The occurrence of pests has been reported by entomologists A S Vastrad and P S Hugar of the University of Agricultural Sciences, Dharwad and Shashidar Viraktamath, Emeritus Scientist. The study has confirmed the identity of the pest as Spodoptera frugiperda, a native of the Western Hemisphere commonly known as Fall armyworm.
Vastrad told TOI that outside its native range, the pest was first reported from the São Tomé and Príncipe islands and Nigeria in 2016 and spread across sub-Saharan Africa and established in 38 countries within two years. It has caused huge losses to staple cereals, especially maize and sorghum, affecting food security and trade. Damage to maize alone is estimated to be between $ 2.5-6.2 billion per year, he said. It is primarily a pest of maize but has a wide host range and is capable of feeding on over 80 plant species, periodically causing significant economic damage to rice, sorghum, millets, soyabean, wheat, alfalfa, cotton and fodder crops, Vastrad said.
“Initially the larvae cause shot-holes in the leaves and later they cause elongate irregular holes, cut the leaves halfway through, damage tassel and plug the whorls with yellowish-brown frass. Depending on the climatic conditions the Fall armyworm’s lifespan, from egg to larva to moth, lasts between one to three months. Controlling them is a challenge because they reproduce fast and in large numbers, can migrate great distances, hide within growing leaves and have been reported to resist several pesticides,” he said.
P S Hugar pointed out that for the past two years several reports have highlighted the outbreak of stem borer and oriental armyworm devastating maize crop. Present outbreak of the new pest will only add to the miseries of maize farmers, who have to bear the additional cost of plant protection. Emergency responses by affected farmers, mainly based on the use of pesticides may prove costly and not very effective, he cautioned. Though interventions used elsewhere could be used, quick local adaptations need to be developed. Use of bio-pesticides, botanicals and alternating sprays of old and newer insecticides is advocated in the absence of the integrated pest management (IPM) strategies, Hugar said.