Botrytis (Gray mold, Botrytis cinerea)
Type: Fungal plant pathogen
Taxonomy:
- Kingdom: Fungi
- Phylum: Ascomycota
- Class: Leotiomycetes
- Order: Helotiales
- Family: Sclerotiniaceae
- Genus: Botrytis
- Species: Botrytis cinerea
Description:
Botrytis cinerea is a necrotrophic fungus that attacks a wide range of herbaceous plants, ornamentals, and fruit crops. It produces grayish-brown, velvety mycelium and conidia (spores) on infected plant tissue, which gives the characteristic “gray mold” appearance. Infection typically occurs on senescing, wounded, or stressed tissue but can also affect healthy tissues under high humidity.
Symptoms on Plants:
- Soft, water-soaked lesions on leaves, stems, flowers, and fruit.
- Gray fuzzy mold on decaying tissue, often with brown spots on leaves.
- Blossom and fruit rot, particularly in grapes, strawberries, tomatoes, and ornamental flowers.
- Infected seeds or bulbs may fail to germinate or produce stunted seedlings.
Life Cycle & Ecology:
- Overwinters as sclerotia or mycelium in plant debris.
- Conidia are dispersed by wind, rain, and insects.
- Thrives in cool, moist, and humid environments, often spreading rapidly under greenhouse conditions.
Control & Management:
- Cultural practices: Remove infected plant debris, ensure good air circulation, avoid overhead irrigation, and prune to reduce humidity.
- Chemical control: Fungicidal sprays such as copper-based products, synthetic fungicides, or biological control agents.
- Resistant varieties: Grow cultivars less susceptible to gray mold when available.
- Sanitation: Clean tools and surfaces to prevent spread between plants.
Botanical Significance:
Botrytis cinerea is one of the most economically important fungal pathogens in horticulture and viticulture. It causes post-harvest losses in fruits and vegetables and can significantly reduce ornamental plant quality. Some strains are used intentionally in winemaking (“noble rot”) to produce sweet dessert wines, but most infections are harmful.