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, days to harvest (dh), REI, and special instructions. In many cases, there are other products available with the same active ingredient. Please see Table 28 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 details.
PESTICIDE USE IN GREENHOUSES AND HIGH TUNNELS:
Pesticides can be used on high tunnel and greenhouse crops if: 1) the crop and pest/disease is on the label, AND the products specifically says it can be used in the greenhouse; OR 2) the crop and pest/disease is on the label, AND the product is ‘silent’ about use in the greenhouse in the greenhouse. Products that specifically prohibit greenhouse use cannot be used in greenhouses or high tunnels regardless of the crops or pests/diseases listed on the label.
Purchase disease-free seed. Use resistant varieties where feasible. Promptly remove any stock plants that are diseased or low in vigor. Use separate greenhouses for herb production and keep stock plants separate from production areas. There are few fungicides or bactericides registered for herbs.
Bacterial Leaf Spot (Pseudomonas cichorii )
Disinfect all benches, equipment, and pots. Purchase culture-indexed plants and disease-free seed. Avoid overhead irrigation. Discard infected plants. Clean production areas thoroughly after harvest as bacteria can survive in dead leaves.
Botrytis blight and stem canker (Botrytis cinerea)
Management of environmental conditions such as temperature, relative humidity and duration of leaf wetness is vital to Botrytis control. Control weeds and remove plant debris between crops and during production. Provide good air circulation and reduce humidity within the plant canopy by proper plant spacing, plant height, and fertility. Water in the morning, never late in the day.
cyprodinil plus fludioxonil (Switch 62.5 WG): 11 to 14 oz/A. (7 dh, REI 12h, Groups 9 & 12). Do not make more than 2 consecutive applications.
Ulocladium oudemansii (BotryStopOG): 2-4 lbs/A. (REI 4h, Group not applicable). Begin application when conditions are conducive to disease development.
Damping-off, Crown and Root Rot (Pythium spp., Rhizoctonia spp., Fusarium spp. & Phytophthora spp.)
Use pasteurized soil or soil-less mixes for transplant production. Disinfect all flats, pots, and tools. Use bottom heat to promote rapid seed germination. Avoid over-watering, over-fertilizing, and overcrowding. Promptly rogue out infected plants. Manage fungus gnats and shoreflies.
mefenoxam (Ridomil Gold SL): 0.5 to 1.0 pt/A. (21 dh, REI 48h, Group 4). Pythium and Phytophthora ONLY.
fludioxonil (Maxim 4FS): 0.08 to 0.16 oz/00 lb seed. (REI 12h, Group 12). For protection against seed-borne and soil-borne fungi. Does not control Pythium and Phytophthora.
potassium phosphite (K-Phite): 1 to 4 qt/A. (dh, REI, Group). Apply in a minimum of 20 gal water/A.
Downy Mildew (Peronospora belbarhii)
Downy Mildew of basil is rapidly becoming a major production problem. Start with certified, disease-free seed. Scout crops regularly and promptly remove and destroy infected plants. Reduce leaf wetness periods by plant spacing, improving air circulation, and watering when plants will dry quickly. In the greenhouse, use a combination of heating and venting to reduce humidity and condensation, especially when warm days are followed by cool nights.
azoxystrobin (Quadris): 6.0-15.5 fl oz/A. (0dh, REI 4h, Group 11). Registered for field use.
Bacillus amyloliquefaciens strain D747 (DoubleNickelOG): 0.25 to 3.0 lb/A. (0 dh, REI 4 h, Group 44). Disease suppression only. For improved control; mix or rotate with a chemical fungicide.
cyazofamid (Ranman): 2.75-3.0 fl oz/A. (0 dh, REI 12h, Group 21). Registered for greenhouse use.
mandipropamid (Micora): 8 fl oz/A. (1 dh, REI 4h, Group 40). NOTE: greenhouses use limited to structures with permanent flooring ONLY. Not labeled for field use.
mandipropamid (Revus): 8 fl oz/A. (1 dh, REI 4h, Group 40). Labeled for field use.
potassium bicarbonate (MilStopOG): 2.0 to 3.0 lb/A. (0 dh, REI 1h, Group M1). Uniform and complete coverage is essential for effective results. Do not store unused spray solution. Registered for greenhouse use.
phosphorous acid (Fosphite): 1.0-3.0 qt/100 gal. (0 dh, REI 4h, Group 33). Do not apply to heat or moisture stressed plants or plants recently treated with copper.
Streptomyces lydicus (ActinovateOG): 6 to 12 oz/A. (0 dh, REI 1h , Group NC).
Fusarium Wilt (Fusarium oxysporum f.sp. basilici)
Fusarium wilt is very difficult to manage as it can persist in the soil or hydroponic system for many years. Practice strict sanitation. Begin with disease-free seed or treat seed with hot water or dilute bleach. The basil varieties Nufar and Aroma 2 have resistance to Fusarium wilt. Fusarium is a soil inhabitant that can become established in the field. Promptly remove and destroy all infected plants, infested soil, and plant debris. Rotate crops, excluding members of the mint family, which can be symptomless carriers of Fusarium.