Maize Fall Armyworm Control

Symptoms

Young larvae scrape the leaf surface leaving small papery windows, then larger larvae feed inside the central whorl creating ragged elongated holes and leaving large amounts of moist sawdust like droppings in the whorl. A single fat caterpillar with a pale upside down Y mark on the head and four dots in a square on the second last segment is usually found inside the whorl. Later it can bore into cobs.

Damage

Fall armyworm is a serious invasive pest of maize in India since 2018 and can severely damage the whorl and growing point, killing young plants or stunting them, and damage to cobs reduces both yield and grain quality. Damage is worst in the early whorl stage of the crop and losses can be very high if uncontrolled.

Organic & cultural control

Plough deep before sowing to expose pupae, sow on time over a community wide window and avoid staggered planting. Install pheromone traps to monitor moths and set up bird perches. Hand pick and crush egg masses and grown larvae early in the morning, and apply a little dry sand or ash into the whorl which kills larvae mechanically. Release egg parasitoids like Trichogramma and spray neem based products or a recommended biopesticide such as Bacillus thuringiensis or a Metarhizium based product on early larvae.

Chemical control

When larvae cross the action threshold in the whorl stage, spray a registered insecticide such as spinetoram 11.7 SC, emamectin benzoate 5 SG or chlorantraniliprole 18.5 SC, directing the spray into the whorl where the larvae hide. Rotate insecticide groups to prevent resistance. Always follow the product label dose, observe the pre harvest interval and consult your KVK or agronomist before spraying.

Always follow the product label, the recommended pre-harvest interval, and your local KVK or agronomist. Pesticide approvals change, so verify before use.

Prevention

Practise early and uniform community sowing, deep summer ploughing and crop rotation with non host crops like pulses. Intercrop maize with legumes which helps natural enemies, keep fields weed free and monitor with pheromone traps from the seedling stage. Early detection and action in the whorl stage gives the best and cheapest control.