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Publication #HS192

Weed Management in Okra1

Peter J. Dittmar and William M. Stall2

Okra is grown throughout the state during the warm season. During this time, warm-season annual weeds can be a serious problem in the field.

Herbicides labeled for use within the plant row are severely limited (see Table 1). For this reason, weeds should be controlled before planting or before okra seed emergence. A broadcast application of carfentrazone (Aim®), glyphosate (Roundup®, etc.), paraquat (Gramoxone Inteon®), and pelargonic acid (Scythe®) can be applied before okra seed emergence. These herbicides do not control weed seeds that have not germinated at time of application.

For preemergence weed control in the planting row, trifluralin (Treflan®, etc.) is the only preplant incorporated treatment now labeled in okra. Flumioxazin (Chateau®), lactofen (Cobra®), and mesotrione (Callisto®) are restricted to row middles only.

Cultivation is commonly used in okra, either with sweeps or rolling cultivators. Care should be taken not to throw soil too far up on the okra stems. This practice can increase stem rot and decay.

In some areas of the state, okra has been planted as a second crop behind mulched vegetables after the mulch has been removed. This production practice has been quite successful, but okra must not be planted as a second crop into soil containing residual herbicides from the first crop that are phytotoxic to okra. Read the label of each herbicide to find out the length of time that must elapse before nonlabeled crops may be planted in the field.

Tables

Table 1. 

Chemical weed controls in okra

Active ingredient lb. a.i./A

Trade name formulation/A

Weeds controlled/remarks

PREPLANT / PREEMERGENCE

Carfentrazone

Up to 0.31

(Aim®) 2 EC or 1.9 EW

Up to 2 fl. oz.

Emerged broadleaf weeds. Apply as a preplant burndown for emerged broadleaf weeds. Use crop oil concentrate or nonionic surfactant at recommended rates. Maximum rate of 0.096 lb. a.i./A. per season. May be tank mixed with other herbicides.

Flumioxazin

Up to 0.128

(Chateau®) 51 WDG

Up to 4 oz.

Annual broadleaf and grass weeds. Apply to row middles of raised plastic-mulched beds that are at least 4 in. higher than the treated row middle and 24 in. bed width. Registration is through Third-Party Registration, Inc. (TPR, Inc.). Use without a signed authorization and waiver of liability is a misuse of the product. Tank mix with a burndown herbicide to control emerged weeds.

Glyphosate

0.3–1.0

(Various formulations)

Emerged broadleaf and grass weed control. Apply as a preplant burndown for emerged weeds. Read label for amount of formulation allowed.

Lactofen

0.25–0.5

(Cobra®) 2 EC

16–32 fl. oz.

Broadleaf weed control. Apply to row middles only with a shielded or hooded sprayer. A minimum of 24 fl. oz./A is required for residual control. Add a crop oil concentrate or nonionic surfactant for control of emerged weeds. Registration is through TPR, Inc., and a copy of the label must be on hand at time of application. Preharvest interval (PHI) 30 days.

Mesotrione

0.19

(Callisto®) 4 L

6 fl. oz.

Certain broadleaf and grass weeds. Apply to row middles only. Leave 1 ft. untreated area or 6 in. on either side of the plant row. Injury risk is greatest on coarse-textured soils (sand, sandy loam, or loamy sand). Apply as one preemergence application OR one postemergence application. Callisto® causes whitening of okra.

Paraquat

0.5 – 1.0

(Gramoxone Inteon®) 2 SL

2.0–4.0 pt.

Emerged broadleaf and grass weed control. Apply one application before crop emergence. Do not exceed 8 pt./A per season.

Pelargonic acid

(Scythe®) 4.2 EC

3%–10%

Broadleaf and grass weed control. Scythe® is a contact, nonselective herbicide with no residual activity. May be tank mixed with trifluralin for soil residual activity. Consult label for rates and other information.

Prometryn

0.75 – 1.5

(Caparol®) 4 L

1.5-3.0 pt.

Apply after planting, but before crop emergence. Apply as one PRE application at 3 pt. or 1 PRE application at 1.5 pt. followed by one POST-directed application at 1.5 pt. Do not exceed 3 pt./A per crop cycle.

