bifenthrin and bifenazate

Tetranychus urticae (Koch) is an economically important pest of many agricultural commodities world-wide. Multiple acaricides, including bifenazate, bifenthrin, and extoxazole, are currently registered to control T. urticae. However, populations of T. urticae in many different growing regions have developed acaricide resistance through multiple mechanisms. Within T. urticae, single nucleotide polymorphisms (SNPs) have been documented in different genes which are associated with acaricide resistance phenotypes. The detection of these mutations through TaqMan qPCR has been suggested as a practical, quick, and reliable tool to inform agricultural producers of acaricide resistance phenotypes present within their fields and have potential utility for making appropriate acaricide application and integrated pest management decisions. Within this investigation we examined the use of a TaqMan qPCR-based approach to determine genotypes which have been previously associated with acaricide resistance in field-collected populations of T. urticae from peppermint fields and hop yards in the Pacific Northwest of the United States and confirmed the results with a multiplex targeted sequencing. The results suggest that a TaqMan qPCR approach accurately genotypes T. urticae populations for SNPs that have been linked to Bifenazate, Bifenthrin, and Etoxazole resistance. The results also demonstrated that different populations of mites in Washington and Idaho displayed varying frequencies of the examined SNPs. While we were able to detect the SNPs associated with the examined acaricides, the mutation G126S was not an appropriate or accurate indicator for bifenazate resistance.

Topics: Acaricides; Animals; Mentha piperita; Polymorphism, Single Nucleotide; Tetranychidae; Washington

A rapid, sensitive, and effective multiresidue analytical method was established to investigate the degradation rate and final residues of bifenthrin, bifenazate, and its metabolite bifenazate-diazene in apples, and the dietary risk of consumers was evaluated. The residues of bifenthrin, bifenazate, and bifenazate-diazene in apple samples from 12 different apple-producing areas of China were determined by high-performance liquid chromatography tandem mass spectrometry (LC-MS/MS). The average recoveries of the three compounds in apples were 88.4-104.6%, and the relative standard deviations (RSDs) were 1.3-10.5%. The limit of quantification (LOQ) for each compound was 0.01 mg/kg. Although the degradation half-lives of bifenthrin, bifenazate, and bifenazate-diazene were 17.8-28.9, 4.3-7.8, and 5.0-5.8 days, under good agricultural practice (GAP) conditions, the final residues of bifenthrin, bifenazate, and the sum of bifenazate and its metabolite bifenazate-diazene in apples were <0.01-0.049, < 0.01-0.027, and <0.02-0.056 mg/kg, respectively, which were lower than the maximum residue limit (MRL) in China. By comparing the deterministic model with the probabilistic model, the results of the probabilistic model at the P95 level (12.91-48.9% for bifenthrin, 17.48-52.01% for bifenazate including its metabolite) were selected as reasonable assessment criteria for chronic dietary risk, and the acute risk was at the P99.9 level (3.00-15.59% for bifenthrin). Although the exposure risk calculated by both the deterministic model and the probabilistic model was less than 100%, the risk to children is significantly higher than that of the general population. This suggests that in future research and policy making, we should pay more attention to the risk of vulnerable groups such as children.

Topics: Carbamates; Child; China; Chromatography, Liquid; Half-Life; Humans; Hydrazines; Imides; Malus; Pesticide Residues; Pyrethrins; Risk Assessment; Tandem Mass Spectrometry

Tetranychus urticae (T. urticae) Koch is an important pest of vegetable crops worldwide. In this study, bioassays were carried out to analyze the resistance risk, multi-resistance and management of T. urticae Koch to bifenthrin, bifenazate and cyflumetofen on cowpea.. The resistance ratios of the adult T. urticae population to bifenthrin (G16), bifenazate (G12) and cyflumetofen (G12) were 31.29, 9.38 and 5.81, respectively. Realized heritability (h. These results demonstrated the T. urticae developed higher resistance risk to bifenthrin compared to bifenazate and cyflumetofen and no obvious multi-resistance among these three acaricides, providing guidance for designing appropriate strategies for the effective application of bifenthrin, bifenazate and cyflumetofen in the field and delaying the development of insecticide resistance. © 2019 Society of Chemical Industry.

Topics: Acaricides; Animals; Carbamates; Hydrazines; Propionates; Pyrethrins; Risk Assessment; Tetranychidae; Vigna