Banana pseudostem weevil
Its grubs tunnel the banana pseudostem from inside — the plant weakens, oozes gum, and can snap under the bunch before the damage is even obvious.
- Pest type
- Stem-boring weevil
- Attacks
- Pseudostem (inside)
- Worst in
- Older / ratoon banana
- Main risk
- Tunnelled, toppling stems
Overview
The banana pseudostem weevil is a serious hidden pest of banana. The adult is a reddish-brown to black weevil that lays eggs in the pseudostem; the grubs bore into it and tunnel extensively, creating a network of galleries inside the stem while the outside can look almost normal at first.
As tunnelling advances, the pseudostem oozes a gummy sap from the bore holes, the plant weakens, growth and bunch development suffer, and a badly-bored stem can snap or topple — especially once it carries the weight of a bunch. Because the grubs work inside the stem, the weevil is hard to reach with sprays, so control rests on using clean pest-free suckers, field and crop hygiene, trapping the adults, and destroying infested plants and residue.
How to identify it
- Small bore holes on the pseudostem oozing a gummy or watery sap — an early external sign of grubs tunnelling within.
- When a suspect pseudostem is cut, a network of galleries and tunnels packed with rotting tissue, with grubs inside.
- Weakened plants with poor growth and bunch development, and stems that snap or topple, especially when bearing.
- Reddish-brown to black weevils in the leaf sheaths and around the base.
The damage it does
- Extensive internal tunnelling of the pseudostem that weakens the plant and disrupts growth and bunch filling.
- Gum ooze and rotting tissue inside the stem, opening it to secondary rots.
- Snapped or toppled plants, particularly once they carry the weight of a bunch — a direct crop loss.
- Build-up in older and ratoon plantations and spread through infested suckers.
When to act
- Start clean — select pest-free suckers/tissue-culture plants, since the weevil spreads on infested planting material.
- Inspect pseudostems for gum-oozing bore holes from the vegetative stage, especially in older and ratoon crops.
- Act on the first infested plants and keep the plantation clean, rather than waiting for toppling.
Organic & cultural control
- Use clean, pest-free suckers or tissue-culture plants, and avoid taking suckers from infested clumps.
- Maintain field hygiene — remove and destroy severely infested pseudostems, harvested stems and crop residue where the weevil breeds.
- Set pseudostem trap-splits (cut pieces of pseudostem) to attract and collect the adult weevils, and destroy them.
- Avoid excessive suckers per clump and manage the ratoon so old, weevil-prone stems do not accumulate.
Chemical control
- Where infestation is significant, CIB&RC-registered insecticides for the crop can be applied to the leaf sheaths/pseudostem as recommended, since the grubs are inside.
- Trap-and-destroy of adults with pseudostem traps, combined with hygiene, does much of the work; a blanket spray reaches the internal grubs poorly.
- Observe the pre-harvest interval on the fruit.
- Confirm the current recommendation and method 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 pseudostems ooze gum and some plants have snapped. What is it?
That gum ooze from bore holes and the snapping of stems is the banana pseudostem weevil. Its grubs tunnel extensively inside the pseudostem, weakening it so it oozes gum and can topple, especially under the weight of a bunch. Cut a suspect stem and you will find galleries and grubs inside. Use clean suckers and remove infested stems.
Why is this weevil hard to control with sprays?
Because the grubs do their damage inside the pseudostem, protected from anything sprayed on the surface. That is why control leans on clean, pest-free planting material, field hygiene (removing infested and harvested stems), and pseudostem traps to catch the adults — with any recommended insecticide applied to the sheaths as a supplement, not the mainstay.
How do I stop it building up in my plantation?
Start with pest-free suckers or tissue-culture plants, do not take suckers from infested clumps, and keep the field clean by destroying severely infested and harvested pseudostems and residue where the weevil breeds. Use pseudostem trap-splits to collect adults, and manage the ratoon so old weevil-prone stems do not pile up.
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.