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 the 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.
Life span of Fall Armyworm
The lifecycle of Fall armyworm includes egg, 6 growth stages of Caterpillar development (instars), pupa and 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 first growth stage caterpillars is light green with dark brown heads. When grown to third growth stage comes the colour changes with yellow strips on the body. The time period taken by then to change from 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 with no cob development.
The caterpillar before going to 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.
Adult moth emerges after 8-10 days to restart the lifecycle. The colour of the moth is brown. Male has prominent character with white triangle patches on forewings while hindwings are similar in both male and female.
Ways to control Fall Armyworm
There are different ways to control Fall Armyworm, most important ones are given here
- 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.
Regularly close monitor the field. Monitor right from germination, two times in a week when the leaves become naked from the soil.
- 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.
Management and control
Fall Armyworm can be managed by using the following ways
- By preventing attack of Fall Armyworm.
- By using Intercropping technology
- Biological control
- Use of local substances
- Use of plant extracts and botanicals
- Use of physical methods
- Use of the chemical method
Chemical control of Fall Armyworm
- Pest scout the crop two times a week, and destroy the eggs or caterpillars that are found.
- Spray field with spinosid 240 SC at the rate of 80 ml/acre.
- Emamectin benzoate 1.9 EC at the rate of 200 ml/acre.
- Methoxy phenoxide 240 SC@ 200 ml/acre.
- Leufinoron 5% EC @ 200 ml/acre.
- Better control can be achieved by using the spray in combination like emamectin 1.9EC+leufinoron 5%EC at the rate of 200+200 ml/acre.· Fepronil+Emamectin benzoate 0.35 G@ 8 kg/acre.
Dr Haroon Zaman Khan
Dr Muhammad Ashfaq Wahid
Dr Muhammad Farrukh Saleem
Dr Asif Iqbal
Department of Agronomy, University of Agriculture Faisalabad
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