NC State Extension Publications

General Information

Information on chemical plant protectants for disease control on greenhouse vegetables must be used in the context of a "Total Disease Control Program." For example, many diseases are controlled by sanitation (no smoking, fumigating soil, using disease-free seed and seedlings, removing all dead plant parts, and washing hands and equipment before moving from one house to another), use of resistant varieties, crop rotation, seed treatment, exclusion of aphids from fall crops, and cultural practices. Always use top-quality seed or plants obtained from reliable sources. Seed are ordinarily treated by the seed producer for the control of seed decay and damping-off. However, tomato seed also should be treated with Clorox to reduce the risk of tobacco mosaic virus and certain bacterial diseases.

Most foliar diseases can be reduced or controlled by maintaining relative humidity under 90%, by keeping the air circulating in the house, and watering in such a manner to avoid wetting leaves.

Spraying with fungicides should be done as to ensure coverage of all plant surfaces. We recommend the use of high-pressure and high-volume equipment or subliming products (Exotherm Termil). Application should start prior to or as soon as the disease first appears and continued on a 7- to 14-day schedule as needed. Before starting the spray schedule, be sure to obtain a diagnosis of the disease in order to use the proper material. This information may be obtained through the local county Cooperative Extension center.

CAUTION: The risk of pesticide exposure in the greenhouse is high; use protective clothing laundered daily or after each exposure; ventilate house during application and use appropriate respirator. Always use the chemical as directed on the label.

Note on Recommendations

Recommendations of specific chemicals are based upon information on the manufacturer's label and performance in a limited number of trials. Because environmental conditions and methods of application by growers may vary widely, performance of the chemical will not always conform to the safety and pest control standards indicated by experimental data. All recommendations for pesticide use were legal at the time of publication, but the status of registration and use patterns are subject to change by actions of state and federal regulatory agencies. 

Chemical Controls

Commodity Disease Active Ingredient (Trade Name) FRAC Rate PHI (days) REI (hours)
Basil Alternaria leaf spot, Botrytis, Fusarium blight cyprodinil + fludioxinil (Switch) 9+12 11 to 14 oz/A 7 12h
Downy mildew cyazofamid (Ranman) 21 2.75 to 3 fl oz/A 0 12h
mandipropamid (Micora, Revus) 40 8.0 fl oz/A 1 4h
Downy mildew, Pythium root rot, Rhizoctonia root rot phosphorous acid (various) 33 See label See label See label
potassium phosphite (various) 33 See label See label See label
Cucurbits Angular leaf spot, Downy mildew copper, fixed (various) M1 See label See label See label
Downy mildew cymoxanil (Curzate) 27 3.2 to 5.0 oz/A 3 12h
Alternaria leaf blight and spot, Gummy stem blight, Powdery mildew cyprodinil + fludioxinil (Switch) 9+12 11 to 14 oz/A 1 12h
Alternaria leaf blight and spot, Anthracnose, Cercospora leaf spot, Gummy stem blight, Powdery mildew, Septoria leaf blight difenoconazole + cyprodinil (Inspire Super) 3+9 16 to 20 fl oz/A 7 12h
Alternaria leaf blight, Anthracnose, Downy mildew, Suppression of Phytophthora blight famoxadone + cymoxanil (Tanos) 11+27 8 (to 10) oz/A 3 12h
Botrytis gray mold fenhexamid (Decree) 17 1.5 lb/A or 1 to 1.5 lb/A if tank mixed 0 12h
Alternaria leaf spot, Anthracnose, Cercospora leaf spot, Downy mildew, Gummy stem blight, Scab mancozeb (various) M3 See label See label See label
Alternaria leaf spot, Cercospora leaf spot, Downy mildew, Phytophthora rot mancozeb + zoxamide (Gavel) M3+22 1.4 to 2 lb/A 5 48h
Suppression of Downy mildew, Suppression of Phytophthora blight mandipropamid (Revus) 40 8 fl oz/A 0 4h
Alternaria leaf spot, Botrytis, Gummy stem blight, Powdery mildew, Sclerotinia stem rot penthiopyrad (Fontelis) 7 0.375 to 0.5 fl oz/gal to treat 1,360 sq ft 1 12h
Botrytis gray mold, Corynespora leaf spot, Early blight, Gummy stem blight, Powdery mildew, Scab polyoxin D zinc salt (Affirm, OSO) 19

See label

0 4h
Powdery mildew potassium bicarbonate (Milstop) NC 1.25 to 5.0 lb/100 gal 0 1h
cyflufenamid (Torino) U6 3.4 oz/A 0 4h
sulfur (various) M2 See label See label See label
triflumizole (Procure, Terraguard) 3 See label 1 12h
Alternaria leaf spot, Anthracnose, Cercospora leaf spot, Downy mildew, Gummy stem blight, Scab, Target spot potassium phosphite + chlorothalonil (Catamaran) 33+M5 4 pt/A or 6 pt/A depending on disease 1 12h
Damping off and root rots (Phytophthora spp. and Pythium spp.) propamocarb hydrochloride (Previcur Flex) 28 See label 2 12h
Lettuce Downy mildew cymoxanil (Curzate) 27 See label See label

