Susceptibility of the Fall Armyworm,<i>Spodoptera frugiperda</i>(Lepidoptera: Noctuidae), at Santa Isabel, Puerto Rico, to Different Insecticides

Abstract

The fall armyworm (FAW), Spodoptera frugiperda (J. E. Smith), is a polyphagous migratory pest, which is endemic to the Western Hemisphere and attacks more than 80 plant species including maize, sorghum, cotton, rice, millet, peanut, alfalfa, and other cultivated and wild plant species. Presence of multiple generations and the ability to migrate and feed on a wide range of host plants makes FAW one of the most severe economic pests throughout the Western Hemisphere. In corn, yield losses due to FAW damage can reach up to 32% in the United States and 45–60% in Nicaragua. Insecticides are used as major components of IPM to control the pest because its ability to migrate long distances and feed on a broad host range make other control options less efficient. Although chemical insecticides can provide effective control of crop pests including FAW, control of FAW has been fully dependent on insecticides, and, as a result, the pest has developed resistance to major classes of insecticides in several locations. In Puerto Rico, where many seed companies produce seed corn throughout the year, FAW is the number one pest, which makes it very difficult to get any yield without insecticide application. Insecticides are sprayed 3 times a week during the peak season, and up to 25 sprays have been made in one crop cycle, which places heavy selection pressure on the pest for development of insecticide resistance. The objective of the present study was to assess the susceptibility of Puerto Rico a FAW population to insecticides.