Fall Armyworm (Lepidoptera: Noctuidae) Infestations in No-Tillage Cropping Systems

Field experiments comparing no-tillage and plow-tillage practices demonstrated that infestations by the fall armyworm, Spodoptera frugiperda (J. E. Smith), ultimately become similar in either cropping system. However, in certain no-tillage situations where high mulch concentrations were present on the soil surface, oviposition and damage were reduced. Significantly fewer egg masses and damage were sampled on corn, Zea mays L., (3-leaf stage) while seedlings remained within no-tillage mulch. Oviposition quickly became similar to that observed in plow-tillage systems when the plants grew above the mulch canopy of no-tillage. The number of egg masses on corn older than 4 leaves was similar in either cropping system, and leaf injury at plant silking was the same. In a comparison of corn, sorghum (Sorghum bicolor [L.] Moench.), and soybeans (Glycine max L.), the latter crop had no damage in either tillage system while corn and sorghum were heavily infested. Efficacy of chlorpyrifos (0.56 kg [AI]/ha) for controlling fall armyworm leaf damage was similar in corn and sorghum in either cropping system.