White grub
A fat C-shaped root-chewing grub that kills plants in expanding patches — and the best control is trapping the adult beetles when they swarm at the first rains.
- Pest type
- Soil grub (beetle larva)
- Attacks
- Roots
- Worst in
- Monsoon (kharif) crops
- Main risk
- Root loss; expanding dead patches
Overview
White grubs are the larvae of chafer/scarab beetles — fat, whitish, C-shaped grubs with a brown head and three pairs of legs, living in the soil. They feed on roots, so affected plants wilt, yellow and die in patches that expand outward as the grubs move through the soil, and the plants pull out easily with the roots chewed away.
The pest has one great weakness: the adult beetles emerge together in large numbers at the first heavy monsoon rains and fly to nearby trees (neem, ber, khejri) to feed and mate at dusk. Collecting and destroying these beetles during their brief swarming window — a coordinated, village-wide effort — is the single most effective way to cut the next generation of grubs, far cheaper than fighting the grubs once they are in the soil.
How to identify it
- Patches of plants that wilt, yellow and die, expanding outward, with the plants pulling out easily because the roots are chewed off.
- Fat, whitish, C-shaped grubs (up to 3–4 cm) with a brown head in the soil around the roots when you dig up a dying plant.
- Swarms of brown chafer beetles on neem, ber and other trees at dusk right after the first monsoon rains.
- Damage concentrated in light, sandy soils and often worse on field margins near host trees.
The damage it does
- Roots chewed away so plants wilt and die in patches, thinning or gapping the stand — severe in groundnut, sugarcane and bajra.
- Expanding dead patches as grubs move through the soil to fresh roots.
- In sugarcane, weakened, easily-lodged canes and yield loss from root destruction.
- A heavy grub population can require replanting parts of the field.
When to act
- The critical window is the first heavy monsoon rain, when the adult beetles emerge and swarm — this is when a community beetle-collection drive pays off most.
- Scout light-soil fields and margins near host trees, and dig in wilting patches to confirm grubs early.
- Seed/soil treatment decisions are made at sowing of the kharif crop, before the grubs establish on the roots.
Organic & cultural control
- Organise a village-wide beetle collection at the first monsoon rains — shake host trees at dusk and destroy the beetles, or set up light traps to catch the swarming adults; this is the highest-impact step.
- Deep summer ploughing exposes grubs and pupae to the sun, birds and predators, and reduces the carry-over population.
- Apply well-decomposed manure only (raw manure attracts egg-laying), and follow crop rotation to break the cycle.
- Apply entomopathogens — Metarhizium anisopliae or entomopathogenic nematodes — to the soil where available.
Chemical control
- A registered insecticidal seed treatment at sowing protects germinating groundnut and other kharif crops on grub-prone soils — the standard preventive.
- CIB&RC-registered soil applications and seed treatments (as registered for the crop) are used where grub pressure is known; apply strictly per the label.
- Light-trap-based adult beetle control, combined with soil treatment, works better than trying to reach established grubs deep in the soil.
- 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
Plants in my groundnut field are dying in expanding patches and pull out with no roots. What is it?
That is classic white grub damage — the fat C-shaped grubs live in the soil and chew off the roots, so plants wilt and die in patches that spread as the grubs move. Dig up a dying plant and you will find the whitish grubs. The key control is collecting the adult beetles when they swarm at the first monsoon rains.
Why is collecting the beetles at the first rains so important?
Because it is the one time the pest is exposed and easy to hit. The adult beetles emerge together and swarm on host trees at dusk after the first heavy monsoon rain; collecting and destroying them then — ideally village-wide — drastically cuts the eggs, and so the grubs, for the whole season. Fighting the grubs later, deep in the soil, is far harder and costlier.
How do I protect a kharif crop from white grub?
Combine an area-wide beetle collection / light-trapping at monsoon onset with a registered insecticidal seed treatment at sowing on grub-prone light soils, deep summer ploughing, fully decomposed manure and crop rotation. Together these cut both the adults and the grubs. Confirm the current seed-treatment recommendation with your local 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.