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 than a lime. Fruits may split due to the activity of the borer. The larvae may then migrate to other fruits. Larvae are covered with a series of red and white rings and have a black collar and head. As they get older, they turn green-bluish. Initially, they feed on pulp, then on the seeds. They cause premature fruit drop, particularly in young fruits. Hundreds of young fruits can be found on the ground under heavily infested trees.
The adult moths show a plain grayish color and have a wingspan of approx. 13 mm. They live for about a week and lay eggs in pairs at the base of fruit peduncles. Larvae enter the fruit and feed on pulp and seeds. Pupation takes place in 1-2 cm deep holes in the bark, which the larvae close with chewed bark particles, rendering them invisible. Adults hatch after 10-14 days and are nocturnal. The pest is distributed through transport of infested fruits and adult moths are capable of flying to different orchards.
You can use neem extract (azadirachtin) formulations against D. albizonalis, applied at weekly intervals, starting when the mango is in flower and continuing for 2 months. Try to maintain natural enemy populations of the mango seed borer, e.g. the wasps Rychium attrisimum (feeding on the larvae) and Trichogramma chilonis and Trichogramma chilotreae which parasitize the eggs of the mango seed borer.
Always consider an integrated approach with preventive measures together with biological treatments if available. Apply sprays containing thiacloprid to effectively treat mango seed borers. Pesticides based on other active ingredients may be effective as well.