Jassids (leafhoppers)
Wedge-shaped green hoppers whose toxic saliva yellows, bronzes and curls leaf edges downward — the "hopper burn" of cotton and brinjal.
- Pest type
- Sap-sucking hopper
- Attacks
- Leaf undersides
- Worst in
- Warm, humid weather
- Main risk
- Hopper burn (toxic saliva)
Overview
Jassids, or leafhoppers, are small (about 3 mm) green, wedge-shaped insects that rest on the underside of leaves and characteristically walk or hop sideways when disturbed. Both adults and the pale wingless young suck sap.
Unlike a plain sap-sucker, the jassid injects toxic saliva as it feeds. This blocks the leaf’s vascular tissue, so the leaf margins first yellow, then bronze and finally curl downward and dry — a symptom called "hopper burn" that can scorch a whole cotton or brinjal field from the edges in. Susceptible varieties suffer far more than hairy-leaved tolerant ones.
How to identify it
- Small green, wedge-shaped insects on the leaf underside that move or hop sideways when you disturb the leaf.
- Pale green, wingless young (nymphs) that also walk sideways, found alongside the adults under the leaf.
- Leaf margins yellow, then bronze/redden and curl downward — "hopper burn" — starting at the leaf tips and edges.
- In cotton, run a hand over the crop at dusk and watch the adults flick up; tolerant hairy-leaved varieties show far fewer.
The damage it does
- Yellowing, bronzing and downward cupping of leaf margins that spreads inward and dries the leaf ("hopper burn").
- Stunted, hardened plants with reduced flowering and boll/fruit set when the attack is early.
- In cotton, an early hopper attack on young plants is one of the most yield-limiting sucking-pest problems of the season.
- Repeated feeding weakens the plant and opens it to secondary stress.
When to act
- Scout leaf undersides twice a week from the seedling stage; cotton is most vulnerable in the first 60–70 days.
- Economic thresholds are commonly set around 2 nymphs per leaf on the lower/mid canopy in cotton — check the local recommendation.
- Grade the crop by the hopper-burn scale (leaf yellowing/curling); act before curling sets in, as burnt leaves do not recover.
Organic & cultural control
- Grow tolerant, hairy-leaved cotton varieties — leaf hairiness is the single most effective defence against jassids.
- Spray neem oil / NSKE 5% early, which repels hoppers and is soft on their natural enemies (spiders, mirid bugs, lacewings).
- Avoid excess nitrogen, which produces the soft lush growth hoppers prefer; keep plant spacing open for good spray reach.
- Conserve natural enemies by avoiding early broad-spectrum sprays that trigger later pest resurgence.
Chemical control
- Where nymph counts cross the threshold, use a CIB&RC-registered insecticide such as imidacloprid 17.8% SL, thiamethoxam 25% WG, flonicamid 50% WG or acetamiprid — registered for your crop.
- A neonicotinoid seed treatment in cotton protects the crop through the vulnerable early weeks and reduces early sprays.
- Rotate insecticide groups, spray the leaf undersides, and observe the label pre-harvest interval on vegetables.
- 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
My cotton leaf edges are turning yellow-red and curling down. What is it?
That downward curling with yellow-to-bronze margins is "hopper burn", caused by jassids (leafhoppers) injecting toxic saliva as they suck sap from the leaf underside. Check the undersides for small green wedge-shaped insects that hop sideways. Burnt leaves do not recover, so act before the curling spreads.
Why do some cotton varieties get far fewer jassids?
Leaf hairiness. Hairy-leaved cotton varieties physically deter jassids from settling and feeding, so they suffer far less hopper burn than smooth-leaved ones. Choosing a tolerant hairy variety is the cheapest and most durable jassid control you can apply.
When is the crop most at risk?
Early — cotton is most vulnerable to jassids in roughly the first 60–70 days. A neonicotinoid seed treatment plus early scouting protects this window; after that, natural enemies and tolerant varieties carry more of the load. Act on threshold counts before hopper burn sets in.
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.