Durian fruit borer
Caterpillars bore into young and growing fruits through the stalk, base or side, leaving holes with frass, and fruits rot or drop.
Crops it attacks
Where the damage shows
When to act
From 2 weeks after fruit set, check every fruit cluster each week, mostly where fruits touch and at the stalk, for small holes with wet brown frass. Act at the first fresh holes: remove bored fruits and treat or wrap the rest.
What to spray
Active ingredients only, never brands. The IRAC group tells how it works: switch to a different group next time, so the pest does not learn to survive it. Spray only when the damage is worth the cost, and only with products registered with the Fertilizer and Pesticide Authority for your crop. Follow the label. The Shopee and Lazada links only show who sells something with that active ingredient, not a recommendation of any seller or product.
How to prevent it
- Thin fruit clusters so fruits do not touch, or slip a piece of sack or foam between them. Borers enter where fruits press together.
- Pick off and bury bored and fallen fruits every week, so the caterpillars cannot pupate.
- Wrap young fruits in net bags where labor allows.
- Prune the canopy open so fruits are easy to reach, check and treat.
- Clear wild hosts of the shoot and fruit borer near the orchard, such as castor and unpicked fruits.
Natural enemies and biological help
- Egg wasps, ants and spiders attack eggs and young caterpillars on the fruit. Avoid broad sprays.
- Bt sprays on young fruits kill small caterpillars before they bore in.
Not sure it is this one?
Many pests look alike. Send a photo to Anee, the smart farm technician in anee.io. She reads it with your crop, its age and the weather, and tells you what it most likely is and what to do first. In Tagalog or English.