Fall Armyworm (FAW) or Spodoptera frugiperda, is a polyphagous lepidopteran and a gregarious eater and destructive pest of maize crop. Originating from South America, the pest has spread all over the globe. The European Union recognizes the pest as a quarantine pest, which established its dominance in African maize fields during 2016. In mid-2018 Indian invasion began, starting from the Southern region in Karnataka, and metastasizing to Central, Eastern and North-Eastern regions as well.
“Fall Armyworm is a crop-guzzling pest that derives its name from army as it invades crop in masses, much like an army”
How FAW multiplies?:
(Fall Army Worm) FAW’s ability to spread at a rapid pace arises from its reproductive and adaptive capabilities. The life cycle begins when the female adult moth elicits mating calls to attract the male moths. Post engaging in mating, the female adult moth embarks to lay egg-mass, either on the base of the plant stem, below or above the leaves. Egg-mass usually comprise of 50-200 eggs and covered with protective scales from female moth’s abdomen. Eggs hatch within 7-12 days and out come the neonate larvae, resulting in the outset of ferocious eating ceremony, going on through the larval phase of development.
Spread of FAW:
“Fall armyworm has rapidly spread across maize growing States since it was detected in Southern India in late mid-2018. Most of countries in Asia including Bangladesh, China, Indonesia, Myanmar, Nepal, Sri Lanka, Taiwan and Vietnam have reported severe infestation of FAW in last one year”
Damage by FAW:
The neonate larva while feeding on the superficial leaf surface, produce the characteristic windowing effect. These larvae also spun silk threads which are carried by wind to neighboring plants by winds. Larval feeding varies with the plant developmental stages, wherein the maturing larvae move from the foliage to whorl as the plant undergoes different Vegetative stages of development. Additionally, as the feeding moves from foliage to whorl, the nature of damage changes as well. The foliar damage also shows varied forms such as pin-point holes, scratches, whereas the leaves emerging from damaged whorl show large ragged holes in a paper doll pattern.
It is the larval stage of FAW which inflicts severe damage, which if not controlled, can bring entire season’s produce to waste. The pest thrives best around a temperature of 25-30 degree Celsius, whereas development slows down at colder temperatures.
Target Crops of FAW:
Besides the maize plant, which is the most favored food, FAW can feed on an exhaustive range on vegetable crops and grasses such as bermudagrass, crabgrass, Digitaria spp. Beside frequent attacks on field maize, sweet corn and baby corn. The field crops such as alfalfa, buckwheat, barley, maize, cotton, clover, millet, rice, maize, peanut, sorghum, ryegrass, Sudan grass, Sugar beet and sugarcane etc.
“Fall Armyworm, a polyphagous preferably feed on maize and can affect and cause heavy losses to many crops including maize, sweet corn, baby corn, sorghum, millets, sugarcane etc.”
As the pest can adapt to a large number of host plants, exhibits expansion in taste receptor genes, ability to migrate to fields during the night, combined with strong flight abilities of adult moths, make FAW a pest of high danger amongst other factors.
Hence, to protect produce from FAW, prevention is better than cure.