I think it is fruit fly damage. The female fruit flies pierce the fruit to lay egg under skin. Generally they lay 3 to 8 eggs. After one or two days the hatched maggots starts feeding on internal content of fruits causing sunken, discoloured patches, distortions and open cracks. This damage also act as entry site for fungal and bacterial pathogens which causes fruit rot. After few days the maggots fall out of the fruit and pupate in soil.
1. Destroy the infected fruits.
2. Also harvest fruits early to reduce flies damage .
3. Use traps to monitor fruit flies. Traps can be purchased in the market or one can prepare themselves. Take plastic container with lids (one quarts yogurt container is fine). Drill holes (10 to 16 holes) that are 3/16-inch in diameter around the upper side of the container. Add 1 to 2 inch of vinegar and 4 -5 drops of unscented liquid dishwashing soap into the container. Place the container in shade near plants before fruits ripening and check the traps frequently for flies. Change the vinegar every week.
4. Spraying protein bait under leaf surface attract flies to single spot which make easier to kill them.
5. Also spray neem oil frequently to repel fruit flies.
5. If infestation is severe you can spray suitable insecticide.
Fruit fly maggots in watermelon fruit. They are about 1cm long © A. M. Varela, icipe
Adult mediterrenean fruit fly Ceratitis capitata
Fruit fly trap
© A.M. Varela and A.A. Seif, icipe
Posted by: Dr. Ravishankar Narayana
Posted: June 24, 2016