Trifluralin

0.5–0.75

(Treflan®, Trifluralin) 4EC

0.5–1.5 pt.

(Treflan®, Trifluralin) 10G

5–7.5 lb.

Annual broadleaf and grass weeds. Incorporate 4 in. or less within 8 hours. Results in Florida are erratic in soils with low organic matter and clay contents. Note precautions against planting nonregistered crops within 5 months.

POSTEMERGENCE

Carfentrazone

Up to 0.31

(Aim®) 2 EC or 1.9 EW

Up to 2 fl. oz.

Emerged broadleaf weeds. Apply to row middles only with a hooded sprayer. Maximum rate of 0.096 lb. a.i/A per season. Rates apply to mineral and muck soils. Use crop oil concentrate or nonionic surfactant at recommended rates. PHI 0 days.

Glyphosate

0.3–1.0

(Various formulations)

Emerged broadleaf and grass weeds. Apply to row middles only with a hooded sprayer. PHI 14 days.

Halosulfuron

0.024–0.05

(Sandea®) 75 WG

0.5–1.0 oz.

Broadleaf and purple/yellow nutsedge control. Apply to row middles of direct-seeded or transplanted okra. If plastic is used, prevent herbicide contact with the plastic. Do not apply more than 2 oz./A per 12-month period. PHI 30 days.

Lactofen

0.25–0.5

(Cobra®) 2 EC

16–32 fl. oz.

Broadleaf weed control. Apply to row middles only with a shielded or hooded sprayer. A minimum of 24 fl. oz./A is required for residual control. Add a crop oil concentrate or nonionic surfactant for control of emerged weeds. One POST application may be made per growing season at 18 days after transplanting. Cobra® contacting green foliage or fruit can cause excessive injury. Drift of Cobra®-treated soil particles onto plants can cause contact injury. Registration is through TPR, Inc., and a copy of the label must be on hand at time of application. PHI 30 days.

Lactofen

0.25 – 0.5

(Cobra®) 2 EC

16 – 32 fl. oz.

Broadleaf weed control. Apply to row middles only with a shielded or hooded sprayer. A minimum of 24 fl. oz./A is required for residual control. Add a crop oil concentrate or nonionic surfactant for control of emerged weeds. One POST application may be made per growing season at 18 days after transplanting. Cobra® contacting green foliage or fruit can cause excessive injury. Registration is through Third Party Registration, Inc. and a copy of the label must be on hand at time of application. PHI 30 days.

Mesotrione

0.09

(Callisto®) 4 L

3 fl. oz.

Broadleaf and grass control. Direct spray with hooded sprayer to minimize contact with okra plants. Okra must be at least 3 in. tall. Use a nonionic surfactant. Injury risk is greatest on coarse-textured soils (sand, sandy loam, or loamy sand). Apply as one preemergence application OR one postemergence application. PHI 28 days.

Paraquat

0.5–1.0

(Gramoxone Inteon®) 2 SL

2.0 pt.

Emerged broadleaf and grass weed control. Apply to row middles only and do not allow contact with okra plants. Limit of two applications after crop emergence. Do not exceed 8 pt./A per season. PHI 60 days.

Prometryn

0.75

(Caparol®) 4 L

1.5 pt.

Apply 1 postemergence application directed to the base of the crop. If a PRE application was made do not exceed 3 pt./A. PHI 14 days.

Pelargonic acid

(Scythe®) 4.2 EC

3%–10%

Broadleaf and grass weed control. Apply to row middles only with shielded sprayer.

Sethoxydim

0.19–0.28

(Poast®) 1.5 EC

1.0–1.5 pt.

Grass weed control. Efficacy is decreased if grass weeds are under stress. Include a crop oil concentrate or methylated seed oil in the spray. PHI 14 days.

Footnotes

1.

This document is HS192, one of a series of the Horticultural Sciences Department, UF/IFAS Extension. Original publication date March 1999. Revised October 2014. Visit the EDIS website at http://edis.ifas.ufl.edu.

2.

Peter J. Dittmar, assistant professor, and William M. Stall, emeritus professor, Horticultural Sciences Department, 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.