Characteristics of Armyworm Spodoptera litura (Fabricius) (Lepidoptera: Noctuidae) Occurrence and Control on Cotton

Abstract

In this paper, is examined the incidence of armywormSpodoptera litura(Fabricius)(Lepidoptera: Noctuidae), which is a highly polyphagous pest and inflicts serious damage to a wide spectrum of crops. The ability of S. liturato thrive on diverse host plants is an adaptive advantage for its survival in the ecosystem, which is achieved by its high mobility, fecundity and capacity to develop resistance to wide spectrum of chemical insecticides. Hosts of S. liturainclude field crops grown for food and fiber, plantation and forestry crops, as well as certain weed species.On most crops, damage arises from extensive feeding by larvae, leading to complete stripping of the plants. On cotton, the leaves are heavily attacked, bolls have large holes in them from which yellowish-green to dark-green larval excrement protrudes and yield of the crop is severely affected. Freshly hatched S. litura scrape the leaves from ventral surface, and full grown larvae feed on the leaves voraciously and present an appearance to the field as if grazed by livestock.Marigold is identified as suitable intercrop/border crop for pest management apart from harboring activity of major parasitoids of S. litura such as Microplitis sp., Cotesiasp., Campoletischlorideae and a polyembryonic parasitoid Copidosoma sp. Also grow castor as a border or intercrop or trap crop and set up pheromone trap to monitor, attract and kill the male moths @ 12/ha.Collect egg masses and destroy, also collect the gregarious larvae as well and destroy them as soon as the early symptoms of lace-like leaves appear on crop. Avoid migration of larvae by digging a trench 30 cm deep and 25 cm wide with perpendicular sides around the infested fields.Use of synthetic pyrethroids and endosulfan alternatively is effective against S. litura at 10% visual damage threshold and for managing 1^st to 3^rd instars larvae spray Emamectin benzoate 5 SG @ 11gma.i./ha or Spinosad 45 SC @ 75gm. For control of the 4^th to 6^th instars larvae, useIndoxacarb 14.5 SC @ 75gm ha^-1,Flubendiamide 480SC @ 48-60gma.i. ha^-1 orChlorantraniliprole 20 SC @30-40gm a.i. ha^-1. It is concluded that a combination of biological control agents, insect growth regulators, antifeedants, a trap crop and insecticides is an ecologically sound procedure for the control of S. litura.