Bacillus thuringiensis Alone and in Mixtures with Chemical Insecticides against Heliothines and Effects on Predator Densities in Cotton

Young, S. Y.; Kring, T. J.; Johnson, D. R.; Klein, C. D.

doi:10.18474/0749-8004-32.2.183

Cited by 6 publications

(2 citation statements)

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“…Also, the doses used in the Bt spray studies are difficult to compare with doses of toxins in Bt plants. In studies with Bt sprays, the doses used may be expressed in kg ha −1 (varying from 0.68 kg ha −1 (Young et al ., 1997) to 2.3 kg ha −1 (Riddick and Mills, 1995)), in international toxicity units mg −1 water (e.g. Giroux et al ., 1994; Painter et al ., 1996), or in mg Bt toxin g −1 diet (e.g.…”

Section: Effects Of Toxins In Bt Plants On Biological Control Agentsmentioning

confidence: 99%

Insect‐resistant transgenic plants in a multi‐trophic context

Groot¹,

Dicke²

2002

The Plant Journal

172

100

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Summary So far, genetic engineering of plants in the context of insect pest control has involved insertion of genes that code for toxins, and may be characterized as the incorporation of biopesticides into classical plant breeding. In the context of pesticide usage in pest control, natural enemies of herbivores have received increasing attention, because carnivorous arthropods are an important component of insect pest control. However, in plant breeding programmes, natural enemies of herbivores have largely been ignored, although there are many examples that show that plant breeding affects the effectiveness of biological control. Negative influences of modified plant characteristics on carnivorous arthropods may induce population growth of new, even more harmful pest species that had no pest status prior to the pesticide treatment. Sustainable pest management will only be possible when negative effects on non‐target, beneficial arthropods are minimized. In this review, we summarize the effects of insect‐resistant crops and insect‐resistant transgenic crops, especially Bt crops, from a food web perspective. As food web components, we distinguish target herbivores, non‐target herbivores, pollinators, parasitoids and predators. Below‐ground organisms such as Collembola, nematodes and earthworms should also be included in risk assessment studies, but have received little attention. The toxins produced in Bt plants retain their toxicity when bound to the soil, so accumulation of these toxins is likely to occur. Earthworms ingest the bound toxins but are not affected by them. However, earthworms may function as intermediaries through which the toxins are passed on to other trophic levels. In studies where effects of insect‐resistant (Bt) plants on natural enemies were considered, positive, negative and no effects have been found. So far, most studies have concentrated on natural enemies of target herbivores. However, Bt toxins are structurally rearranged when they bind to midgut receptors, so that they are likely to lose their toxicity inside target herbivores. What happens to the toxins in non‐target herbivores, and whether these herbivores may act as intermediaries through which the toxins may be passed on to the natural enemies, remains to be studied.

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Section: Effects Of Toxins In Bt Plants On Biological Control Agentsmentioning

confidence: 99%

Insect‐resistant transgenic plants in a multi‐trophic context

Groot¹,

Dicke²

2002

The Plant Journal

172

100

View full text Add to dashboard Cite

show abstract

“…Numerous researchers have evaluated insecticide effects on beneficial arthropods by making evaluations in the field from treated field plots (Brown & Shanks 1976;Stoltz & Stern 1978;Young et al 1997;Simmons & Jackson 2000). Generally, the results from field studies express toxicity as the resulting presence or absence of the insect from a treated plot in comparison with an untreated plot or with pretreatment counts.…”

mentioning

confidence: 99%