Steve WellerPurdue University

Purdue University is an Equal Opportunity/Equal Access institution.

Weed Management ComponentsWeed Management Components Prevention Cultural (rows for cultivation, rotations, fertilizer

placement, seeding rate, stale seedbeds, competitive variety, mulches – give the crop the advantage byvariety, mulches give the crop the advantage by minimizing early season competition)

Mechanical (plow, rotary hoe, row cultivation, hoe, others)others)

Chemical (herbicides) Biological (mycoherbicides, traditional biocontrol) Site specific (precision agriculture, in field heterogeneity,

macro and micro scale) Integration of tactics Integration of tactics

Ti f S f l W d C t lTips for Successful Weed Control

1. Know what weed species you haveand choose control methods to match

2 C t l d h th ll2. Control weeds when they are small3. Minimize soil compaction4 Calibrate sprayer4. Calibrate sprayer5. Read and follow labels6 Maintain and adjust cultivation equipment6. Maintain and adjust cultivation equipment7. Educate, monitor, encourage weeding crew 8 Have a back-up plan8. Have a back-up plan9. Don’t let weeds go to seed

Crop HealthpRapid canopy cover will reduce weed growth

Plant when temperature is above 60Apply nutrients based on soil test and past

field historyUse disease-resistant cultivarsUse d se se es s cu v sManage insects and diseases

Maximize Crop Competitiveness

Rapid canopy cover will reduce weed growthGood growth conditionsVigorous varietiesgNarrower rows, more space between plants

in the rowin the rowStart from transplants

Maximize Crop Competitiveness

Supply water and nutrients near crop i i i iDrip irrigation

Band dry fertilizer, or supply in drip i i iirrigation

Nutrients in sync with crop needsSidedressing, periodic fertigation

MulchPlastic mulchBlackBlack Infra-red transmitting (IRT)

C idCover crop residueFall-plantedSpring-planted

Cultivation Blind cultivation Rotary hoe

Row-middles Sweepsp Rolling cultivator

Plastic edgeg

Cultivation can damage roots -Cultivation can damage roots so use shallow cultivation tools

Apply Herbicides Correctly Rate Timing Weed size or age Crop size or age Weather conditions Cultivation

I ti Incorporation Adjuvants Crop oil Concentrate UAN Nonionic surfactant Crop oil Concentrate, UAN, Nonionic surfactant

OrganicStale seedbedNo till into mow killed or crimpedNo-till into mow-killed or crimped

winter annual cover crop (rye, hairy t h)vetch)

Rotary hoe for direct-seeded cropsy pMulch in row

C lti tiCultivation

PumpkinsPumpkinsseeded on bare ground no herbicides

Stale seedbedprepare field 2 - 4 weeks in advancekill emerged weeds prior to or just afterkill emerged weeds prior to or just after

seeding (very shallow tillage, flaming)Rotary hoe, othersRotary hoe, othersCultivateHandweed and hoeHandweed and hoe

PumpkinsPumpkinsseeded into killed cover no herbicides

Choose planting arrangement and cultivar for rapid canopy closure

Kill cover at least 2 wks before seedingMowRoll and crimp

Minimize residue disturbance at plantingMinimize residue disturbance at plantingHandweed as needed

Preemergence Herbicides Registered for C bitCucurbits

Trade name Common nameDacthal DCPACommand clomazoneCurbit ethalfluralinSinbar Terbacil (WM ONLY)Sinbar Terbacil (WM ONLY)Prefar bensulideSandea halosulfuronSandea halosulfuronStrategy clomazone + ethalfluralinTreflanBrawl

TrifluralinS-metolachlor

Soil Applied HerbicidesApplied before or just after planting

cropcropKill weeds soon after they germinateMust be present in the soil where seeds

are germinatingg gEx: Curbit, Command, Brawl, Treflan

Curbit 3EC ethalfluralinWeeds: annual grasses, lambsquarters, nightshade,

pigweed, purslaneCrops: pumpkin, squash, muskmelon, watermelon,

cucumberRate: 3 4 pt /A Pkg: 5 6 A Cost: $18 24/ARate: 3 - 4 pt./A Pkg: 5-6 A Cost: $18 - 24/A Use: apply after seeding before crop emergence, or use

directed spray between rows; rain required to move into soil

Notes: do not incorporate, do not use under plastic mulch or row covers low margin of safetyor row covers, low margin of safety

Command 3ME clomazoneWeeds: annual grasses, velvetleaf, other BL but not

pigweeds C h k l t l bCrops: squash, muskmelon, watermelon, cucumber.

