Chemical Control of the Fall Armyworm (Lepidoptera: Noctuidae): An Update

Abstract

Fall armyworm (FAW), Spodoptera frugiperda (J. E. Smith), populations in the southeastern United States are resistant to carbaryl, methyl parathion, trichlorfon, and diazinon, whereas FAW in the mid-south and west of the Mississippi River do not appear to have a high level of resistance to these insecticides. Methomyl has been effective in all areas, but the level of susceptibility in Florida may be declining. The efficacy of insecticide treatments in some crops appears to be related to plant coverage by spray application. Carbaryl, methyl parathion, and permethrin spray applications are reported to be more effective on FAW larvae feeding on seed heads than in the whorls. Chlorpyrifos, sulprofos, and thiodicarb are relatively new materials that have proved to be effective against FAW in many areas, while the synthetic pyrethroids have provided erratic control of FAW larvae. Combinations of pyrethroids and chlorpyrifos at rates lower than recommended give effective FAW control. Resistance or moderate to low levels of resistance to carbaryl, phoxim, methyl parathion, trichlorfon, and/or methomyl have been reported in some areas of Central and South America. Spray applications are most effective when high volumes of aqueous carrier are used with either ground, chemigration or air equipment. Ground equipment with the higher water rates provides higher levels of insect control. Insecticide granules applied in the whorl are effective and may provide an increased level of control of FAW larvae compared to some recommended aqueous spray applications.