Diseases of Fruit Plantation Medicinal and Aromatic Crops

Leaf curl of papaya

Causal organism: Tobacco leaf curl virus

• The disease effects yield and quality of fruits and serious losses are caused in terms of production and productivity.
Symptoms

• The disease is transmitted by the vector white fly (Bemisia tabaci).
• Severe curling, crinkling and deformation of leaves characterize the disease and mostly the young leaves are affected.
• Apart from curling, leaves also exhibit vein clearing and thickening of the veins.
• Sometimes the petioles are twisted. In severe cases complete defoliation of the infected plant is observed.
• The infected plants show stunted growth with reduced fruit yield.
Causal virus
• The disease is caused by Tobacco leaf curl virus, belonging to Gemini virus group.
• It is not seed or soil borne nor sap transmissible but is transmitted by grafting and white flies.
• The germinated particle contain ssDNA.
Epidemiology

• The virus causing leaf curl disease of papaya has wide host range like Zinnia elegance, tomato, tobacco, and datura. White fly is the major vector transmitting the disease.
Management

• Removal and destruction inffected plants is the only control measure to reduce the spread of the disease.
• Checking white fly population can also reduce the infection severity.
• Soil application of Carbofuran (1 kg a.i./ha) at the time of sowing and 4-5 foliar sprays of Dimethoate (0.05%) or Metasystox (0.02%) or Nuvacron (0.05%) at an interval of 10 days effectively controls the whitefly population.