Sesame leaf webber & capsule borer
Sesame’s key pest — webs the top shoots and feeds inside, then bores the flowers and capsules, striking from shoot to seed.
- Pest type
- Webbing/boring caterpillar
- Attacks
- Shoots, flowers, capsules
- Worst in
- Warm sesame season
- Main risk
- Webbed shoots; bored seed capsules
Overview
The sesame leaf webber and capsule borer (Antigastra) is the most important pest of sesame (til), and unusual in attacking the crop at essentially every stage. Early on, the caterpillar webs together the tender top leaves and growing shoots with silk and feeds inside the webbed cluster, killing the shoot tips.
As the crop flowers and sets, the same caterpillar bores into the flowers and then into the developing capsules, eating the seed inside. So a single pest damages the shoots, the flowers and the seed capsules in turn, and because it feeds sheltered inside webbing and capsules, timing control to the young, exposed stage matters more than late spraying. It is favoured by the warm conditions of the sesame season and builds up quickly.
How to identify it
- Top leaves and shoots webbed together with silk, with a caterpillar feeding inside the cluster and the shoot tips dying.
- Bore holes in the flowers and in the developing capsules, with the seed eaten inside.
- Small greenish caterpillars inside the webbing and capsules.
- Damage progressing from the shoots early to the flowers and capsules as the crop matures.
The damage it does
- Webbed, killed shoot tips that reduce growth and branching early in the crop.
- Bored flowers and capsules with the seed eaten — direct loss of the harvested seed.
- Attack at every stage from shoot to capsule, so an unmanaged infestation compounds losses.
- Sheltered feeding inside webbing and capsules that makes late control difficult.
When to act
- Scout from early growth for webbed shoot tips, and again at flowering–capsule set for bored flowers and capsules.
- Act at the young-caterpillar stage before it is sheltered deep in webbing or inside a capsule.
- Protect the flowering to capsule-development window, when seed loss is decided.
Organic & cultural control
- Remove and destroy webbed shoot tips early to take out the sheltered caterpillars.
- Spray neem (NSKE 5%) on young larvae and use Bt against the exposed young stage.
- Grow recommended tolerant varieties, sow at the recommended time, and destroy crop residue after harvest.
- Conserve natural enemies by avoiding unnecessary broad-spectrum sprays.
Chemical control
- Target young larvae before they web up or bore in — CIB&RC-registered insecticides for sesame, timed to shoot webbing and to flowering–capsule set.
- Good coverage of the top shoots and flowers is needed to reach the caterpillars; rotate insecticide groups.
- Observe the pre-harvest interval on the seed crop.
- Confirm the current recommendation and dose for your area 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 top shoots of my sesame are webbed together and dying. What is it?
That is the sesame leaf webber and capsule borer (Antigastra), the key pest of sesame. The caterpillar webs the tender top leaves and shoots and feeds inside, killing the tips. The same pest later bores the flowers and seed capsules. Remove webbed shoots early and target the young caterpillars before they shelter deep in webbing or capsules.
Why is this pest so damaging to sesame?
Because one caterpillar attacks the crop at every stage — webbing and killing the shoots early, then boring the flowers and the seed capsules later, eating the seed itself. And because it feeds sheltered inside webbing and capsules, it is hard to reach once established. That combination of stage-long damage and hidden feeding makes it sesame’s most important pest.
When should I control it?
Act at the young-caterpillar stage — remove webbed shoot tips and treat young larvae before they shelter in webbing or bore into capsules — and protect the flowering to capsule-development window, when seed loss is decided. Use neem/Bt early and a rotated registered insecticide on threshold, with good coverage of the top shoots and flowers.
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.