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...

A pyrethroid-resistant strain of the diamondback moth, Plutella xylostella (L.), originally collected in Thailand showed cross-resistance to all the pyrethroids tested. Upon further selection with fenvalerate in the laboratory, the strain exhibited an extremely high LD50 value, 41 μg/larva, for fenvalerate. In genetic studies of the resistance, the F1 progeny showed recessive gene(s), while the...

Larval survival and oviposition behavior of three genotypes of diamondback moth, Plutella xylostella L. (Lepidoptera: Plutellidae), (homozygous Cry1Ac-susceptibile, Cry1Ac-resistant, and their F1 hybrids), on transgenic Bacillus thuringiensis (Bt) broccoli expressing different levels of Cry1Ac protein were evaluated in laboratory. These Bt broccoli lines were designated as relative low, medium,...

Resistance to diamondback moth, Plutella xylostella (L.), has been a major criterion for selection in the crucifer breeding program at the New York State Agricultural Experiment Station. Two types of resistance have been identified and studied. Larval survival on normal wax genotypes (with the typical whitish bloom of cultivated Brassica) is about 50% of survival on susceptibles. Polar extracts...

The induction of plant defenses by insect feeding is regulated via multiple signaling cascades. One of them, ethylene signaling, increases susceptibility of Arabidopsis to the generalist herbivore Egyptian cotton worm (Spodoptera littoralis; Lepidoptera: Noctuidae). The hookless1 mutation, which affects a downstream component of ethylene signaling, conferred resistance to Egyptian cotton worm a...

We studied the effects of combinations of Bacillus thuringiensis spores and toxins on the mortality of diamondback moth (Plutella xylostella) larvae in leaf residue bioassays. Spores of B. thuringiensis subsp. kurstaki increased the toxicity of crystals of B. thuringiensis subsp. kurstaki to both resistant and susceptible larvae. For B. thuringiensis subsp. kurstaki, resistance ratios were 1,20...

The widespread fungal pathogen Zoophthora radicans kills both adult and larval stages of the diamondback moth. At IACR-Rothamsted, a novel strategy for diamondback moth control, based upon a fast entry/ slow exit trap containing the female sex pheromone and the pathogen, is under development. Male moths are attracted into an inoculation chamber where they are showered with infective conidia of ...

Diamondback moth, Plutella xylostella (L.) (Lepidoptera: Plutellidae), has become the most destructive insect pest of cruciferous vegetables (Brassica oleracea L.) worldwide, and is a continuing problem especially in the southern United States. Because of inconsistencies in individual control methods, inefficiencies and time demands of scouting, and the lack of clear thresholds, current managem...

The present research represents the first investigations into the development of crosstolerance in the larvae of Diamondback Moth (DBM) tolerant to Bacillus thuringiensis toxin (Bt-toxin: Dipel) and treated with different concentrations of the entomopathogenic fungus Beauveria bassiana (strain BbGHA). Significant differences (at P = 0.05) were obtained between the fungus concentrations used for...

The entomopathogenic fungus Metarhizium anisopliae MA05-169 is a transformant strain that has been metabolically engineered to express dihydroxynaphthalene-melanin biosynthesis genes. In contrast to the wild type strain, the transformant displays a greater resistance to environmental stress and a higher virulence toward target insect host. However, the underlying mechanisms for these characteri...