1985 Fall Armyworm Symposium: Migration and Population Dynamics: Adult Sampling as a Means of Predicting Damage Levels of Fall Armyworm (Lepidoptera: Noctuidae) in Grain Corn

James J. Linduska, Floyd P. Harrison

Abstract


Any attempt to correlate adult fall armyworm, Spodoptera frugiperda (J. E. Smith) captures with infestation is complicated because plant maturity at the time migrating moths arrive in Maryland determines the extent to which larvae infest and damage corn, Zea mays L. Plants in mid-whorl and older escape injury whereas younger plants become infested. This work attempts to explain the difference maturity makes in susceptibility to fall armyworm and to correlate moth trap catches in pheromone traps with percent plants becoming infested. Observations in 4 separate plantings indicated the number of neonate larvae is reduced when Pioneer 3184 grain corn attained a maturity level of ca. 40% tassle-height ratio. The time from emergence from the soil to 40% T-H was hypothesized as a susceptible period. A regression analysis of % plants infested and moths captured in pheromone traps during this susceptible period resulted in a significant regression and an r^2 of 0.87.

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