Banana rhizome (corm) weevil
Its grubs tunnel the corm at the plant’s base — poor growth, small bunches, toppling plants, and spread on infested suckers.
- Pest type
- Corm-boring weevil
- Attacks
- Corm / rhizome (base)
- Worst in
- Infested suckers; old plantations
- Main risk
- Destroyed corm; toppling; small bunches
Overview
The banana rhizome weevil (banana corm weevil) is a shiny black weevil whose grubs attack the corm — the underground rhizome at the base of the banana plant. The adults are nocturnal and hide at the base of the plant; the female lays eggs in the corm and leaf-sheath bases, and the grubs bore into the corm, tunnelling it and destroying the tissue from which roots and the shoot arise.
This root-and-base damage means attacked plants grow slowly, throw up weak suckers, produce small bunches, and topple easily because their anchorage is gone. The weevil moves mainly on infested suckers, so it is very often introduced with the planting material — which makes using clean, pest-free suckers (or paring/treating them) the single most important control, alongside base hygiene and trapping the adults.
How to identify it
- Poor, slow growth and weak suckers, with small bunches — the above-ground signs of a damaged corm.
- Plants that topple easily because the tunnelled corm no longer anchors them.
- On cutting the corm, dark tunnels and galleries bored through it, with white grubs inside.
- Shiny black weevils hiding at the base of the plant and among the leaf-sheath bases, active at night.
The damage it does
- Tunnelled, destroyed corm tissue that cripples root and shoot development.
- Poor growth, weak suckers and small bunches — reduced yield across the crop.
- Toppling of plants that have lost their anchorage in a bored corm.
- Introduction and spread of the weevil through infested suckers to new plantings.
When to act
- The decisive step is at planting — use clean, pest-free suckers or tissue-culture plants, since the weevil mostly arrives with the sucker.
- Inspect and pare suckers before planting, and monitor the plant base for adults during the crop.
- Keep on top of it in older plantations, where the weevil builds up over successive cycles.
Organic & cultural control
- Plant clean, pest-free suckers or tissue-culture plants; pare (trim) the corm of suckers to remove any grubs before planting.
- Maintain base hygiene — remove and destroy infested corms and crop residue, and do not leave cut stumps and corms lying as breeding sites.
- Set corm/pseudostem traps at the plant base to attract and collect the nocturnal adults, and destroy them.
- Avoid deep planting and excess suckering, and rotate away from banana on badly-infested land.
Chemical control
- A recommended pre-plant sucker/corm treatment with a CIB&RC-registered insecticide protects the establishing plant from corm attack.
- Because the grubs are inside the corm, sucker treatment and trapping the adults work far better than a foliar spray.
- Observe the pre-harvest interval and any soil/corm treatment restrictions on the label.
- Confirm the current recommendation and treatment for your area with your local KVK or horticulture department.
Crops most at risk
Where this problem is called out in our crop guides — open a crop for the full package of practices.
Frequently asked questions
My banana plants grow poorly, make small bunches and topple. What causes it?
That combination — poor growth, weak suckers, small bunches and toppling — points to the banana rhizome (corm) weevil. Its grubs tunnel the corm at the base, destroying the tissue that anchors the plant and feeds root and shoot growth. Cut the corm and you will find dark tunnels and white grubs. Clean suckers and corm paring are the key controls.
How does the corm weevil get into a new plantation?
Mostly on infested suckers. The weevil and its grubs travel in the corm of planting material, so an infested sucker introduces the pest to the new field. Using clean, pest-free suckers or tissue-culture plants — and paring/treating the corm before planting — is the single most effective way to keep it out.
How do I control it in an established plantation?
Trap the nocturnal adults with corm or pseudostem traps at the plant base and destroy them, maintain strict base hygiene by removing infested corms and not leaving cut stumps as breeding sites, and avoid deep planting and excess suckering. On badly-infested land, rotate away from banana. Confirm any recommended treatment with your KVK.
Symptoms and control measures follow ICAR, KVK and state agricultural-university package-of-practices; any named chemical is a registered use. Always read the product label and confirm the dose for your crop and zone. editorial policy.