Mango Fruit Borer
Pea- or lime-sized fruits display black entry holes, often surrounded by a round discolored patch at the distal end of the hanging fruit. Chewed pulp and sap material exudes from the entry hole when the fruits are larger. Fruits may split due to the extensive tunneling of the borer. The larvae might migrate to other fruits then. Newly hatched larvae are pale pink with a dark brown to black head. Later, they turn reddish-brown. Initially, they scrape the fruit skin, causing scab-like patches, then they bore into the fruit, which may cause premature dropping of young fruits. Hundreds of them can be found under heavily infested trees. The infested fruits drop prematurely.
The adult moth has dark brown forewings and pale white-gray hindwings. The adult is a medium-sized moth with a wingspan of 20 mm. Adult moths live for about a week and lay 125-450 eggs on rough areas of the fruit and pedicels. Larvae enter the fruit and feed on the pulp and seed. A fully grown caterpillar measures about 20 mm in length. It pupates in a loosely woven silken cocoon in the soil adjacent to the fallen fruit. Development takes about 30 days. The pest is distributed through transport of infested fruits. What is more, adult moths are capable of flying to different orchards.
Apply neem extracts (azadirachtin) at weekly intervals, starting when the mango is in flower and continue for 2 months. Try to maintain natural enemy populations of the mango fruit borer, e.g. the wasps Rychium attrisimum (feeding on the larvae) and Trichogramma chilonis and Trichogramma chilotreae which parasitize the eggs.
Always consider an integrated approach with preventive measures together with biological treatments if available. Sprays containing thiacloprid will effectively control mango fruit borers. Also, pesticides based on fenpropathrin and fenthion (0.1%) sprayed on marble-sized fruits showed satisfying results. Sprays containing chloripyriphos (2.5 ml/l)or dichlorovas (1.5 ml/l) or carbaryl (3 g/l water) also decimate mango fruit borers effectively.