Resistant and susceptible populations of the diamondback moth (Plutella xylostella) were tested with crystalline, solubilized, and partially and fully activated forms of the Bacillus thuringiensis Cry1Ac delta-endotoxin. Fully activated toxin greatly reduced the resistance ratio (ratio of the 50% lethal concentration for the resistant population to that for the susceptible population) of the re...

Extremely hot events (usually involving a few hours at extreme high temperatures in summer) are expected to increase in frequency in temperate regions under global warming. The impact of these events is generally overlooked in insect population prediction, since they are unlikely to cause widespread mortality, however reproduction may be affected by them. In this study, we examined such stress ...

Studies were conducted in 1989 and 1990 at Lane, Oklahoma, to evaluate the economic benefits of managing lepidopterous pests of fresh-market cabbage using Bacillus thuringiensis Berliner var. kurstaki, or a pyrethroid insecticide in combination with an economic threshold based on larval density. Marketable cabbage yield and percent head damage were not significantly different among plots spraye...

Six to nine populations of the diamondback moth, Plutella xylostella (L.), were collected annually from fields of crucifer vegetables in the United States and Mexico from 2001 to 2004 for baseline susceptibility tests and resistance monitoring to spinosad, indoxacarb, and emamectin benzoate. A discriminating concentration for resistance monitoring to indoxacarb and emamectin benzoate was determ...

BACKGROUND Some plants hyperaccumulate the toxic element selenium (Se) to extreme levels, up to 1% of dry weight. The function of this intriguing phenomenon is obscure. RESULTS Here, we show that the Se in the hyperaccumulator prince's plume (Stanleya pinnata) protects it from caterpillar herbivory because of deterrence and toxicity. In its natural habitat, however, a newly discovered variety...

diamondback  moth,  piute/la xylostella  l. is  a  major pest of cruciferous  crops worldwide.   it  out broke in cabbage   fields  of tehran province   in  1999 and   caused considerable   yield   losses.  seven treatments  including  biological   and chemical   pesticides   were used in   the field  test.  these   treatments were as follow:  consult  (ec i 0%) 0.4 kg/h & 0.5 kg/h, carbaryle  ...

The levels of resistance to the insecticides cartap, deltamethrin and metamidophos were evaluated for three populations of the Diamondback Moth Plutella xylostella (L.) from the Federal District, Brazil in laboratory bioassays. The larvae of DBM showed levels of resistance to deltamethrin between 4 and 47 fold relative to a susceptible laboratory strain. The level of resistance to metamidophos ...

fermentation of 49 carbohydrates and oxidation and assimilation of 96 substrates were examined for ten beauveria bassiana isolates. principal component analysis indicated that there are significant differences among isolates for utilization of some substrates. esculine and d- glucose were positively fermented by all isolates. isolates were grouped into four clusters on the basis of hierarchial ...

The major pests of cabbage, Brassica oleracea var. capitata on Guam are diamondback moth, Plutella xylostella; cabbage webworm, Hellula undalis; cutworm, Spodoptera litura; cabbage cluster caterpillar, Crocidolomia pavonana; the fleahopper, Halticus tibialis and aphids. In the past, Chinese cabbage, Brassica chinensis cv. Tempest for C. pavonana; radish, Raphanus sativus cv. Minowase Summer Cro...