Management and Control of Fall Armyworm in Maize, A serious problem for farmers in Pakistan

Fall armyworm is a type of armyworm. Its native area is America and Argentina. Its attack was observed first time in 2016 in central Africa and then this insect moved to India and China in 2018. In 2020 its attack was seen in Punjab, especially in Bahawalnagar, Sahiwal, Okara and Chiniot. Now it is present in almost all maize-growing areas of Pakistan and has become a serious problem for farmers. Recently it becomes the main enemy of maize crops. These insects attack the crop from the seedling stage through the different stages of its maturity thus causing significant damage to the crop.

The life span of Fall Armyworm

The lifecycle of the Fall armyworm includes an egg, 6 growth stages of Caterpillar development (instars), a pupa and a moth.

100-200 eggs are generally laid on the underside of the leaves of maize plants which are typically near to the base of the plant. These eggs are covered by protective scales which is rubbed off from the moth’s abdomen. In case of insect populations are high then the eggs may be laid higher up the plants or maybe also on nearby vegetation.

GROWTH STAGES 1-3

After hatching the young caterpillars feed superficially, usually on the undersides of leaves. The colour of the first growth stage caterpillars is light green with dark brown heads. When grown to the third growth stage comes the colour changes with yellow strips on the body. The period taken by then to change from the first to third growth stage is 18-30 days. During these stages, caterpillars get identified as Fall armyworminsect. When they feed on plant leaves results in semitransparent patches called windows. Young caterpillars can spin silken threads which catch the wind and caterpillars hang on them to get transportation from one plant to another. Feeding is more active during the night time or at dawn.

GROWTH STAGES 4-6

When caterpillars feed on young plants they can kill the growing points of the plants resulting in no new leaves or no cob development.

Pupa

The caterpillar before going to the pupa burrow 2-8 cm into the soil. The oval cocoon which is loose and silky is formed with a length of 20-30 mm. If the soil is too hard then the caterpillar will cover itself in leaf debris before pupating.

Moth

The adult moth emerges after 8-10 days to restart the lifecycle. The colour of the moth is brown. The male has a prominent character with white triangle patches on the forewings while the hindwings are similar in both males and females.

Ways to control Fall Armyworm

There are different ways to control Fall Armyworm, the most important ones are given here

Prevention

The best way to control Fall Armyworm caterpillars is to prevent infestation of farms.
Plant the maize on the onset of rain.
Intercrop maize with another crop, which is not a susceptible host of Fall Armyworm like soybean.
Make weed-free fields of maize and surrounding regularly.
Ensure the crop with the right time application of fertilizer, well fertilize the field.

Monitor

Regularly closely monitor the field. Monitor right from germination, two times a week when the leaves become naked from the soil.

Identification

Adult females change from green to light brown before hatching.
After hatching, the young caterpillars begin feeding on the leaves. As they grow, caterpillars change from light green to brown.
There are four dark spots in a square form on the second last segment. Fall armyworms have a dark head with a Paley shape on the front.
The pupa is shiny brown. Adult moth females are slightly bigger than males.