The fall armyworm, Spodoptera frugiperda (J. E. Smith), is a serious pest of corn in Maryland. To estimate the relationship between number of larvae per plant and plant weight at two plant growth stages for single-cultivar stands of silage corn, field experiments were conducted in 1988 and 1989. In 1990, single- and mixed-cultivar stands at mid-whorl were compared. Significant reductions in plant weight as a function of larval density (5, 10, 15, and 20 second instars per plant) were observed for artificial infestations at mid-whorl and late-whorl stage corn. No relationship between larval density and plant weight was detected for the mixed-cultivar stand infestation at mid-whorl stage. Using the observed relationships of plant weight and number of larvae per plant, crop value of 988/ha, and management cost of 37/ha, economic injury levels were set at two secondinstar fall armyworms per plant for mid-whorl infestations during 1988, 1989, and 1990 and for late-whorl infestations in 1988 and 1989.
Document Type: Research Article
Publication date: August 1, 1993
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Journal of Economic Entomology is published bimonthly in February, April, June, August, October, and December. The journal publishes articles on the economic significance of insects and is divided into the following sections: apiculture & social insects; arthropods in relation to plant disease; forum; insecticide resistance and resistance management; ecotoxicology; biological and microbial control; ecology and behavior; sampling and biostatistics; household and structural insects; medical entomology; molecular entomology; veterinary entomology; forest entomology; horticultural entomology; field and forage crops, and small grains; stored-product; commodity treatment and quarantine entomology; and plant resistance. In addition to research papers, Journal of Economic Entomology publishes Letters to the Editor, interpretive articles in a Forum section, Short Communications, Rapid Communications, and Book Reviews.