Weed ControlWeed ControlForFor

Certified Organic FarmersCertified Organic FarmersTom LaniniTom Lanini

University of California, Davis

Organic Weed ControlOrganic Weed Control• Mulches• Mulches• Water managementg• Cultivation• Flamers• Organic Herbicides• Organic Herbicides

MulchesMulches

• Act by blocking light• Numerous organic and

th ti t i l b dsynthetic materials can be used for this purposefor this purpose

Seedling Emergence relative to Light

Dark Light Light + Glass

600

Dark Light Light + Glass

No.

/m2 )

400

500

genc

e (N

200

300

ng e

mer

g

0

100

200

Seed

lin

0

String trimmer damage??Rodents???

LumiteM l hMulch

Wood chippMulch

Water ManagementWater Management

Preirrigation for weed seed d i i l ireduction prior to crop planting

Questions:Questions:• Is furrow irrigation any different than

sprinkler irrigation as a preirrigationsprinkler irrigation as a preirrigation methodH l h ld it ft• How long should you wait after preirrigation before weed removal

• What is the most effective method of weed removal – flamer or cultivation

Hand Weeding Time as Affected by Preirrigation and Weedby Preirrigation and Weed Removal Timing and Methodg

12

7 Day wait 14 Day wait

ot)

8

10

e (m

in/p

lo

6

8

edin

g tim

e

2

4

Han

d w

ee

0No Preirrigation Furrow Sprinkler

H

Preirrigation ConclusionsPreirrigation Conclusions• Maximum weed emergence occurred atMaximum weed emergence occurred at

120 to 130 cumulative degree days (base temperature = 10°C)temperature 10 C)

• Preirrigation/weed removal was less beneficial when weed density is lowbeneficial when weed density is low

• Hand weeding times are reduced if pre-i i ti d d l f dirrigation and weed removal are performed prior to crop planting.

CultivationCultivation• Best when weeds are small• Best when weeds are small• Dry conditions after cultivationDry conditions after cultivation

help to prevent re-rooting• Shallow cultivation reduces the

quantity of new seeds broughtquantity of new seeds brought to the surface

Weed Seed Emergence relative to Depth (inches)

Optimum depth Maximum depth

Wild oat 1 0 7 0Wild oat 1.0 7.0

Shepherdspurse 0.2 0.8

Lambsquarters 0.3 2.0

Crabgrass 0.4 1.6gFoxtail 1.0 3.0

Chi k d 0 4 0 8Chickweed 0.4 0.8King 1966

Night Cultivation?Night Cultivation?• Some studies have found that• Some studies have found that

cultivation at night reduces weed germination

• GPS guided systems (?)• GPS guided systems (?) • Better results after repeat treatmentsp• At worst, you lose a little sleep

Propane FlamersPropane FlamersKills eeds like a contact• Kills weeds like a contact herbicideherbicide

• Treated leaves go from a glossy g g yto a mat finish

• Fuel cost??

Just prior to flaming

5 minutes after flaming

10 minutesafter flaming

Organic HerbicidesOrganic Herbicides Registered for Not Registered forRegistered for

Food UseNot Registered for Food Use

• C-Cide• Green Match O • Pine Oil

• Matran EC• Weed Zap

• Racer*• Acetic Acid –• Weed Zap

• Green Match EXmust be food grade

All are contact type herbicides – no residual activity

C-Cide 33% @ 70 GPA55º F at application

C-Cide 33% + 1% NuFilm P@ 70GPA 74ºF

C-Cide 33% + 1% NuFilm P @ 70GPA10 DAT

C-Cide 25% 70gpa + 0.5% Natural Wet81 ºF at application

C-Cide 25% 70gpa + 0.5% Natural WetC Cide 25% 70gpa 0.5% Natural Wet81 ºF at 1st and 76 ºF at 2nd application – treated twice

