Transgenic crops that express insecticide genes from Bacillus thuringiensis (Bt) are used worldwide against moth and beetle pests. Because these engineered plants can kill over 95% of susceptible larvae, they can rapidly select for resistance. Here, we use a model for a pyramid two-toxin Bt crop to explore the consequences of spatio-temporal variation in the area of Bt crop and non-Bt refuge ha...

Transgenic rice containing insecticidal protein(s) from Bt (Bacillus thuringiensis) effectively control lepidopteran pests under laboratory and field conditions. However, Bt rice has not been widely commercialized. A major concern regarding the deployment of Bt rice is its potential impact on non-target arthropods, including herbivorous insect pests and biological control agents (predators and ...

The refuge strategy can delay resistance of insect pests to transgenic maize producing toxins from Bacillus thuringiensis (Bt). This is important for the western corn rootworm, Diabrotica virgifera virgifera LeConte (Coleoptera: Chrysomelidae), because of its history of adaptation to several management practices. A 2-yr study across four locations was conducted to measure the effects of integra...

Strains of Bacillus thuringiensis (Bt) are known to produce crystalline proteins (δ-endotoxins) concomitantly with sporulation during their stationary phase of growth, which are demonstrated as lethal to lepidopeterous, coleopeterous and dipterous insects in addition to mites, nematodes, protozoa and flukes. Upon ingestion, the δ-nascent endotoxin is an inactive protoxin complex of (Cry alone o...

BACKGROUND Bacillum thuringiensis (Bt) toxin produced in Cry1-expressing genetically modified rice (Bt rice) is highly effective to control lepidopteran pests, which reduces the needs for synthetic insecticides. Non-target organisms can be exposed to Bt toxins through direct feeding or trophic interactions in the field. The wolf spider Pardosa pseudoannulata, one of the dominant predators in So...

Decreased larval feeding and weight of the monarch butterfly, Danaus plexippus L., have been detected after 4 d of exposure in the laboratory to a high density of Bacillus thuringiensis (Bt)-expressing anthers. One hypothesis is that larvae exposed to Bt anthers exhibit increased wandering, resulting in less feeding and lower weight gain. To test this hypothesis, 2-d-old monarch butterfly larva...

To compare, in a retrospective study, biochemical failure-free survival (bFFS) and overall survival (OS) in low-risk and intermediate-risk prostate cancer patients who received brachytherapy (BT) (either low-dose-rate brachytherapy [LDR-BT] or high-dose-rate brachytherapy with external beam radiation therapy [HDR-BT+EBRT]) versus external beam radiation therapy (EBRT) alone. Patient data were o...

53 The microbial insecticide, Bacillus thuringiensis (Bt), has become the mainstay of non-chemical control of 54 Lepidopteran pests, either as sprays or through the incorporation of Bt toxins into transgenic crops. Given 55 the wide use of Bt, it is striking that currently only one pest species, Plutella xylostella, has been reported 56 to have developed significant resistance to Bt outside the...

The sustainable deployment of resistant crop varieties is a critical issue for the implementation of biotechnology in crop pest management. Feeding, biomass accumulation, and mortality were evaluated for susceptible, insecticide-resistant, and Bacillus thuringiensis (Bt) Cry 3A-selected Colorado potato beetle ( Leptinotarsa decemlineata Say) (Coleoptera, Chrysomelidae) larvae fed on: cultivated...