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Publication #HS189

Weed Control in Cole or Brassica Leafy Vegetables (Broccoli, Cabbage, Cauliflower, Collard, Mustard, Turnip, and Kale)1

Peter J. Dittmar and Nathan S. Boyd2

The Brassica leafy vegetables (cole crops) range from major crops such as cabbage to very minor ones, including mustard and rape greens. Optimal production of these crops depends on successful weed control. Weeds reduce yields by direct competition for nutrients, water, and light. Weed control is especially important early in the season when weed competition can substantially reduce vigor, uniformity, and overall yield. In Florida, there are a large number of weeds that are also in the Brassicaceae (mustard) family. These weeds in and around the field can harbor insects and disease pathogens that can invade or spread to the crop soon after planting.

Management Practices

Effective weed control should include a combination of management practices designed to suppress weeds during the entire year. These practices include crop rotation, cover cropping, high planting density, mulching, cultivation, flooding, and herbicide use. The amount and timing of cultivation has been shown to be very important. Cultivating more than one or two times early in the season reduces head quality and yield in cabbage.

The most effective weed management strategies must be made long before the crop is planted.

Planting Dates

Planting dates can have an effect on weed management in a given region. When hard-to-control winter or summer annuals may be present in a field it is best to plant the crop when the specific weed or weeds are not growing. Cabbage is much more competitive against weeds when grown under optimal conditions. For example, during the warmer part of the spring and fall seasons, wild radish densities up to 16 plants/meter will not reduce cabbage yields but during the cooler part of the season, one wild radish plant/meter will reduce yields significantly.

Perennial weeds such as nutsedge should be controlled during noncrop periods. Detailed weed maps kept over time will help improve management decisions such as when to plant and which herbicides are the most effective.

The crop variety and size should also be considered when selecting a herbicide. For example, when using Dual or Goal® in cabbage growers must plan on having at least 5-week-old transplants in 1-inch cells. Use of younger transplants in smaller cells may result in phytotoxicity to the young plants.

Labels and Crop Groups

The labels for Dual on cabbage are third-party registrations by TPR, Inc., Orlando. The label is issued by TPR, Inc. and is valid only when a grower indemnification agreement is signed.

The term “Brassica (cole) leafy vegetables” refers to a crop group set up by the EPA to allow tolerances to be established for the whole crop group. The group is separated into two subgroups: head and stem Brassica and leafy Brassica greens. The head and stem Brassica subgroup includes broccoli, Chinese broccoli, Brussels sprouts, cabbage, Chinese cabbage (napa), Chinese mustard cabbage, cauliflower, cavalo broccoli, and kohlrabi. The leafy Brassica greens subgroup includes broccoli raab, Chinese cabbage (bok choy and chilhilli), collards, kale, mizuna greens, mustard spinach, rape greens, and turnip greens. If the total crop group is not stated, then the product may only be used for those commodities listed on the label.

If a label states directions for cabbage, then it may only be used on cabbage; if it states cabbage and tight-headed Chinese cabbage, it may also be applied to the napa types of Chinese cabbage. The chilhilli types are classified as loose headed, as is bok choy.

Table 1 lists the herbicides that are suggested for use on the various crops before crop seed emergence or transplanting in Florida. Table 2 includes chemical weed control that can be used after crop seed emergence or after transplanting. Before using an herbicide, read the label carefully and follow all directions and restrictions.

Tables

Table 1. 

Preemergence or pretransplant herbicides for weed control in broccoli, cabbage, cauliflower, collards, mustard, turnips, and kale.

Common name

lb. a.i./A

Trade name

amount of product/A

MOA code

Crops

Weeds controlled / remarks

Bensulide

5–6

(Prefar®) 4E

5–6 qt.

8

Head and stem and leafy Brassica

Annual broadleaf and grass weeds. Mechanically incorporate 1–2 in. or irrigate 2–4 in. deep within 36 hours.

Carfentrazone

Up to 0.031

(Aim®) 2 EC

(Aim®) 1.9 EW

Up to 2 fl. oz.

14

Head and stem and leafy Brassica

Apply as a preplant burn down for emerged broadleaf weeds. Use crop oil concentrate, methylated seed oil, or nonionic surfactant at recommended rates. Maximum rate of 0.096 lb. a.i./A per season. No pretransplant interval

Clomazone

0.25

0.25-10.5

(Command®) 3ME

0.67 pt. direct seeded

0.67-1.0 pt. transplanted

13

Broccoli, Brussels sprouts, cauliflower, cabbage, and Brassica leafy vegetables

Broadleaf and grass weeds. Can be preplant incorporated. If weeds have emerged they must be cultivated or weeded before application.

