The banana weevil is a small black insect with a long, curved snout. Attacked banana and plantain plants grow slowly and produce small fruits. The weevils make holes in the underground part and in the lower part of the banana stem. The weevils make the leaf sheaths split. When you cut the stem open, you will see tunnels made by the small, white grubs which are the young of the weevils. The tunnels weaken the plant, and it may fall over.
How weevils live
Banana weevils live in the trash around the banana plant. Weevils like hiding in the dried banana fibres at the bottom of the stem. Female weevils lay their eggs in the base of the stem, just above ground level, or in cut stems left after harvesting. The weevil eggs hatch into grubs that feed on the plant. The weevils are spread to a new garden through infested suckers.
How to control banana weevils
1. Use clean suckers to avoid spreading weevils. Clean the suckers by trimming them with a knife to remove the old roots where the weevils may hide. Continue to keep weevils out of your garden by removing all the dried banana fibres and any infested plants. Chop up the infested plants and feed them to your animals.
2. After harvesting the fruit, chop the stem into many small pieces and spread them around so that they dry quickly before weevils can lay eggs in them. Keep the soil bare for two feet, or 60 centimetres around the stool, so that the weevils do not lay their eggs in the banana plant.
3. Fertilise the soil by adding manure every season. Mulch your plants, but keep mulch and manure 60 centimetres from the banana plant, so they do not attract weevils.
4. Set traps for weevils remaining in the garden. Cover the stump with the split stem. This will attract weevils from within the stump and from other parts of the garden. Regularly check the trap for weevils and kill them.