NOTE: For the disease control products listed below, one product trade name and formulation is provided for each active ingredient (common name) as an example of rates, preharvest interval (PHI), restricted entry interval (REI), and special instructions. In many cases, there are other products available with the same active ingredient. Please see Table 25 and Fungicides and Bactericides Alphabetical Listing by Trade Name for more information on products with the same active ingredients.
The symbol OG indicates a product is listed by the Organic Materials Review Institute (OMRI) as approved for use in organic production. See Organic Certification section for more detail.
Okra is a tropical annual with a wide range of adaptation; it is very sensitive to cold temperatures and frost. Do not plant until soil temperatures have warmed in the spring.
Cercospora Leaf Spots (Cercospora species)
The pathogens survive on infected plant debris; remove and destroy diseased plant material. Plow crop debris under after harvest to speed up decomposition.
azoxystrobin plus difenoconazole (Quadris Top): 8-14 fl oz/A; PHI 0d, REI 12h, Groups 11 & 3.
chlorothalonil (Bravo Weather Stik): 1.5 pt/A; PHI 3d, REI 12h, Group M5.
chlorothalonil plus cymoxanil (Ariston): 2-4.4 pints/A; PHI 3d, REI 12, Groups M3 & 27.
copper hydroxide (Kocide 3000): 0.75 to 1.75 lb/A; PHI 0d, REI 48h, Group M1. Do not apply in a spray solution with a pH less than 6.5 or tank mix with Aliette.
tebuconazole (Orius 3.6F): 4 to 6 fl oz/A; PHI 3d, REI 12h, Group 3.
sulfur (Microthiol DisperssOG): 3.0 to 10.0 lb/A; PHI 0d, REI 24h, Group M2.
Damping-off (Pythium and Rhizoctonia solani)
Damping-off diseases are favored by cool, cloudy weather, wet soils, high humidity, compacted soils, and overcrowding. Sterilize used pots and trays to raise seedlings. Use a heating pad under trays to warm soil to 75-90°F for indoor plant production. Avoid excessive irrigation, improve soil drainage, and relieve soil compaction. Remove and destroy affected plants and avoid transplanting diseased plants into the field. Seed treatments with biological control agents or fungicides are useful.
azoxystrobin (Quadris): 0.40 to 0.80 fl oz/ 1000 row feet; PHI 0d, REI 4h, Group 11.
mefenoxam (Apron XL): 0.16 to 0.64 fl oz/100 lbs seed; REI 48h, Group 4. Seed treatment.
phosphorous acid (Fosphite): 1.0 to 3.0 qt/in a minimum of 20 gal. water/A; PHI 0d, REI 4h, Group 33. Do not apply to plants that are heat or moisture stressed. Copper phytotoxicity may occur if applied in alteration with copper.
thiram (Thiram 42 S): 6.0 lb/100 lb seed; REI 12h, Group M3.
Fusarium and Verticillium Wilts
Avoid planting in fields where these diseases are present. Rotate with non-solanaceous crops. Plant resistant varieties, if available. Consider soil fumigation. Soil solarization, fallowing, flooding, and biofumigation with brassica green manures may reduce soil populations of these pathogens. See Soil Fumigation Outdoors in the Disease Management section.
Trichoderma asperellum, T. gamsii (Bioten 2.0OG): See label for in-furrow, drench, and broadcast rates; REI 1h, Group NC.
Fruit Rot (Choanephora spp.)
Choanephora is a soilborne pathogen that attacks senescent blossoms and grows into the fruit. No fungicides are labeled for control. Improve air circulation by proper plant spacing.
Powdery mildew (Erysiphe cichoracearum)
Maintain plant health by adequate fertilization as nutrient stressed plants are more susceptible to infection.
azoxystrobin (Quadris): 6.0 to 15.5 fl oz/A; PHI 0d, REI 4h, Group 11.
copper hydroxide (Kocide 3000): 0.75 to 1.75 lb/A; PHI 0d, REI 48h, Group M1. Do not apply in a spray solution with a pH less than 6.5 or tank mix with Aliette.
sulfur (Microthiol DisperssOG): 3.0 to 10.0 lb/A; PHI 0d, REI 24h, Group M2.
Nematodes
Nematode control is very important for okra production. Fumigate fields in the fall. See Soil Fumigation Outdoors in the Disease Management Section. Rotate with corn.
Yellow Vein Mosaic Virus (YVMV)
YVMV is the most important virus disease of Okra and it severely reduces growth and yield as well as causing fruit deformity. It is spread by whiteflies. There are no cures or chemical treatments for plant viruses. Remove and destroy affected plants. Plant resistant varieties. Control whiteflies to reduce disease incidence.