Two populations of Trichoplusia ni that had developed resistance to Bacillus thuringiensis sprays (Bt sprays) in commercial greenhouse vegetable production were tested for resistance to Bt cotton (BollGard II) plants expressing pyramided Cry1Ac and Cry2Ab. The T. ni colonies resistant to Bacillus thuringiensis serovar kurstaki formulations were not only resistant to the Bt toxin Cry1Ac, as prev...

Abstract Background Ephestia cautella (Walker) (Lepidoptera:Pyralidae) is one of the most economically important date fruits insect pests, which causes major losses in quantity and quality yield. The present study aimed to evaluate 3 entomopathogens: Beauveria bassiana (Basonym 1836), Metarhizium anisopliae (Metchnikoff 1879), Bacillus thuringiensis (Berliner 1915) var. kurstaki individually mi...

Bacillus thuringiensis var. israelensis (B.t.i.), HD-968-S-1983, and a primary powder of Bacillus sphaericus 2362 were assayed against Mansonia titillans and Ma. dyari. The susceptibility of the 2 species to the individual bacterial toxins was similar. The B.t.i. LC50 values were 50.5 micrograms/liter for Ma. dyari and 54.7 micrograms/liter for Ma. titillans; the B. sphaericus LC50 values were ...

Solubilized crystals of Bacillus thuringiensis var. israelensis were 7000 times less toxic to Aedes aegypti larvae than intact crystals, presumably because mosquito larvae are filter feeders and selectively concentrate particles while excluding water and soluble molecules. A procedure is described whereby soluble toxins are adsorbed to 0.8-micrometer latex beads, with retention of toxicity. The...

Leaf bioassays and oviposition choice tests were used to investigate the effects of transgenic broccoli expressing Cry1Ac toxin of Bacillus thuringiensis (Berliner) on susceptible and resistant Plutella xylostella (L.) larvae. Survival of susceptible 2nd instars on Cry1Ac-expressing broccoli declined from 99.1 to 19.2% at 24 and 72 h, respectively, and larvae exhibited an average weight loss of...

We tested toxins of Bacillus thuringiensis against larvae from susceptible, Cry1C-resistant, and Cry1A-resistant strains of diamondback moth (Plutella xylostella). The Cry1C-resistant strain, which was derived from a field population that had evolved resistance to B. thuringiensis subsp. kurstaki and B. thuringiensis subsp. aizawai, was selected repeatedly with Cry1C in the laboratory. The Cry1...

Pheromone traps can be used for evaluating the success of treatments that are applied to either eradicate or delay the growth of isolated low-density populations of the gypsy moth, Lymantria dispar (L.). We developed an index of treatment success, T, that measures the reduction in moth counts in the block treated adjusted by the change in moth counts in the reference area around it. This index ...