Diseases of Fruit Plantation Medicinal and Aromatic Crops

Rose and Tuberose Grey blight / grey rot

Causal organism: Botrytis cineria and Boytritis elliptica
Symptoms

• Infection starts from the sepals as black-brown specks the flower in due course .
• The buds turn brown and decay.
• Sometimes partially opened buds are attacked and individual petals turn brown and shrivel.
• In susceptible hybrid tea roses the disease prevents anthesis.
• In cool moist weather the flower is covered with grayish- grey or darkish growth of the fungus.
• Affected flowers mummification takes place and harbor the disease
• Winter killed canes harbour infection.
Etiology

• Conidiophores arise in clusters, brown to dark brown, long, septate, slender, repeatedly branched and thick walled .
• Conidia are ovoid to oblong. Disc- shaped .
Management

• picking and destroying old blooms and overwintered canes help in reducing the disease.
• Avoiding excess irrigation helps to check the disease.
• Fungicidal spray with triphenyl tin acetate(Brestan) 0.05 per cent is effective in its control.
• The disease is effectively controlled by spraying with ferbam 0.2% or capton 0.2% or benomyl 0.1 per cent or mancozeb 0.25%
• The following rose varities viz., Anieval sparks, Bonnienuit, chantare, cahrleston etc. are free from disease.