Papaya Leaf Curl
The most obvious symptoms of this disease are the downward or inward curling leaves. Other symptoms include the thickening of the leaf veins, sometimes with the formation of outgrowths. Leaves become leathery and brittle and petioles have a deformed, often twisted aspect. Top leaves are most affected. At later stages of the disease defoliation can occur. Plant growth is stunted and the production of flowers or fruits may be compromised. If present at all, fruits are small, distorted in shape and tend to fall prematurely.
The main vector for the transmission of the virus is the whitefly Bemisia tabaci. It spreads the virus from plant to plant in a non-persistent manner. This means that the transmission takes place within the few seconds while the virus is still active in the vector. Other ways in that the disease is spread is via infected seedlings or seeds as well as through grafting material. Papaya leaf curl virus is not transmitted through mechanical work in the field. Alternative hosts are tomato and tobacco plants. The virus is widely distributed but as of today it has a limited incidence. However, in some specific cases, it can result in severe economic losses.
Spray white oil emulsions (1%) to hinder the uptake and transmission of the virus by aphids.
Always consider an integrated approach with preventive measures and biological treatments if available. There is no chemical treatment for viral infections. However, holding the population of whiteflies in check can reduce the severity of the infection. Soil application of carbofuran at the time of sowing and 4-5 foliar sprays of dimethoate or metasystox at an interval of 10 days can effectively control whitefly populations.