Duplication of acetylcholinesterase gene in diamondback moth strains with different sensitivities to acephate.

This study examined the acetylcholinesterase 1 gene (AChE1) in Plutella xylostella strains with different sensitivities to acephate. Multiple haplotypes of the gene were found in the field-collected strains including distinct haplotypes carrying one or both previously reported mutations (A298S and G324A). Moreover, sequencing results indicated the presence of duplicated copies of the gene in the field-collected strains.

Identification and expression of caspase-1 gene under heat stress in insecticide-susceptible and -resistant Plutella xylostella (Lepidoptera: Plutellidae).

A caspase gene in Plutella xylostella (DBM) was identified firstly and named Px-caspase-1. It had a full-length of 1172 bp and contained 900 bp open reading frame that encoded 300 amino acids with 33.6 kDa.

RNA interference-mediated knockdown of a cytochrome P450, CYP6BG1, from the diamondback moth, Plutella xylostella, reduces larval resistance to permethrin.

We have previously reported that a cytochrome P450, CYP6BG1, from Plutella xylostella was found to be overexpressed in 4th instars of a permethrin resistant strain and inducible in the susceptible counterpart. The findings suggested potential involvement of CYP6BG1 in permethrin resistance, hence warranted a functional analysis. To assess the functional link of the gene to permethrin resistance, we adopted RNA interference-mediated gene silencing (RNAi) by dsRNA droplet feeding.

Hydrolysis of acetylthiocholine iodide and reactivation of phoxim-inhibited acetylcholinesterase by pralidoxime chloride, obidoxime chloride and trimedoxime.

The hydrolysis of acetylthiocholine iodide (ATCh) by pralidoxime chloride (2-PAM Cl), trimedoxime (TMB(4)) and obidoxime chlpride (LUH(6)) was studied at pH 5.8-8.0 and incubation temperature from 5 to 40 degrees C in vitro.

Insecticide susceptibility of surviving Cotesia plutellae (Hym: Braconidae) and Diaeretiella rapae (M'Intosh) (Hym: Aphidiidae) as affected by sublethal insecticide dosages on host insects.

The effects of sublethal dosages of insecticides applied to Plutella xylostella L. (Lepidoptera: Yponomeutidae) and Lipaphis erysimi Kaltenbach (Homoptera: Aphidiidae) on the insecticide susceptibility of the surviving endoparasitoids, Cotesia plutellae Kurdjumov (Hymenoptera: Braconidae) and Diaeretiella rapae (M'Intosh) (Hymenoptera: Aphidiidae), were studied in Shangjie, Minhou, China. The susceptibility to methamidophos and the sensitivity of acetylcholinesterase (AChE) to methamidophos and dichlorvos in the adults of host insects were substantially lower than those in the two parasitoids.

Insecticide toxicity and synergism by enzyme inhibitors in 18 species of pest insect and natural enemies in crucifer vegetable crops.

The toxicities of three enzyme inhibitors and their synergistic effects on four insecticides were studied by using the dry film method on field populations of 18 species of insects collected in Jianxin and Shanjie, China, from 2003 to 2005. Meanwhile, the inhibitory effects of these enzyme inhibitors on the activities of acetylcholinesterases (AChE), carboxyesterases (CarE) and glutathione-S-transferases (GST), in vivo, were also studied. In general, triphenyl phosphate (TPP) and diethyl maleate (DEM) showed low toxicities to six herbivorous pest insects, four ladybirds and eight parasitoids.

Monooxygenase activity in methidathion resistant and susceptible populations of Amblyseius womersleyi (Acari: Phytoseiidae).

The purpose of this study was to evaluate the cytochrome P450-dependent monooxygenase activities in methidathion resistant and susceptible strains of Amblyseius womersleyi Schicha. Artificial laboratory selections for resistance and susceptibility to methidathion were performed in an organophosphate resistant strain of A. womersleyi (Kanaya strain).

Effects of synergists on toxicity of six insecticides in parasitoid Diaeretiella rapae (Hymenoptera: Aphidiidae).

The resistance to and the effects of synergists on the toxicity of six insecticides in Diaeretiella rapae (M'Intosh) (Hymenoptera: Aphidiidae), a parasitoid of vegetable aphid collected in Jianxin at Fuzhou-City, Fujian, China, were studied. In comparison with susceptible F21 progeny, the resistance ratios in resistant F0 parents were 27.6 for methamidophos, 20.

Seasonal changes of methamidophos susceptibility and biochemical properties in Plutella xylostella (Lepidoptera: Yponomeutidae) and its parasitoid Cotesia plutellae (Hymenoptera: Braconidae).

Methamidophos resistance and acetylcholinesterase (AChE) insensitivity to methamidophos, dichlorvos, and carbofuran were determined in the field populations of Plutella xylostella (L.) (Lepidoptera: Yponomeutidae) and its parasitoid Cotesia plutellae Kurdjumov (Hymenoptera: Braconidae) collected from the corresponding hosts between October 1998 and December 2003 in Fuzhou and Minhou, Fijian, China. Resistance levels to methamidophos and AChE insensitivity to the three insecticides in the two species of insects were high during autumn and spring and low during summer.

Molecular phylogeny of the Eichhorni group of Delias Hübner, 1819 (Lepidoptera: Pieridae).

The eichhorni group lies within the genus Delias (Lepidoptera: Pieridae) which has markedly diversified aposematic wing markings. The phylogenetic relationships among all species of the eichhorni group, representatives of each of the other 21 species groups of Delias butterflies, and some related genera were analyzed based on nucleotide sequences of the mitochondrial NADH dehydrogenase subunit 5 gene. A supplemental study using the nuclear elongation factor-1alpha (EF-1alpha) gene was also carried out.