12h

Alternaria leaf spot, Botrytis gray mold, Sclerotinia rot, Basal rot, Septoria leaf spot, Suppression of Powdery mildew cyprodinil + fludioxinil (Switch) 9+12 11 to 14 fl oz/A 0 12h
Botrytis gray mold, Drop rot, Sclerotinia minor, Watery soft rot dicloran (Botran) 14 See label 14 12h
Downy mildew, White rust famoxadone + cymoxanil (Tanos) 11+27 8 to 10 oz/A 1 12h
Botrytis gray mold fenhexamid (Decree) 17 See label 3 12h
Anthracnose, Downy mildew manxozeb (various) M3 See label See label See label
Downy mildew mandipropamid (Micora, Revus) 40 See label See label 4h
Alternaria leaf spot, Botrytis gray mold, Cercospora leaf spot, Powdery mildew, Septoria leaf spot penthiopyrad (Fontelis) 7 14 to 24 fl oz/A 3 12h
Alternaria leaf spot, Anthracnose, Botrytis, Cercospora leaf spot, Powdery mildew potassium bicarbonate (Milstop) NC 1.25 to 5.0 lb/A 0 1h
Damping off root rots (Phytophthora and Pythium spp.) propamocarb hydrochloride (Previcur Flex) 28 See label 2 12h
Powdery mildew sulfur (various) M2 See label See label See label
Alternaria leaf spot/black spot, Powdery mildew triflumizole (Procure) 3 6 to 8 fl oz/A 0 12h
Tomato (after transplanting in a greenhouse) Anthracnose, Black mold, Early blight, Gray leaf spot, Powdery mildew, Septoria leaf spot, Target spot azoxystrobin + difenoconazole (Quadris Top) 11+9 8 fl oz/A 0 12h
Anthracnose, Bacterial speck and spot, Early blight, Gray leaf mold, Late blight, Septoria leaf spot copper, fixed (various) M1 See label See label See label
Late blight, Phytophthora blight cyazofamid (Ranman) 21 See label 0 12h
Late blight cymoxanil (Curzate) 27 3.2 to 5.0 oz/A 3 12h
mefenoxam + mancozeb (Ridomil Gold) 4+M3 2.5 lb/A 5 48h
Early blight, Botrytis gray mold, Powdery mildew cyprodinil + fludioxinil (Switch) 9+12 11 to 14 oz/A 3 12h
Anthracnose, Black mold, Botrytis gray mold, Early blight, Gray leaf spot, Leaf mold, Powdery mildew, Septoria leaf spot, Target spot difenoconazole + cyprodinil (Inspire Super) 3+9 16 to 20 fl oz/A 0 12h
Phytophthora and Pythium root rots etridiazole (Terramaster) 14 6 to 7 fl oz/A 3 12h
fosetyl-Al (various) 33 2.5 to 5 lb/A 14 12h
Anthracnose, Early blight, Late blight, Leaf mold, Septoria leaf spot, Suppression of: Bacterial canker, spot, and speck; Buckeye rot famoxadone + cymoxanil (Tanos) 11+27 See label 3 12h
Botrytis gray mold fenhexamid (Decree) 17 See label 0 12h
Anthracnose, Bacterial speck and spot, Early blight, Gray leaf spot, Late blight, Leaf mold, Septoria leaf spot mancozeb (various) M3 See label See label See label
mancozeb + copper (ManKocide) M1+M3 See label 5 48h
mancozeb + zoxamide (Gavel) M3+22 1.5 to 2 lb/A 5 48h
Anthracnose, Black mold, Early blight, Gray leaf spot, Late blight, Leaf mold, Powdery mildew, Septoria leaf spot, Target spot mandipropamid + difenoconazole (Revus Top) 3+40 5.5 to 7 fl oz/A 1 12h
Powdery mildew, Southern blight myclobutanil (Rally) 3 2.5 to 4 oz/A 0 48h
Anthracnose, Black mold, Botrytis gray mold, Early blight, Gray leaf spot, Leaf mold, Basal stem rot, Powdery mildew, Septoria leaf spot, Target spot, Suppression of Anthracnose penthiopyrad (Fontelis) 7 0.5 to 0.75 fl oz/gal per 1,360 sq ft 0 12h
Phytophthora root rot phosphorous acid (various) 33 See label See label See label
Botrytis rot, Early blight, Powdery mildew, Suppression of Anthracnose polyoxin D zinc salt (Affirm, OSO) 19 See label 0 4h
Early blight, Gray leaf mold, Gray leaf spot, Late blight, Septoria leaf spot, Target spot potassium phosphite + chlorothalonil (Catamaran) 33+M5 See label 0 12h
Damping off and root rots (Pythium and Phytophthora spp.) propamocarb hydrochloride (Previcur Flex) 28 See label 5 12h
Botrytis gray mold pyraclostrobin + boscalid (Pageant Intrinsic) 7+11 23 oz/A 0

12h

Botrytis gray mold, Early blight pyrimethanil (Scala) 9 7 fl oz/A 1 12h
Powdery mildew sulfur (various) M2 See label See label See label
triflumizole (Terraguard) 3 2 to 4 fl oz/100 gal 1 12h
Anthracnose, Early blight, Septoria leaf spot zinc dimethyl-dithio-carbamate (Ziram) M3 3 to 4 lb/A 7 48h

Note: This information was adapted from the Southeastern Vegetable Handbook in 2017.

Acknowledgements

Charles Averre, S. F. Jenkins, Paul B. Shoemaker

Authors:

Extension Associate, Vegetable and Herbaceous Ornamental Pathology
Entomology and Plant Pathology
Research Assistant
Entomology and Plant Pathology

Publication date: Dec. 6, 2017

The use of brand names in this publication does not imply endorsement by the North Carolina Cooperative Extension Service of the products or services named nor discrimination against similar products or services not mentioned.

Recommendations for the use of agricultural chemicals are included in this publication as a convenience to the reader. The use of brand names and any mention or listing of commercial products or services in this publication does not imply endorsement by North Carolina Cooperative Extension nor discrimination against similar products or services not mentioned. Individuals who use agricultural chemicals are responsible for ensuring that the intended use complies with current regulations and conforms to the product label. Be sure to obtain current information about usage regulations and examine a current product label before applying any chemical. For assistance, contact your county Cooperative Extension agent.

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