Disease Control : New England Vegetable Management Guide : UMass Amherst

Basil - General Basil Insect Control Basil Weed Control

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.

FRAC Group BM02:

Bacillus amyloliquefaciens F727 (Stargus^OG): 0.5 to 4 qt/A; PHI 0d, REI 4h. Apply preventatively.

FRAC Group NC:

potassium bicarbonate (PB 133, MilStop SP^OG): 2 to 5 lb/100.0 gal; PHI 0d, REI 1h. See label for small volume application rates.

FRAC Group 9:

cyprodinil + fludioxonil (Switch 62.5 WG): 11 to 14 oz/A; PHI 7d, REI 12h, Groups 9 & 12. Do not make more than 2 consecutive applications.

FRAC Group 12:

cyprodinil + fludioxonil (Switch 62.5 WG): 11 to 14 oz/A; PHI 7d, REI 12h, Groups 9 & 12. Do not make more than 2 consecutive applications.

Damping-off and Crown and Root Rots (Pythium spp., Rhizoctonia spp., Fusarium spp. & Phytophthora spp.)

Use pasteurized soil or soilless 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.

FRAC Group BM02:

Bacillus amyloliquefaciens F727 (Stargus ^OG): 1 to 4 qt/A; PHI 0d, REI 4h. Apply preventatively with a minimum of 50 gallons of water/A.

FRAC Group 4:

mefenoxam (Ridomil Gold SL): 0.5 to 1 pt/A; PHI 21d, REI 48h. Pythium only.

FRAC Group 12:

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

FRAC Group P07:

potassium phosphite (K-Phite 7LP): 1 to 4 qt/A; PHI 0d, REI 4h. Apply in a minimum of 20 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 increasing 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).

FRAC Group BM01:

thyme oil (Guarda): 1 gal/29–159 gal water (0.625%–3.3% v/v); PHI 0d, REI 0h.

Group BM02:

Bacillus amyloliquefaciens F727 (Stargus ^OG): 1 to 4 qt/A; PHI 0d, REI 4h. Apply preventatively.
Streptomyces lydicus WYEC 108 (Actinovate ^OG): 3 to 12 oz/A; PHI 0d, REI 4h.

FRAC Group M01:

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

FRAC Group NC:

hydrogen peroxide and peroxyacetic acid (Oxidate 2.0^OG): 1:100 dilution (curative) or 1:200 to 1:400 dilution (preventative); PHI 0d, REI until sprays dry (field), 1h fogging/spraying or 0h other methods (enclosed areas). Do not tank mix with copper.
potassium bicarbonate (PB 133, aka MilStop SP^OG): 1.25 to 5 lb/100 gal; PHI 0d, REI 1h. Thorough coverage is essential. See label for small volume application rates.

FRAC Group P04:

laminarin (Vacciplant): 14 to 22 fl oz/A; PHI 0d, REI 4h.

FRAC Group P07:

potassium salts of phosphorous acid (Fosphite): 1 to 3 qt/minimum 20 gal/A; PHI 0d, REI 4h. Do not apply to plants that are heat- or moisture-stressed.

FRAC Group 4:

mefenoxam (Subdue Maxx): 2 pt/A; PHI 21d, REI 48h. Tank-mix with fungicides from other groups.

FRAC Group 11:

azoxystrobin (Heritage): 0.18 oz/A; PHI 0d, REI 4h.
fenamidone (Reason 500 SC): 6 fl. oz/A; PHI 2d, REI 12h. Rotate with non-Group 11 fungicides.

FRAC Group 21:

cyazofamid (Ranman 400SC): 2.75 to 3 fl oz/A; PHI 0d, REI 12h.

FRAC Group 40:

mandipropamid (Micora): 8 fl oz/A; PHI 1d, REI 4h. Greenhouses use limited to structures with permanent flooring only. Not labeled for field use.
mandipropamid (Revus): 5.5 to 8 fl oz/A; PHI 1d, REI 4h. Field use only.

FRAC Group 43:

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

FRAC Group 49:

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

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.