Non-target impacts of forest defoliator management options: Decision for no spraying may have worse impacts on non-target Lepidoptera than Bacillus thuringiensis insecticides

Published source details Scriber J.M. (2004) Non-target impacts of forest defoliator management options: Decision for no spraying may have worse impacts on non-target Lepidoptera than Bacillus thuringiensis insecticides. Journal of Insect Conservation, 8, 241-261.
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This study is summarised as evidence for the following.

	Action	Category
	Use genetically modified crops which produce pesticide to replace conventional pesticide application Action Link

Use genetically modified crops which produce pesticide to replace conventional pesticide application

A controlled study (year not specified) in a laboratory (location not specified) (Scriber 2004) found that pollen from genetically modified maize expressing the Bacillus thuringiensis var. kurstaki (Btk) toxin against European corn borer Ostrinia nubilalis did not reduce the growth and survival of eastern tiger swallowtail Papilio glaucus or spicebush swallowtail P. troilus caterpillars more than pollen from non-genetically modified maize. The growth and survival of both eastern tiger swallowtail and spicebush swallowtail caterpillars exposed to a large quantity of genetically modified pollen (eastern tiger, survival: 83%, growth: 0.15 mg/mg/day; spicebush, survival: 81%, growth: 0.15) were similar to those exposed to the same quantity of non-genetically modified pollen (eastern tiger, survival: 88%, growth: 0.15 mg/mg/day; spicebush, survival: 83%, growth: 0.14 mg/mg/day), but both were lower than caterpillars which were not exposed to any maize pollen (eastern tiger, survival: 100%, growth: 0.30 mg/mg/day; spicebush, survival: 100%, growth: 0.30 mg/mg/day). The growth rates of caterpillars exposed to smaller quantities of genetically modified or non-genetically modified pollen were similar to those exposed to large quantities (data not presented). Forty-two eastern tiger swallowtail and 28 spicebush swallowtail caterpillars were fed tulip tree Liriodendron tulipfera or spicebush Lindera benzoin leaves dusted with either genetically modified or non-genetically modified maize pollen, at both 1% and 10% fresh leaf weight, or with no pollen dusting. Survival and growth rate were measured after 48 hours.

(Summarised by: Andrew Bladon)