DCPA

4.5–10.5

(Dacthal®) 75 WP

6–14 lb.

3

Broccoli, Brussels sprouts, cauliflower, cabbage, and leafy Brassica vegetables

Annual grass and broadleaf weeds. Can be preplant incorporated. If weeds have emerged, they must be cultivated or weeded before application.

Glyphosate

0.3–1.0

(Various formulations)

9

Head and stem and leafy Brassica vegetables

Actively growing broadleaf and grass weeds. Use as a preplant burndown.

Oxyfluorfen

0.25–0.5

(Goal® 2XL) 2 EC

1–2 pt.

(Galigan®) 2 E

1–2 pt.

(GoalTender®, Galigan® H2O) 4 E

0.5-1 pt.

14

Broccoli, cabbage, cauliflower

Certain annual broadleaf weeds. Transplants less than 5 weeks old or in containers less than 1 inch square may result in more crop injury. Injury occurs as leaf cupping or crinkling. DO NOT apply in fields where acetanilide herbicides (Dual Magnum®, Lasso®, or Ramrod®) have been applied in the same growing season.

Paraquat

0.5–1.0

(Gramoxone® SL) 2.0 SL

2.0–4.0 pt.

(Firestorm®) 3.0 SL

1.3–2.7 pt.

22

Broccoli, cabbage, cauliflower, cavalo broccoli, Chinese cabbage, turnip

Emerged broadleaf and grass weeds. Use as a preplant burndown. Crop plants that have emerged will be injured.

Pelargonic acid

(Scythe®) 4.2 EC

3%–10% v/v

27

Broccoli, cabbage, cauliflower, collards, kale, mustard/turnip greens

Emerged broadleaf and grass weeds. Use as a preplant burndown.

Trifluralin

0.5–0.75

(Treflan® HFP, Trifluralin, Trifluralin HF) 4 EC

1.0–1.5 pt.

(Treflan®) 4 L

1.0–1.5 pt.

3

Broccoli, Brussels sprouts, cabbage, cauliflower

Annual broadleaf and grass weeds. Incorporate or irrigate 4 inches within 8 hours. Results in Florida are erratic on soils with low organic matter and clay content.

Table 2. 

Herbicides for weed control postemergence or post-transplant weed control in cole crops

Common name

lb. a.i./A

(Trade name)

amount of product/A

MOA

code

Crops

Weeds controlled / remarks

Carfentrazone

Up to 0.031

(Aim®) 2.0 EC

(Aim®) 1.9 EW

Up to 2 fl. oz.

14

Head and stem and leafy Brassica

Emerged broadleaf weeds. Apply with a hooded sprayer to row middles. Do not exceed 4.1 fl. oz./A in season as a row middle application. PHI 0 days.

Clethodim

0.09–0.13

(Select®) 2 EC

6–8 fl. oz.

(Select Max®) 1 EC

9–16 fl. oz.

1

Head and stem and leafy Brassica

Emerged grass weeds. Include crop oil concentrate at 1% v/v in finished spray volume. Head & stem Brassica PHI 30 days. Leafy Brassica PHI 14 days.

Clopyralid

0.09–0.19

(Stinger®) 3 EC

0.25–0.5 pt.

4

Cabbage, Chinese cabbage (bok choy, napa), Chinese mustard cabbage

Broadleaf weeds. Do not apply more than 0.5 pt./A per year. Check plant-back dates. PHI 30 days.

DCPA

4.5–10.5

(Dacthal®) 75 WP

6–14 lb.

3

Broccoli, Brussels sprouts, cauliflower, cabbage, and Brassica leafy vegetables

Broadleaf and grass weeds. Spray over transplants without injury. If weeds have emerged, they must be cultivated or weeded before application. Can be preplant incorporated.

Glyphosate

0.3–1.0

(Various formulations)

9

Head and stem and leafy Brassica

Broadleaf and grass weeds. Use a hooded sprayer and direct to row middles only.

Napropamide

2

(Devrinol®) 50 DF

4 lb.

15

Broccoli, Brussels sprouts, cabbage, cauliflower

Apply to transplanted crops only. Within 24 hours of application, 2–4 inches of irrigation or rainfall are necessary. Do not exceed 4 lb./A per crop cycle.

