Disease Control

NOTES: 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 26 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.

Bacillus amyloliquefaciens F727 (StargusOG): 2.0 to 4.0 qt/A; PHI 0d, REI 4h, Group BM02. Apply preventatively in a minimum of 50.0 gallons of water/A.

cyprodinil plus fludioxonil (Switch 62.5 WG): 11.0 to 14.0 oz/A; PHI 7d, REI 12h, Groups 9 & 12. Do not make more than 2 consecutive applications.

potassium bicarbonate (PB 133, MilStop SPOG): 2.5 to 5.0 lb/100.0 gal; PHI 0d, REI 1h, Group NC. See label for small volume application rates.

Ulocladium oudemansii U3 strain (BotryStopOG): 2.0 to 4.0 lbs/A; REI 4h, Group NC. 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 shore flies. 

Bacillus amyloliquefaciens F727 (StargusOG): 2.0 to 4.0 qt/A; PHI 0d, REI 4h, Group BM02. Apply preventatively in a minimum of 50.0 gallons of water/A.

mefenoxam (Ridomil Gold SL): 0.5 to 1.0 pt/A; PHI 21d, REI 48h, Group 4. Pythium and Phytophthora ONLY.

fludioxonil (Maxim 4FS): 0.08 to 0.16 oz/100 lb seed; REI 12h, Group 12. For protection against seedborne and soil-borne fungi. Does not control Pythium or Phytophthora.

potassium phosphite (K-Phite 7LP): 1.0 to 4.0 qt/A; PHI 0d, REI 4h, Group P07. Apply in a minimum of 20.0 gal water/A.

Downy Mildew (Peronospora belbarhii)

Downy mildew of basil can be serious in both field and greenhouse production. Start with certified, disease-free seed. Scout crops regularly and promptly remove and destroy infected plants. Reduce leaf wetness duration 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. Varieties with some resistance to downy mildew are available (see varieties).

azoxystrobin (Heritage): 0.18 oz/A; PHI 0d, REI 4h, Group 11. See label for instructions.

Bacillus amyloliquefaciens F727 (StargusOG): 2 to 4 qt/A; PHI 0d, REI 4h, Group BM02. Apply preventatively in a minimum of 50.0 gallons of water/A.

copper octanoate (Cueva): 16.8 gal/A; PHI 0d, REI 4h, Group M01. Begin applications when environmental conditions favor disease development. 

cyazofamid (Ranman 400SC): 2.75 to 3.0 fl oz/A; PHI 0d, REI 12h, Group 21. Registered for greenhouse use.

fenamidone (Reason 500 SC): 6.0 fl. oz/A; PHI 2d, REI 12h Group 11. Greenhouse and field. Do not alternate with other Group 11 fungicides.

fluopicolide (Presidio 4SC): 4.0 fl oz/A; PHI 1d, REI 12h, Group 43. Field use only. Must be tank mixed with a fungicide with a different mode of action. 

hydrogen peroxide and peroxyacetic acid (Oxidate 2.0OG): 1:2 to 1:4 dilution; PHI 0d, REI 0h. Do not tank mix with copper. 

laminarim (Vacciplant): 14.0 to 22.0 fl oz/A; PHI od, REI 4h, Group P04. See label for application methods and restrictions. 

mandipropamid (Micora): 8.0 fl oz/A; PHI 1d, REI 4h, Group 40. NOTE: greenhouses use limited to structures with permanent flooring ONLY. Not labeled for field use.

mandipropamid (Revus): 8.0 fl oz/A; PHI 1d, REI 4h, Group 40. Labeled for field use.

mefenoxam (Subdue Maxx): 2.0 pt/A; PHI 21d, REI 48h, Group 4. Tank mix with fungicides from other groups. 

oxathiapiprolin (Segovis): 1.1 to 2.4 fl.oz/A; PHI 0d, REI 4h, Group 49. Begin foliar application prior to disease development. Use the higher rate when disease is present. 

potassium bicarbonate (PB 133 AKA MilStop SPOG): 2.5 lb/100 gal; PHI 0d, REI 1h, Group NC. Thorough coverage is essential. Registered for greenhouse and field use. See label for small volume application rates.

potassium salts of phosphorous acid (Fosphite): 1.0 to 3.0 qt/100.0 gal/A; PHI 0d, REI 4h, Group P07. Do not apply to plants that are heat or moisture stressed.

Streptomyces lydicus (ActinovateOG): 6.0 to 12.0 oz/A; PHI 0d, REI 1h, Group NC.

thyme oil (Guarda): See label for rate; PHI 0h, REI 0h, Group NC. See label for application methods and rates. Ensure thorough coverage to the point of runoff ( 15-25 gallons per acre.)

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 Aroma 2, Nufar, Newton and Rutgers Obsession have some 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.