See:
Greenhouse Plants, Ornamental - Gray Mold
Cause Botrytis cinerea, a fungus that colonizes dead, dying, and wounded plant parts. From these infections it can attack healthy tissues. A moist, humid environment is ideal for pathogen sporulation and spread. Conidia may come from sources in and outside the greenhouse. It is found everywhere plants are grown and has a wide host range. Flower petals are most susceptible at any stage of development.
Symptoms Flower parts develop water-soaked lesions that become necrotic and die. A gray mass of spores develops on necrotic tissue during wet conditions. Entire petals or flowers may become diseased. Senescent leaves may also be attacked.
Cultural control
- Remove all dead and dying plant parts (particularly blossoms) on and around plants.
- Avoid overhead irrigation or apply such that plants are not wet for extended periods of time.
- Space plants for good air circulation.
Chemical control Best used with cultural controls. Tank-mix and/or alternate products with different modes of action to prevent the buildup of resistant fungi. Limit the use of any one group during crop production.
- Astun at 10 to 17 fl oz/100 gal water. Group 7 fungicide. 12-hr reentry.
- Broadform at 4 to 8 fl oz/100 gal water. Group 7 + 11 fungicide. 12-hr reentry.
- Chipco 26019 FLO at 1 to 2.5 quarts/100 gal water. Group 2 fungicide. 12-hr reentry.
- Decree 50 WDG at 0.75 to 1.5 lb/100 gal water. Group 17 fungicide. 12-hr reentry.
- Fore 80 WP at 1.5 lb/100 gal water. Do not use on French dwarf-double or signet-type marigold seedlings. 24-hr reentry.
- Medallion WDG at 2 to 4 oz/100 gal water. Using with oils or adjuvants may damage plant. Group 12 fungicide. 12-hr reentry.
- OHP 6672 4.5 F at 10 to 14.5 fl oz/100 gal water plus another fungicide. 12-hr reentry.
- Orkestra at 8 fl oz/100 gal water. Group 7 + 11 fungicide. 12-hr reentry.
- Pageant at 12 to 18 oz/100 gal water. Do not use with organosilicone-based adjuvants. Group 7 + 11 fungicide. 12-hr reentry.
- Palladium at 4 to 6 oz/100 gal water. Avoid excessive runoff to small plants, which may result in stunting and/or chlorosis. Group 9 + 12 fungicide. 12-hr reentry.
- Phyton 27 at 1.3 to 2 oz/10 gal water. Group M1 fungicide. 48-hr reentry.
- Postiva at 10 to 28 fl oz/100 gal water. Group 3 + 7 fungicide. 12-hr reentry.
- Spirato GHN at 2 to 4 fl oz/100 gal water. Use with oils or adjuvants may cause plant damage. Group 12 fungicide. 12-hr reentry.
- Switch WG at 11 to 14 oz/A. Do not use within 7 days of harvest. Group 9 + 12 fungicide. 12-hr reentry.
- Terraguard SC at 4 to 8 fl oz/100 gal water. Group 3 fungicide. 12-hr reentry.
Biological control
- Prestop (Gliocladium catenulatum strain J1446) at 0.33 oz/5 gal water. Do not use with other products in the tank. 4-hr reentry. O
Reference Pande, S., Stevenson, P., Narayana Rao, J., Neupane, R.K., Chaudhary, R.N., Grzywacz, D., Bourai, V.A., and Krishna Kishore, G. 2005. Reviving chickpea production in Nepal through integrated crop management, with emphasis on Botrytis gray mold. Plant Disease 89:1252-1262.