Pelargonic acid

(Scythe®) 4.2 EC

3%–10% v/v

27

Broccoli, cabbage, cauliflower, collards, kale, mustard/turnip greens

Emerged broadleaf and grass weeds. Apply as hooded spray to row middles only. Include a residual herbicide to broaden spectrum of weed control.

Pendimethalin

0.48-0.71

(Prowl H2O) 3.8

1.0-1.5 pt.

3

Broccoli, Brussels sprouts, cabbage, cauliflower

Broadleaf and grass weeds. Apply after crop emergence (2- to 4- leaf stage) or after transplanting (1 to 3 days) and prior to weed emergence. Direct the spray to the base of the plant to limit contact to the foliage. PHI 60 days for broccoli. PHI 70 days for cabbage and other head & stem brassica.

Pendimethalin

1

(Satellite Hydrocap)

1.0-1.5 pt.

3

Broccoli, Brussles sprouts, cabbage, cauliflower, Chinese broccoli, napa cabbage, Chinese mustard cabbage, Cavalo Broccoli, Kohlrabi

Broadleaf and grass weeds. Preplant or postemergence-directed application. NOT direct-seeded. Post-transplant application to the base of the plant. PHI 60 days for broccoli. PHI 70 days for cabbage and other head and stem brassica.

Pendimethalin

1

(Satellite Hydrocap)

2.1 pt.

3

Mustard greens, broccoli raab, bok choy, collards, kale, mizuna, mustard spinach, rape greens, turnip greens (leaves only)

Broadleaf and grass weeds. Apply to direct seeded or transplanted crops at the 4- to 5 leaf stage. Do not apply in turnip greens if the roots will be used for food. PHI 21 days.

S-metolachlor

Mineral

0.64–1.91

Muck

1.91

(Dual Magnum®) 7.62 EC

Mineral

0.67–2.0 pt.

Muck

2.0 pt.

15

Head and stem Brassica

Annual broadleaf and grass control. Apply immediately after planting. Label is a third-party registration by TPR, Inc., and grower must sign an indemnification agreement. Use higher rate on fine-textured soils or soils high in organic matter. Do not apply more than 1.91 lb. a.i./A of Dual Magnum® per crop on sandy soils. Chinese varieties are more sensitive to Dual Magnum® injury. PHI 60 days.

S-metolachlor

Mineral

0.76–1.26

Muck

1.91–3.82

(Dual Magnum®) 7.62 EC

Mineral

0.80–4.0 pt.

Muck

1.82-3.64 pt.

15

Direct-seeded cabbage

Annual broadleaf and grass weeds. Label is a third-party registration by TPR, Inc., and grower must sign an indemnification agreement. May be applied preemergence or postemergence to direct-seeded tight-headed cabbage. Preemergence application should be made at least 20 days after seeding. Apply once per crop season. At higher rates, anticipate delayed maturity.

Sethoxydim

0.28

(Poast®) 1.5 EC

1.5 pt.

1

Broccoli (including Chinese and raab), Brussels sprouts, cabbage (bok choy, Chinese mustard, napa), cauliflower, collards, kale, kohlrabi, mustard/rape greens

Annual and perennial grass weeds. Include a crop oil concentrate or methylated seed oil in spray solution. Maximum rate or 3.0 pt./A per season. PHI 30 days.

Table 3. 
   

Timing and application location relative to crop

 

Timing relative to weeds

Weeds controlled / suprressed

Crops

Common name

Trade name

Before seeding

After seeding before emergence

Before transplanting

Postemergence

Postemergence –

row middles only

Incorporated

Preemergence

Postemergence

Annual grasses

Broadleaves

Perennial Sedges

Broccoli

Brussels sprouts

Cabbage

Cauliflower

Chinese cabbage (napa)

Kohlrabi

Bensulide

Prefar®

X

 

X

   

X

X

 

X

X

 

X

X

X

X

X

X

Carfentrazone

Aim®

X

     

X

       

X

 

X

X

X

X

X

X

Clethodim

Select Max®

     

X

     

X

X

   

X

X

X

X

X

X

Clomazone

Command®

   

X

   

X

X

 

X

X

 

X

X

X

X

   

Clopyralid

Stinger®

     

X

         

X

     

X

 

X

 

DCPA

Dacthal®

   

X

X

 

X

X

 

