The influence of the larval parasite Bathyplectes curculionis (Thomson) upon the population of the alfalfa weevil, Hypera postica, in lowland middle California from the time the former was introduced in 1933 and 1934 through 1938 has been previously discussed, Michelbacher (1940). Since that time the investigation has been continued. In lowland middle California the alfalfa weevil is found in three areas having different climates. These are: The region adjacent to the San Francisco Bay, the agricultural area surrounding Pleasanton, and the northwest portion of the San Joaquin Valley. The regions are contiguous, but are separated from one another by ranges of hills, and the climate becomes more continental from the first to the last named region. It has been found that B. curculionis is most effective in the areas having the more moderate climates. In these climates the period of adult parasite activity is longer than in the more severe climate of the San Joaquin Valley. The parasitism trends in 1939 substantiated substantiated the findings of previous years, and are graphically shown in figure 1. The graphs were prepared in the manner reported by Michelbacher (1940). In the region adjacent to the San Francisco Bay and in that about Pleasanton the amount of parasitism was high and the alfalfa weevil population was small. In the northwest portion of the San Joaquin Valley the degree of parasitism was less and the alfalfa weevil population was considerable.
Document Type: Research Article
Publication date: December 1, 1940
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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.