Economic thresholds for imported cabbageworm (lCW), Artogeia rapae (L.), cabbage looper (CL), Trichoplusia ni (Hübner), and diamondback moth (DBM), Plutella xylostella (L.), larvae on cauliflower, Brassica oleracea var. botrytis (L.) (Papaverales: CrucHerae), were evaluated at Cambridge, Ont. Four treatments were tested in 1985: a control, a biweekly application of permethrin, and permethrin after thresholds of 0.5 cabbage looper equivalents (CLE) per plant per week were surpassed during the growth interval from transplanting to harvest or from head initiation to harvest (one CLE = 1.0 CL = 1.5 ICW = 20 DBM). Five treatments were tested in 1986: a control, a biweekly application of permethrin, and permethrin after head initiation and after thresholds of 0.25, 0.5, or 1.0 CLE per plant per week were reached. Head weight, diameter, and marketability did not differ significantly between plots managed in 1985 with the 0.5 CLE threshold imposed from transplanting to harvest and from head initiation to harvest. Control measures, therefore, need not be implemented until after head initiation. There were no significant differences in weight, diameter, and marketability of heads harvested from the biweekly treatment and the 0.25 CLE threshold in 1986. Revenue, the difference between pest control costs and crop value, for the 0.25 CLE threshold was $48.54/ha greater than that for the biweekly treatment.
Document Type: Research Article
Publication date: December 1, 1988
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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.