60 Pursuit Imazethapyr 1.44oz 0.063 15.00 Authority Sulfentrazone 4 oz 0.19 10.60 FirstRate Cloransulam 0.3 oz 0.016 7.20 Storm Acifluorfen + Bentazon 1.5 pt 0.75 14.05 Squadron Imazaquin + Pendimethalin 3 pt 0.88 14.76 Select Clethodim 8 oz 0.125 11.55 Raptor Imazamox 5 oz 0.039 18.55 Harmony GT Thifensulfuron 0.5 oz 0.024 5.50 Pursuit Plus Imazethapyr + Pendimethalin 2.5 pt 0.94 13.45 Assure II Quizalofop 8 oz 0.1 8.15 Synchrony Chlorimuron + Thifensulfuron 0.5 oz 0.013 2.06 Python Flumetsulam 1.0 oz 0.053 9.00

21

Table 26.9 Minnesota Herbicide Performance Evaluations in Soybeans Treatments

Flumetsulam +

Cloransulam +

Clethodim +

Lactofen

Sulfentrazone

+ Cloransulam

+ Fluazifop

+ Fenoxaprop

S-Metolachlor

+ Metribuzin

+ Fomesafen

+ Fenoxaprop

+ Fluazifop

Fomesafen

+ Fluazifop

+ Fenoxaprop

+ Thifensulfuron

Glyphosate

Weed Control (%) Foxtails 93 96 99 88 100 Lambsquarters 100 100 100 91 99 Pigweed 100 100 100 97 100 Wild Mustard 100 100 100 100 99

Yield (bu/A) 47 47 50 47 51-53 Source: [71] Table 26.10 Iowa Herbicide Performance Evaluation: Soybeans (2) Cloransulam

+ Fomesafen

+ Clethodim

Cloransulam +

Lactofen +

Clethodim

Glyphosate

Weed Control (%) Foxtail 92 88 99 Velvetleaf 99 99 96 Waterhemp 72 96 85 Ragweed 99 99 95 Lambsquarters 62 37 99 Venice Mallow 99 99 95 Cocklebur 99 99 99 Source: [72]

22

Table 26.11 Herbicide Alternatives for Roundup for Soybeans State

Source

AL Storm + Squadron + Select [30] AR Storm + Squadron + Select [30] DE Canopy + Dual II Magnum + Reflex [6] FL Canopy + Dual II Magnum [7] GA Canopy + Dual II Magnum [8] IL Boundary + Flexstar + Fusion [18] IN Dual II Magnum + Pursuit + Storm [19] IA Boundary + Flexstar + Select [73] KS Boundary + FirstRate + Select [20] KY Storm + Squadron + Select [21] LA Storm + Squadron + Select [30] MD Dual II Magnum + Canopy XL + Raptor [9] MI Canopy XL + Harmony GT + Pursuit Plus [22] MN Boundary + Fusion + Reflex [74] MS Storm + Squadron + Select [23] MO Flexstar + Fusion + Boundary [30] NE Pursuit Plus + Authority [24] NJ Dual II Magnum + Canopy XL [10] NY Dual II Magnum + FirstRate + Python [11] NC Classic + Dual II Magnum + Canopy [25] ND Authority + Select + Harmony GT [26] OH Dual II Magnum + Pursuit + Storm [30] OK Boundary + Select [30] PA Dual II Magnum + Canopy XL + Assure [13] SC Classic + FirstRate + Assure [14] SD Authority + FirstRate + Select [27] TN Squadron + Flexstar + Select [28] TX Boundary + Select [30] VA Reflex + Synchrony + FirstRate [16] WV Reflex + Synchrony + FirstRate [30] WI Authority + Raptor + Assure [29] - Survey respondents specified several alternative programs that would be equally effective. For the purpose of this analysis, a single program is selected above.