NOT Jack-o-Lantern pumpkinRate for melons: 0 4 - 0 67pt /A Pkg: 30 - 50 A Cost:Rate for melons: 0.4 - 0.67pt./A Pkg: 30 - 50 A Cost:

$5 - 9/A Use: apply before seeding or transplanting or after pp y g p g

seeding before crop emergenceNotes: 45-day PHI cucumbers and squash

Strategy ethalfluralin + clomazoneWeeds: annual grasses, lambsquarters, velvetleaf,

pigweed, C ki h k l t lCrops: pumpkin, squash, muskmelon, watermelon,

cucumberRate: 2 - 6 pt./A Pkg: 3 - 10 A Cost: $21 - 64/ARate: 2 6 pt./A Pkg: 3 10 A Cost: $21 64/A Use: apply after seeding before crop emergence, or use

directed spray between rows; rain required to move into isoil

Notes: do not incorporate, do not use under plastic mulch or row covers, low margin of safetyor row covers, low margin of safety

Treflan 4EC trifluralin

Weeds: annual grasses, lambsquarters, pigweed, purslane

C ki h k lCrops: pumpkin, squash, muskmelon, watermelon, cucumber

Rate: 1 - 2 pt./A Pkg: 10 - 20 A Cost: $3 - 5/ARate: 1 2 pt./A Pkg: 10 20 A Cost: $3 5/A Use: apply as directed spray between rows;

incorporate immediately N d d l i l h 30 dNotes: do not use under plastic mulch; 30-day

PHI; 60-day PHI for watermelon; granular formulations available

Sandea halosulfuronWeeds: pigweed, ragweed, velvetleaf, nutsedge,

lambsquarters (pre), morningglory (suppression)C ki i t h k l t lCrops: pumpkin, winter squash, muskmelon, watermelon,

cucumberRate: 0.5 - 1 oz./A Pkg: 10 - 20 A Cost: $21- 42/A Use: apply after seeding before crop emergence; apply before

transplanting and wait 7 days; for selected crops only apply post after crop has 3 to 5 leaves and before female flowers;pp y p p ;apply as directed spray to row middles

Notes: low margin of safety; 57-day PHI for melons; 30-day PHI for othersday PHI for others

Treflan 4EC trifluralin

Weeds: annual grasses, lambsquarters, pigweed, purslanep

Crops: pumpkin, squash, muskmelon, watermelon, cucumber

Rate: 1 - 2 pt./A Pkg: 10 - 20 A Cost: $3 - 5/A Use: apply as directed spray between rows;

incorporate immediatelyincorporate immediately Notes: do not use under plastic mulch; 30-day

PHI; 60-day PHI for watermelon; granularPHI; 60 day PHI for watermelon; granular formulations available

Brawl (metolachlor)-Weeds: annual grasses, nightshade, pigweed,

and nutsedgegCrops: pumpkin ONLYRate: 1 1 3 pt /A Pkg: 15 20 A Cost: $15Rate: 1 - 1.3 pt./A Pkg: 15 - 20 A Cost: $15-

20/A U l di t d t iddlUse: apply as directed spray to row middles,

leave 1 ft area over crop untreated, allow i i f 6” f d l t lminimum of 6” from seed or plant leaves

Crop Injury from Command -lclomazone

Foliar Applied HerbicidesKill weeds after they have emergedMay be taken up by leaves and in someMay be taken up by leaves and in some

cases roots of weedsSome may also be applied to the soilAdjuvants often used to promoteAdjuvants often used to promote

absorption by leavesE S d l h t P tEx: Sandea, glyphosate, Poast

Postemergence Herbicides RegisteredPostemergence Herbicides Registered for Cucurbits

