Greenbugs [Hom.: Aphididae] forced from host plants byLysiphlebus Testaceipes [Hym.; Braconidae]

Autor: R. W. McNew, W. E. Ruth, R. D. Eikenbary, D. W. Caves
Rok vydání: 1975
Předmět:
Zdroj: Entomophaga. 20:65-71
ISSN: 1573-8248
0013-8959
Popis: In a laboratory study 150 sorghum plants were infested with greenbugs,Schizaphis graminum (Rondani), of ages 1, 3, and 5 days in densities of 5, 10, and 20 aphids per plant. Seventy-five of these infested plants were exposed to mated femaleLysiphlebus testaceipes (Cresson), and the number of aphids leaving each plant in a 4-hr period was recorded. Of the 75 plants exposed to parasitoids, an average of 41.0% of the aphids left the plants, compared to 0.9% from the 75 control plants. Twenty-six of the 75 parasitoids used in the experiment were inactive in the presence of aphids, showing no interest in searching for hosts. The number of inactive parasitoids was inversely related to the number of aphids per plant. When only those plants exposed to active parasitoids were considered, an average of 62.8% of the aphids left. To determine the fate of greenbugs leaving plants on hot, sunny, summer days, a small field test was performed in which greenbugs were knocked from plants onto soil exposed to direct sunlight. Air temperature was ca. 29°C and soil temperatures ranged from 45°C to 54°C. Twenty-four greenbugs were knocked to the soil, and all of them ceased activity within 10 seconds and were apparently dead.
Databáze: OpenAIRE
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