Environmental Entomology (1990) 19, 428-431

Leah S. Bauer (1990)
Response of the cottonwood leaf beetle (Coleoptera: Chrysomelidae) to Bacillus thuringiensis var. san diego
Environmental Entomology 19 (2), 428-431
Abstract: A standardized laboratory bioassay was used to quantify the lethal and sublethal responses of larval and adult cottonwood leaf beetles, Chrysomela scripta F., to Bacillus thuringiensis var. sandiego, formulated as M-One standard powder (Mycogen Corporation, San Diego). The median lethal concentration (LC₅₀) for second instars, after a 96-h exposure to B. thuringiensis var. sandiego, was 21,000 Colorado potato beetle international units per milliliter water. The LC₅₀ estimates for the third instars and adults were 20 and 40 times higher than for second instars, respectively. Larval LC₅₀ estimates were halved when mortality for the entire larval period was included in the LC₅₀ estimate. Adult mortality continued for approximately 14 d after initial exposure to B. thuringiensis var. sandiego. The adult LC₅₀ calculated at 14 d was half the 4-d estimate. Age of adults at treatment did not significantly affect the LC₅₀ Median lethal times (LT₅₀) were similar for larvae and adults, with overlapping confidence limits ranging from 2.1 to 3.5 d. Larvae surviving treatments as second and third instars showed a significant dose-dependent decrease in adult dry weight at eclosion and an increase in the larval developmental period.
(The abstract is excluded from the Creative Commons licence and has been copied with permission by the publisher.)

Research topic(s) for pests/diseases/weeds:
biocontrol - natural enemies
Research topic(s) for beneficials or antagonists:
general biology - morphology - evolution

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Pest and/or beneficial records:

Beneficial	Pest/Disease/Weed	Crop/Product	Country	Quarant.
	Chrysomela scripta
Bacillus thuringiensis var. sandiego (entomopathogen)	Chrysomela scripta