For Control of Annual and BroadleafWeeds In Non-Crop AreasACTIVE INGREDIENT: d-limonene …………… 70%INERT INGREDIENTS 30%INERT INGREDIENTS:……….…..………….…. 30%Total ........................................................................100%KEEP OUT OF REACH OF CHILDRENCAUTIONEPA R N 82052 1EPA Reg. No. 82052 - 1EPA Est. No. 82052-GA-1Manufactured by:Cutting Edge Formulations, Inc.5106 Bristol Industrial WayyBuford, GA 30518(866) 906-WEEDDIRECTIONS FOR USE:It is a violation of Federal Law to use this product in a manner inconsistent with its labeling.General information: GREENMATCH O is a broad spectrum weed killer that contains aGeneral information: GREENMATCH O is a broad spectrum weed killer that contains acitrus extract. It is non-selective and controls most annual weeds, both grasses and broadleaves.For best performance, complete coverage of target weeds is necessary. Spray until thoroughlywet. It is recommended for non-food areas such as borders, driveways, sidewalks, around maturetrees and ornamentals, around buildings, in greenhouses and around flower beds.

GreenMatch O 10% + 1% NuFilm P @ 70 GPA55ºF at application

GreenMatch O 15% + 1% Natural wet@ 70gpa 81º F

GreenMatch O 15%+ 1% Natural wetGreenMatch O 15%+ 1% Natural wet @ 70gpa - treated twice

Matran EC 10% + 1% Natural Wet @ 35 GPA55º F at application

Matran EC 15% + 1% Natural Wet @ 35 GPAMatran EC 15% + 1% Natural Wet @ 35 GPA55º F at application

Matran EC 10% + 1% NuFilm P @ 70 GPA 74º F

Matran EC 10% + 1% NuFilm P @ 70 GPA 10 DAT@ 70 GPA 10 DAT

Matran 15% + 0.05% Natural wet @ 70 gpa

Vinegar 20% + 1% NuFilm P @ 70 GPA 55ºF@ 70 GPA 55 F

Vinegar 20% + 1% NuFilm P @ 70 GPA Treated twice

Vinegar 20% + 1% NuFilm P @ 70 GPA 74ºF

Vinegar 20% + 1% NuFilm PVinegar 20% + 1% NuFilm P @ 70 GPA 10 DAT

Vinegar 20% 70gpa + 0 05% Natural WetVinegar 20% 70gpa + 0.05% Natural Wet81ºF at application

Vinegar 20% 70gpa + 0.05% Natural Wet –Treated twice

0.25% v/v Natural Wet35 gallons per acre spray volume

16 Days after treatment

WeedZap 15% + 1% Natural Wet @ 35 GPA55º F at applicationpp

WeedZap 20% + 1% NuFilmP @ 35 GPA 10 DAT

WeedZap 10% @ 70 GPAp @10 DAT

WeedZap 10% 70gpa + 0 05% Natural wet+ 0.05% Natural wet

GreenMatch EX 15% @ 35 GPA10 days after application10 days after application

GreenMatch EX 15% 70gpa +gp0.05% Natural wet

GreenMatch EX10% 70 GPA10% 70 GPA1% NuFilm P

Does age (size) make a difference?2 d li i d2nd application date

Youngest Oldest

8090

100

g

%)

50607080

ntro

l (%

20304050

rass

co

01020

C-Cide GreenM GreenM EX Matran Vinegar WeedZap

Gr

S. Horimoto, unpublished

Organic Adjuvants

Organic adjuvantsOrganic adjuvants

Matran 10% - 2 DAT

Matran 10% + Organic Adjuvant 1% - 2 DAT

M t + WE 1098 1 DATMatran + WE 1098 – 1 DAT

Matran + WE 1098Matran + WE 1098 8 DAT

Organic HerbicidesOrganic Herbicides• Good spray coverage is essential

70 GPA?• Work better in warm (sunny?) weather (80ºF)• Organic adjuvants improve weed control• Organic adjuvants improve weed control• Treat when weeds are small• Repeat applications are needed for larger

weeds

PreventionPrevention• Avoid letting weeds go to

seedseed

• Do not let weeds come in on equipment

Questions?