Fruit flies
Flies that lay eggs inside ripening fruit; the maggots rot the fruit from within.
Also known as: Oriental fruit fly, Melon fly, Bactrocera
Symptoms and identification
Small puncture marks on the fruit skin, sometimes oozing sap, followed by soft, brown, rotting patches. Fruit drops early and contains white maggots when cut open. Guava, mango and gourds are especially affected.
Causes
Female flies are attracted to ripening fruit, especially in warm, humid weather. Fallen, infested fruit left on the ground lets the next generation develop in the soil.
Organic treatment
Hang pheromone (methyl eugenol or cue-lure) traps, 4–5 per large garden. Use homemade bait traps of fruit juice with a little jaggery. Turn the soil under trees to expose pupae.
Prevention
Collect and destroy fallen fruit every day. Bag young fruit in paper bags, and pick fruit as soon as it starts to colour.
Chemical treatment (use with care)
Bait sprays with protein hydrolysate and an approved insecticide can be applied to foliage (not fruit) following local guidance.