An Ecological Study of Cabbage Looper and Imported Cabbageworm Populations on Cruciferous Crops in Southern California1
Author: OATMAN, EARL R.
Source: Journal of Economic Entomology, Volume 59, Number 5, October 1966 , pp. 1134-1139(6)
Publisher: Entomological Society of America
Abstract:Ecological studies of the cabbage looper, Trichoplusia ni (Hübner), and imported cabbageworm, Pieris rapae (L.), on cruciferous crops were conducted in southern California during 1963-64. Eggs, larvae, and pupae were collected at random from consecutive plantings for I hour at weekly intervals for I year, and held for completion of del'e1opment and/or parasite emergence. Totals of 566 cabbage looper eggs and 2439 imported cabbageworm eggs were collected, of which 93.5% and 92.0% hatched, 5.6% and 7.5% failed to hatch, and 0.9% and 0.4% were parasitized for total egg mortalities of 6.5% and 7.9% respectively. The imported cabbageworm egg population reached a peak of 179 eggs per 1 hour search on July 30 and 72 eggs for the cabbage looper on August 6. Trichogramma pretiosum Riley was the only parasite reared from the egg stage. Totals of 1737 larvae and 68 pupae of the cabbage looper, and 960 larvae and 181 pupae of the imported cabbageworm were collected. Six generations of each species occurred during the year, with the imported cabbage- worm reaching a peak of 78 larvae per 1 hour search on July 24, and 130 for the cabbage looper on September 26. Twenty-six percent of the cabbage looper larvae were parasitized, of which 90% were by tachinids and 10% by hymenopterous parasites. Pupae were not parasitized. Twenty-three percent of the imported cabbageworm larvae and 51% of the pupae were parasitized for a total of 7470 parasitization. Tachinids accounted for 57% of the total larval and 5%of the pupal parasitization, and hymenopterous parasites 43% and 46% , respectively. Voria ruralis (Fallén) and Copidosoma truncatellum (Dalman) were the principal tachinid and hymenopterous parasites, respectively, on cabbage looper larvae, and Madremyia saundersii (Williston) and Apanteles glomeralus (L.) on imported cabbageworm larvae, Pteromalus puparum (L.) was the main pupal parasite of the latter. Altogether, 10 parasites were reared from the cabbage looper and 10 from the imported cabbageworm.
Document Type: Research Article
Publication date: 1966-10-01
- 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.
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