X

X

 

X

X

X

X

   

Glyphosate

Roundup®

X

 

X

       

X

X

X

X

X

X

X

X

X

X

Napropamide

Devrinol®

     

X

 

X

X

 

X

X

 

X

X

X

X

   

Oxyfluorfen

Goal®, Galigan®

   

X

   

X

X

X

X

X

 

X

 

X

X

   

Paraquat

Gramoxone ®

X

 

X

       

X

X

X

 

X

 

X

X

X

 

Pelargonic acid

Scythe®

X

 

X

 

X

   

X

X

X

 

X

 

X

X

   

Pendimethalin

Prowl H2O®,

Satellite Hydrocap®

   

X1

X

 

X

X

 

X

X

 

X

X

X

X

X

X

S-Metolachlor

Dual Magnum®

     

X

 

X

X

 

X

X

X

X

X

X

X

X

X

Sethoxydim

Poast®

     

X

     

X

X

   

X

X

X

X

X

X

Trifluralin

Treflan®

X

 

X

   

X

X

 

X

X

 

X

X

X

X

   

1 Not all brands are labeled for this use pattern. Consult labels before purchasing or application.

Table 4. 

Herbicide timing in leafy brassica vegetable crops.

   

Timing and Application Location Relative to Crop

 

Timing Relative to Weeds

Weed Groups Controlled

Crops

Common Name

Trade Name

Before seeding

After seeding, before emergence

Before transplanting

Postemergence

Postemergence –row middle

Incorporated

Preemergence

Postemergence

Annual grasses

Broadleaves

Perennial sedges

Broccoli raab

Chinese cabbage (bok choy)

Collards

Kale

Mustard greens

Turnip greens

Bensulide

Prefar®

X

 

X

   

X

X

 

X

X

 

X

X

X

X

X

X

Carfentrazone

Aim®

X

     

X

       

X

 

X

X

X

X

X

X

Clethodim

Select Max®

     

X

     

X

X

   

X

X

X

X

X

X

Clomazone

Command®

   

X

   

X

X

 

X

X

 

X

X

X

X

X

X

Clopyralid

Stinger®

     

X

         

X

   

X

       

DCPA

Dacthal®

   

X

X

 

X

X

 

X

X

 

X

X

X

X

X

X

Glyphosate

Roundup®, others

X

 

X

       

X

X

X

X

X

X

X

X

X

X

Oxyfluorfen

Goal®, Galigan®

   

X

   

X

X

X

X

X

             

Paraquat

Gramoxone ®

X

 

X

       

X

X

X

   

X

     

X

Pelargonic acid

Scythe®

X

 

X

 

X

   

X

X

X

     

X

X

X

X

Pendimethalin

Prowl H2O®

Satellite Hydrocap®

   

X1

X

 

X

X

 

X

X

 

X

X

X

X

X

X

Sethoxydim

Poast®

     

X

     

X

X

   

X

X

X

X

X

X

1 Not all brands are labeled for this use pattern. Consult labels before purchasing or application.

Footnotes

1.

This document is HS189, one of a series of the Horticultural Sciences Department, UF/IFAS Extension. Original publication date January 1996. Revised August 2003, October 2006, March 2010, August 2012, and December 2015. Visit the EDIS website at http://edis.ifas.ufl.edu.

2.

Peter J. Dittmar, assistant professor; and Nathan S. Boyd, Gulf Coast Research and Education Center; UF/IFAS Extension, Gainesville, FL 32611.

The use of trade names in this publication is solely for the purpose of providing specific information. UF/IFAS does not guarantee or warranty the products named, and references to them in this publication do not signify our approval to the exclusion of other products of suitable composition. All chemicals should be used in accordance with directions on the manufacturer's label. Use pesticides safely. Read and follow directions on the manufacturer's label.


The Institute of Food and Agricultural Sciences (IFAS) is an Equal Opportunity Institution authorized to provide research, educational information and other services only to individuals and institutions that function with non-discrimination with respect to race, creed, color, religion, age, disability, sex, sexual orientation, marital status, national origin, political opinions or affiliations. For more information on obtaining other UF/IFAS Extension publications, contact your county's UF/IFAS Extension office.

U.S. Department of Agriculture, UF/IFAS Extension Service, University of Florida, IFAS, Florida A & M University Cooperative Extension Program, and Boards of County Commissioners Cooperating. Nick T. Place, dean for UF/IFAS Extension.