By Charei Munene
The banana weevil is the most important pest of bananas. The banana weevil is among the principal limiting factors of banana production in East Africa. This pest is mainly spread through infested plant material which has eggs and worm like stages of the weevils. Adult banana weevils are initially reddish-brown before eventually turning black with a hard shell. They hide during the day and rarely fly. Their damage is done by the tunneling at the base of the banana. This weakens the plant and the banana easily falls when blown by the wind. The adult can live for long periods without food and has been recorded to live for over two years. The complete life cycle is from 30 to 40 days. Eggs are laid in the base of the banana, which then hatch approximately eight days later. Upon hatching the worm like stage burrows into the below ground part of the banana creating tunnels and causing damage to the banana stem.
Symptoms
- Reduced plant growth
- Yellowing of the leaves
- Weak or dying suckers
- Weakened plants which fall easily under windy conditions
- Smaller bunch size and small fruits
- Shortened plantation life
Prevention
- Use of clean certified planting material especially tissue culture bananas.
- Plant banana varieties that are resistant to banana weevils.
- Remove all underground remains of the old banana crop after harvesting.
- If possible, leave land that you had planted bananas fallow for at least six months.
- Eliminate weeds from the fields.
- Use spotless and solid suckers for establishing a new plantation.
- Uncover the inner soil layers for exposure to the sun before planting.
- Cut old stems into stripes for mulching.
- Do sufficient manuring, strong bananas can withstand weevil attack for some time.
Control
- Ensure good hygiene to reduce breeding sites for the weevils.
- Traps can be made by placing sliced sections of the below ground part of banana or sections of the stems on the ground. Place the traps at the base of the bananas. Weevils will be attracted to them. Adults trapped should be destroyed.
- Set up pheromone traps to trap adult weevils.
- Regularly monitor banana weevil activity by placing baits and assessing for damage.
- Dip your suckers in neem solution or hot water (55%C) for 25 minutes before planting to kill weevil eggs.
- Cut old stems at ground level and cover with soil to prevent egg laying.
Charei Munene is the Infonet Knowledge Manager at Biovision Africa Trust
Email: cmunene@biovisionafrica.org