The Fall Army Worm, a pest with a roaring appetite has been sweeping through Africa leaving losses in its wake. A strong flier, the pest has managed to move seamlessly from country to country mainly affecting maize which is a staple in many African countries. Laying up to 1,000 eggs in a span of 10 days, they are as resilient as bedbugs only that their menu us green, including maize, sorghum millet, vegetable crops etc.
The Fall Army Worm has for some time been causing havoc in Brazil before getting into Africa (hence the reason for Kenya sending a delegation to Brazil to learn how to control the worm earlier this year). They have been reported in Zimbabwe and Malawi, Nigeria in West Africa to Kenya in East Africa, among tens of other nations.
In Kenya, the Fall Army Worm was spotted in the first quarter of 2017 and has caused losses in Trans Nzoia county who are the main producers of maize in the country. Here are practices that can help you survive the crop as per the Crop Health division of the Kenya Agricultural and Livestock Research Organisation (KALRO).
Plant early, observe the planting calendar of your region, avoid late or planting in the offseason. This allows your maize to mature before the population of pests builds up, plants are most vulnerable when young and the Fall Army Worm favours attacking plants before they have silked (picture below), thus if your plants are young when the neighbours’ are older, the worm will likely favour attacking yours.
The soil harbours the pest, thus make sure you plough and let your land lie idle for a while before planting, additionally, deep ploughing can expose the pests hiding in the soil to predators like birds. Ensure your fields are weed free, weeds are to pests what forests are to a soldiers-the perfect hiding ground.
Monitoring and Early Action
The Army Worm can only be controlled when the Larvae are still small, thus start inspection one week after germination. Watch out for cream/grey egg bundles covered in a layer of grey-pink scales on leaves’ underside, in addition to green/black or brown larva. A mature Fall Army Worm has a white line between the eyes forming an overturned Y pattern on its face. Additionally, it has four black spots forming a square in the tail end. Search for ragged and elongated holes on the leaves and young plants that coil inward.
Monitor damage on 10 consecutive plants in 10 randomly selected sites. Apply relevant measures if 10% of plants are infested
Put up fall armyworm pheromone traps to subdue moth populations, one trap per hectare, this will lead to a reduction in laid eggs and larvae. Pheromone traps can also be used in monitoring and early warning as you will detect trapped moths once they invade your farm.
Restrict movement of infected plants
Once you have detected infected plant material and want to destroy it or feed livestock with it, do it as close as possible to the infected farm. Do not transport it to places where you haven’t detected the pest.
The Fall Army Worm can be chemically controlled on a temporary basis, KALRO recommends synthetic pesticides with the following ingredients, diazinon, alpha cypermethrin, chlorpyrifos, flubendiamide, chlorantraniliprole, and lambda cyhalothrin. Additionally you can use organic biopesticides based on Bacillus thuringiensis.