spiromesifen and spirodiclofen

A fast, sensitive, and reliable analytical method was developed and validated for simultaneous identification and quantification of spirodiclofen, spiromesifen, and spirotetramat and their relevant metabolites in edible fungi by ultra-performance liquid chromatography/tandem mass spectrometry (UHPLC-MS/MS). First, sample extraction was done with acetonitrile containing 1% formic acid followed by phase separation with the addition of MgSO

Topics: 4-Butyrolactone; Acaricides; Agaricales; Aza Compounds; China; Chromatography, High Pressure Liquid; Food Contamination; Fungi; Limit of Detection; Spiro Compounds; Tandem Mass Spectrometry

Topics: 4-Butyrolactone; Acaricides; Animals; Aza Compounds; Dose-Response Relationship, Drug; Embryo, Nonmammalian; Fatty Acid-Binding Proteins; Lipid Metabolism; Pyrrolidinones; Spiro Compounds; Toxicity Tests; Water Pollutants, Chemical; Zebrafish; Zebrafish Proteins

Phytophagous mites such as the European red mite, Panonychus ulmi (Koch), are serious pests in European fruit tree orchards, and a number of acaricides are frequently used to control them. Spirodiclofen (Envidor(®)) has been a commonly used acaricide for several years. In the present study, European field populations collected in 2009 and 2010 were checked for their susceptibility to spirodiclofen by using discriminating dose and full dose response bioassays.. In 2009 and 2010, a total of 63 field populations (including winter eggs) of European red mites were collected in different European countries, and in several populations from south-western Germany a shifting in susceptibility against spirodiclofen was observed. Full dose response bioassays on different developmental stages of field-collected strains suggested an age-dependent expression of resistance because eggs remain fully susceptible to spirodiclofen. Artificial selection with spirodiclofen of one of the field strains resulted in resistance ratios of > 7000. Synergism studies suggest a possible role of cytochrome-P450-dependent monooxygenases in spirodiclofen detoxification. Most of the other acaricides from different chemical classes displayed no or low cross-resistance in a spirodiclofen-selected strain.. In order to preserve spirodiclofen as an important tool in spider mite resistance management, the efficacy situation should be continuously monitored, and it is suggested that spirodiclofen be alternated with acaricides coming from different mode-of-action classes. An observed age-specific expression of resistance revealed full susceptibility of eggs, so targeting spirodiclofen particularly against eggs is likely to reduce the selection pressures imposed on other life stages.

Topics: 4-Butyrolactone; Acaricides; Animals; Drug Resistance, Multiple; Female; Pesticide Synergists; Selection, Genetic; Spiro Compounds; Tetranychidae; Toxicity Tests

Spirodiclofen is a selective, non-systemic acaricide from the new chemical class of tetronic acid derivatives. In order to develop strategies to minimise resistance in the field, a laboratory-selected spirodiclofen-resistant strain of the two-spotted spider mite, Tetranychus urticae Koch, was used to determine genetic, toxicological, biochemical and cross-resistance data.. Selecting for spirodiclofen resistance in the laboratory yielded a strain (SR-VP) with a resistance ratio of 274, determined on the larval stage. The egg stage remained far more susceptible. No cross-resistance was found against other established acaricides, except for spiromesifen. Based on synergist experiments and enzyme assays, it appeared that especially P450 monooxygenases, but also esterases and glutathione-S-transferases, could be involved in the metabolic detoxification of spirodiclofen. Genetic analysis showed that the resistance is inherited as an intermediate trait under control of more than one gene.. Resistance to spirodiclofen exceeded by far the recommended field rate. A good acaricide resistance management programme is necessary to prevent fast resistance build-up in the field. Spirodiclofen can be used in alternation with most established acaricides, except for other tetronic acid derivatives. Without selection pressure, resistance tends to be unstable and can decrease in the presence of susceptible individuals owing to the intermediate, polygenic inheritance mode.

Topics: 4-Butyrolactone; Animals; Insecticide Resistance; Insecticides; Selection, Genetic; Spiro Compounds; Tetranychidae