Custard apple is mainly used as a dessert fruit. Developing fruits are often infested by two species of mealy bugs mainly the striped mealy bug and citrus mealy bug. These mealy bugs are small, pink coloured and soft bodied insects covered with white mealy wax. Nymphs and adults fix their mouth at fissures and furrows of rounded fleshy tubercles of the green fruits. When they infest developing fruits and suck the sap the size of the fruit becomes diminished, shrivelled and undergo premature dropping. These mealy bugs also infest at fruit stalks, leaves and terminal shoots causing, yellowing and drying symptoms.
Pest biology
The pest prefers dry weather and heavy incidence often occurs following periods of prolonged drought. They are active and mobile throughout their life. Reproduction is both sexual and through parthenogenesis, the latter being more common. Females lay 100-300 eggs which hatch into nymphs in 3-4 days. The nymph’s period is around 45 days. The longevity of males is 1 to 3 days while that of females extends from 36 to 53 days.
Management methods
To check the infestation of these pests, remove and destroy the affected leaves, fruits and twigs. Apply diazinon or monocrotophos at 0.1 per cent concentration. Spraying of 5 per cent neem seed kernel extract or 3 per cent neem oil suspension is effective. The soil around trees should be ploughed up to a depth of 75 cm followed by mixing of dust formulation of insecticides such as lindane 1.3 per cent or endosulfan 4 per cent at 10 kg/ acre could be done.
A number of parasites are parasitizing the mealy bugs in nature as biological control agents. Release of Cryptoleamus montrouzieri (ladybird beetle) @ 10 Nos./ tree would be quite effective to predate upon the eggs and nymphs of the mealy bugs.
J. JAYARAJ
& M. ANANTHAN
Horticultural Research Station
Thadiyankudisai, Perumparai, Dindigul
Tamil Nadu
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