23

Table 26.12 Cost and Use Rates: Roundup Ready and Alternative Programs1 State Roundup Program Alternative Program $/A Lb AI/A

$/A Lb AI/A

AL 16.00 1.00 40.36 1.755 AR 15.40 0.94 40.36 1.755 DE 16.00 1.00 43.29 1.995 FL 16.00 1.00 28.29 1.620 GA 16.00 1.00 28.29 1.620 IL 15.10 0.91 33.29 1.670 IN 15.70 0.97 48.74 2.243 IA 15.30 0.93 34.55 1.585 KS 14.70 0.87 29.99 1.361 KY 14.01 0.80 40.36 1.755 LA 17.10 1.11 40.36 1.755 MD 16.00 1.00 52.70 1.679 MI 15.80 0.98 33.41 1.174 MN 15.40 0.94 37.04 1.805 MS 18.20 1.22 40.36 1.755 MO 15.70 0.97 33.29 1.670 NE 15.10 0.91 24.05 1.130 NJ 16.00 1.00 34.15 1.640 NY 16.00 1.00 35.89 1.499 NC 13.90 0.79 35.99 1.630 ND 15.90 0.99 27.65 0.339 OH 15.20 0.92 48.74 2.243 OK 21.00 1.50 23.29 1.345 PA 16.00 1.00 42.30 1.740 SC 16.00 1.00 23.05 0.126 SD 16.20 1.02 29.35 0.331 TN 16.40 1.04 37.56 1.245 TX 21.02 1.50 23.29 1.345 VA 16.00 1.00 24.26 0.404 WV 16.00 1.00 24.26 0.404 WI 14.70 0.87 37.30 0.329 1Roundup Ready costs and use rates from Table 26.6. Alternative program costs and rates based on specified product alternatives in Table 26.11 and product costs and rates in Table 26.8.

24

Table 26.13 Herbicide Tolerant Transgenic Soybean Impacts: 2001

Changes In State HT Acres Production Costs Herbicide Use (000)

($/A) (000$) (Lbs. AI/A) (Lbs.)

AL 112 -24.36 -2728 -0.755 -84560AR 1920 -24.96 -47923 -0.815 -1564800DE 170 -27.29 -4639 -0.995 -169150FL 12 -12.29 -147 -0.620 -7440GA 128 -12.29 -1573 -0.620 -79360IL 6688 -18.19 -121654 -0.760 -5082880IN 4391 -33.04 -145079 -1.273 -5589743IA 7796 -19.25 -150073 -0.655 -5106380KS 2000 -15.29 -30580 -0.491 -982000KY 472 -26.35 -12437 -0.955 -450760LA 661 -23.26 -15375 -0.645 -426345MD 335 -36.70 -12294 -0.679 -227465MI 1227 -17.61 -21607 -0.194 -238038MN 4504 -21.64 -97466 -0.865 -3895960MS 995 -22.16 -22049 -0.535 -532325MO 3450 -17.59 -60685 -0.700 -2415000NE 3477 -8.95 -31119 -0.220 -764940NJ 69 -18.15 -1252 -0.640 -44160NY 112 -19.89 -2228 -0.499 -55888NC 1006 -22.09 -22223 -0.840 -845080ND 906 -11.75 -10645 +0.651 +589806OH 2842 -33.54 -95321 -1.323 -3759966OK 186 -2.29 -426 +0.155 +28830PA 316 -26.30 -8311 -0.740 -233840SC 352 -7.05 -2482 +0.874 +307648SD 3496 -13.15 -45972 +0.689 +2408744TN 978 -21.16 -20694 -0.205 -200490TX 169 -2.27 -384 +0.155 +26195VA 318 -8.26 -2627 +0.596 +189528WV 14 -8.26 -116 +0.596 +8344WI 914 -22.60 -20656 +0.541 +494474 Total 50016 -20.21 -1010765 -0.574 -28703001

25

Figure 26.1 US: Soybean Yields

0

10

20

30

40

50

95 96 97 98 99 00 01

Source: [42]

Figure 26.2 US: Roundup Ready Soybean Adoption

01020304050607080

95 96 97 98 99 00 01 02

Source: [1] [80]

% Acres

bu/A

26

Figure 26.3 Soybean Acres

020406080

100120140160180

95 96 97 98 99 0 1

NYSDKS

Source: [42]

1997=100

27

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