Spotted pod borer (Maruca)
The pulse borer that webs flowers and pods together and feeds hidden inside — sheltered from both sprays and predators.
- Pest type
- Webbing caterpillar
- Attacks
- Flowers, buds, pods
- Worst in
- Flowering & podding
- Main risk
- Hides in webbing; bores pods
Overview
The spotted pod borer, Maruca vitrata, is one of the most damaging pests of pigeonpea (arhar), moong and urad, striking exactly at flowering and podding. Its trademark is silk: the caterpillar ties together flowers, buds and young pods into a webbed cluster and feeds inside it.
That webbing is what makes it hard to control — hidden inside the mass, the caterpillar bores buds and pods while sheltered from both insecticide sprays and natural enemies. The damage is concentrated on the reproductive parts, so even a modest population at flowering can cause heavy pod loss. Timing control to flowering, before the caterpillars retreat into the webbing, is the key.
How to identify it
- Flowers, buds and young pods webbed together with silk into a loose cluster — the surest field sign.
- Inside the webbing, a pale caterpillar with rows of dark spots along the body (hence "spotted").
- Bored buds and pods with entry holes and frass, and dropped or dried flowers where the caterpillar has fed.
- Damage peaks right at the flowering–early-podding stage of the pulse crop.
The damage it does
- Webbed and bored flowers, buds and pods — direct loss of the flowers and pods that would have set seed.
- Concentrated attack at flowering means heavy proportional yield loss even from moderate numbers.
- The webbing shelters the caterpillar from sprays and predators, so untreated infestations build fast.
- Secondary rot enters bored pods, spoiling more of the seed.
When to act
- Watch the crop closely from bud initiation through flowering — this is when Maruca does its damage and when control is still possible.
- Scout for the first webbed flowers and young caterpillars; act before they retreat deep into a webbed pod cluster.
- Pheromone traps for Maruca help time the moth flights and egg-laying so sprays land on young larvae.
Organic & cultural control
- Spray neem (NSKE 5%) at flower initiation to deter egg-laying and check young larvae before they web up.
- Use Bacillus thuringiensis (Bt) against young caterpillars while they are still exposed on the flowers.
- Set pheromone traps to monitor, and grow recommended tolerant varieties where available.
- Deep-plough after harvest and rotate crops to reduce carry-over of pupae.
Chemical control
- Time the spray to flowering, when larvae are young and exposed — once webbed inside pod clusters they are protected.
- CIB&RC-registered options for pulse pod borers include flubendiamide 39.35% SC, chlorantraniliprole 18.5% SC, indoxacarb and spinosad — chosen for your crop.
- Get thorough coverage into the flowers and use a good spray volume; rotate insecticide groups to avoid resistance.
- Confirm the current recommendation and dose for your crop and zone with your local KVK.
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
The flowers and pods on my arhar/moong are webbed together. What is it?
That silk webbing binding flowers, buds and young pods is the signature of the spotted pod borer, Maruca vitrata. The caterpillar feeds hidden inside the webbed cluster, boring the buds and pods. Because it shelters in the webbing, time your control to flowering, before it retreats inside.
Why is Maruca so hard to control?
Because it hides inside a silk webbing of flowers and pods, sheltered from both sprays and natural enemies. The answer is timing and coverage: act at flowering while the young caterpillars are still exposed, use neem and Bt early, and get a registered insecticide thoroughly into the flowers before the webbing forms.
When should I spray for spotted pod borer?
At flowering to early podding — that is when Maruca attacks and when the young larvae are still exposed and reachable. Monitor with pheromone traps to time it, start with neem or Bt, and reserve a rotated registered insecticide for when numbers cross threshold. Spraying after the pods are webbed and bored is largely too late.
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.