Weekly Economic Injury Levels for Fall Armyworm (Lepidoptera: Noctuidae) Infestation of Corn in Lowland Ecuador

Resumen

Fall armyworm, Spodoptera frugiperda (J. E. Smith), was controlled at weekly intervals in corn on Ecuador's coastal plain to determine the effect of plant stage on yield loss from pest injury. Greatest yield increases due to insecticide treatments occurred when plants were infested in the second week after germination; yields progressively decreased through tasseling. Economic injury levels calculated from a regression of these data increased from 11% to 42% infestation during the first 6 wk following plant emergence. Spray decisions based on economic injury levels linked to crop maturity could result in lower control costs than presently achieved with fixed economic injury levels.