In this paper the theory that there are at present two geographical races of the European corn borer, Pyrausta nubilalis, in America is discussed. Larvae transferred from New York to Massachusetts in 1920 have for four years maintained a single annual generation while larvae from Massachusetts that had a single generation during 1920 have been reared under the same conditions and have had a partial second generation each year. The fact that individuals in the infested area about Lake Erie are practically all large and well nourished while in New England many larvae enter hibernation in the fall half starved and from a third to a half smaller than normal larvae suggests the theory that the infestation about Lake Erie will be more dependable from year to year. This has proved to be the case during 1923 and 1924 when the New England infestation has decreased and the infestatton about Lake Erie has increased both as to spread and in intensity of infestation. There is also considered the theory that the New England infestation may be reverting to a single generation habit by a process of natural selection in view of an environment that will not support two annual generations.
Document Type: Research Article
Publication date: June 1, 1925
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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.