Trade name Common nameRoundup glyphosateRoundup glyphosateGramoxone paraquatP t th diPoast sethoxydimSelect Max clethodimSandea halosulfuronAim carfentrazoneAim carfentrazone

Poast 1.5E sethoxydim

Weeds: grassesC iCrops: all cucurbitsRate: 1 - 1.5 pt./A Pkg: 5 - 8 A Cost: $9-14/A Use: apply to actively growing grass, include

1 qt. COC per acreNotes: 14 day PHI; maximum 3 pt./A per

season

Select clethodimWeeds: grassesCrops: all cucurbitspRate (2EC): 6 - 8 fl. oz./A Pkg: 16 - 21 A

Cost: $8-12/ACost: $8 12/A Use: apply to actively growing grass, include 1

qt. COC per acreqt. COC per acreNotes: 14 day PHI; maximum 1 qt./A per

seasonseason

Herbicides - Postemergence butHerbicides Postemergence but not over top of crop

Gramoxone paraquatp qRoundup glyphosateAim carfentrazoneAim carfentrazoneScythe pelargonic acid

Gramoxone Inteon paraquatWeeds: emerged annualsCrops: all cucurbitsRate (2L): 2 - 4 pt./A Use: apply before seeding or transplanting or after

seeding before crop emergenceseeding before crop emergenceNotes: restricted use pesticide; contact activity only

Roundup glyphosateWeeds: emerged annuals and perennialsCrops: all cucurbitsCrops: all cucurbitsRate (4 lb. ai/gal): 1 - 5 qt./A U l t l t 3 d b f diUse: apply at least 3 days before seeding

or transplanting, or apply between ith h d d hi ld drows with hooded or shielded sprayer

Notes: 14-day PHI; remove residue from plastic mulch before transplanting

Aim EC carfentrazone

Weeds: lambsquarters, morningglory, nightshade, velvetleaf, pigweedg , , p g

Crops: all cucurbitsRate: 0 5 2 fl oz /ARate: 0.5 - 2 fl. oz./A Use: apply before transplanting, or apply

b t ith h d dbetween rows with hooded sprayerNotes: use COC or NIS. Do not apply

before direct seeding.

Scythe pelargonic acidWeeds: emerged annualsCrops: all cucurbitsCrops: all cucurbitsRate: 2-10 gal./AUse: apply before planting, or after seedingUse: apply before planting, or after seeding

before crop emergence, or as a directed spray between rows

Notes: use 75 to 100 gals. total spray solution per acre; good coverage essential for control; contact activity only; only small weeds arecontact activity only; only small weeds are killed

Scythe on lambsquarterlambsquarter

 1 DAT 10%, 100 gpa 2WAT

Transplant, Plastic MulchPre-emergence herbicideUnder mulchUnder mulchRow middles only

N l ti h bi id f iddlNon-selective herbicide for row middles, hooded or shielded sprayer

Cultivation and handweedingPost-emergence broadleaf and/or grass

herbicide

Weed Control for Pumpkin (C. pepo)Weed Control for Pumpkin (C. pepo)

Brawl at 1 1 33 pts/A between hills or rows only Brawl at 1-1.33 pts/A between hills or rows only Strategy 3-5 pt/A PRE Curbit 3 pt/A PRE Sandea 0.5-0.75 oz + Poast or Select as directed

spray Other treatments include choices of paraquat,Other treatments include choices of paraquat,

glyphosate, Aim, Scythe for pre plant, preemergence and row middlespreemergence and row middles

PumpkinsPumpkinsseeded on bare ground

Stale seedbed prepare field 2 - 4 weeks

in advancekill d i t j t kill weeds prior to or just after seeding (very shallow tillage or non-gselective herbicide)

Preemergence herbicide f iafter seeding Strategy

PumpkinsPumpkinsseeded on bare ground, cont.Depending on weed species and

pressurepSandea or Non-selective and/or PoastCultivationCultivationRow-middle application of Curbit or

