Sapota, a native of Mexico, is grown widely in India for its fruit and milky latex which is the source of chicle used to make chewing gum.
Of the several pests infesting the tree, the sapota leaf webber (Nephopteryx eugraphella) commonly called as chickoo moth is a major one.
As the name indicates, the caterpillars of the moth spin web on the leaves and also feed on tender leaves and fruits throughout the year.
Presence of dry leaf clusters and dark brown patches on the leaves are clear symptoms of the infestation and can be easily spotted from a long distance.
The infestation leads to withering and drying of tree branches. The pest activity increases with appearance of new shoots and buds. A wide range of sapota varieties are susceptible to this pest.
The moth is grey in colour measuring around one centimetre in length. It lays eggs on leaves and buds of young shoots. Around 350 eggs are laid by a single female. The incubation period is around one week and after hatching the pink coloured caterpillars start feeding on green leaves by scrapping the chlorophyll content leaving behind a fine network of veins.
They also bore inside the flower buds and tender fruits which wither away and drop down.
The larvae can damage many fruit buds during its developmental period which lasts from 13 to 60 days according to environmental conditions. Pupal stage is completed in 8 to 29 days. There are eight to nine generations of this pest in a year.
— Remove and destroy all the webbed leaves, shoots, buds and fruits along with larvae.
— Crowded and crossing branches should be pruned.
— Plant resistant varieties such as PKM 1 Sapota
— Erect light trap at one per hectare to monitor the activity of chickoo moth
— Spray two rounds of carbaryl 0.1 per cent, chlorpyriphos 0.05 per cent or quinalphos 0.05 per cent at 20 days interval after new shoot formation and fruit harvest.
(J.Jayaraj, Associate Professor and R.K. Murali Baskaran, Head, Department of Entomology ,Agricultural College and Research Institute, TNAU, Madurai - 625 104. phone: 0452- 2422956 Extn: 214)