T flTreflanHandweeding

No-till, Direct SeedBurndown before seedingPre-emergence herbicidePre emergence herbicideNon-selective herbicide for row

middles hooded or shielded sprayermiddles, hooded or shielded sprayerPost-emergence broadleaf and/or grass

h bi idherbicideHandweeding

Pumpkinsseeded into killed coverseeded into killed coverKill cover at least 2 wks before seedingKill cover at least 2 wks before seedingAfter seeding apply preemergence

herbicide and if needed non-selectiveherbicide and if needed non-selective herbicide for emerged weeds

St t l h tStrategy, glyphosate

PumpkinsPumpkinsseeded into killed coverDepending on weed pressureSandea and/or PoastSandea and/or PoastRow-middle hooded sprayer p yapplication of glyphosate or AimRow-middle application of CurbitRow-middle application of CurbitHandweeding

Sandea on Pumpkin and SquashSandea on Pumpkin and Squash Pumpkin is more tolerant than squash to Pumpkin is more tolerant than squash to

Sandea PRE and POST Maxima squash appear to be most sensitive Maxima squash appear to be most sensitive Do not apply more than 0.5 oz Sandea PRE or

POSTPOST Do not use NIS POST Use directed spray POST Heavy rain will increase injury

Preemergence Weed ControlgIn Pumpkin 3WAT

Weedy Ck Strategy + Sandea Sandea Sandea4 pts + 1/2 oz 1/2 oz 2/3 oz

Postemergence Weed Control in Pumpkin 3 Weeks after Post

WeedyCheck

SandeaPre 1 oz

Sandea 1/2 oz Sandea 2/3 ozPost Post

Pre 1 oz

Weed Control for Seeded Melons and C b B d ( l ti )Cucumber – Bareground (no plastic)

Curbit 2 pt + Command 0.67 pt PRE after seeding. Apply water to incorporate; follow with Sandea 0.5 oz + Poast 1 pt (or Select) broadcast at 2-5 leaf stage (before

vining)vining)

or

Strategy 4-6 pt broadcast after seeding; followwith Sandea 0.5 oz + Poast 1 pt (or Select) just before i ivining

or

PPI Prefar 6 qt before seeding; follow with Sandea 0 5 oz + PPI Prefar 6 qt before seeding; follow with Sandea 0.5 oz + Poast 1 pt (or Select) just before vining

Weed Control for Transplanted pMelons on Plastic Mulch (Option 1)

Sandea 0.5 oz to soil before laying plastic mulch; wait 7 days to plant melons; Sandea 0.5 oz + ; y p ;Poast 1 pt to soil between plastic before vines grow beyond plasticbeyond plastic

Prefar 3 qt, incorporate before laying plastic; SandeaPrefar 3 qt, incorporate before laying plastic; Sandea 0.5oz + Poast 1 pt (or Select) broadcast just before vining

Weed Control for Transplanted pMelons on Plastic Mulch (Option 2)

Lay plastic and plant melons; apply Curbit 2 pt + Command 0.67 pt to soil between plastic after TP p p

Lay plastic and plant melons; Treflan 1 qt Lay plastic and plant melons; Treflan 1 qt between rows of plastic – water in; followed by S d 0 5 + P t 1 t ( S l t) di t dSandea 0.5 oz + Poast 1 pt (or Select) directed between rows of plastic before vining

W t l W d C t lWatermelon Weed ControlAll t t t l b l d f k l l b l dAll treatments labeled for muskmelon are labeled for watermelon

Sinbar is labeled for watermelon; 2-4 oz/ac;PRE after seeding or before TP; it may beapplied under plastic or to row middles Doapplied under plastic or to row middles. Donot apply over the top of plants. 70 day PHI

Important Considerations about Weed Control in Cucurbits

Weed control is essential for effective di t l d f hi h i lddisease control and for high yields

Cucurbits are sensitive to many of the h bi id i t dherbicides registered

Command is not registered on jack-o-l t kilantern pumpkins

ALS-inhibitors (e.g., Sandea) accumulate i th il d b t i t bitin the soil and can be toxic to cucurbits

Important Considerations Plant crops so that you can cultivate or

disk between rows Leave spray aisles for driving in the

fieldfield Use drop nozzles to keep Sandea off

crop leavescrop leaves Refer to ID-56 for crop production and

d t d tiweed management recommendations