Avermectin [KLH]

Greenhouse products are subject to contamination by pesticides used to control pests and diseases. Toxicity on human and non-target animals, destruction of environment, and bioaccumulation are just some of the problems caused by indiscriminate use of pesticides. Imidacloprid and abamectin are two widely used pesticides to control greenhouse pests in Varamin region (Tehran Province, Iran). The aim of this study was to determine the effect of some household operations including refrigerated storage (48 hours), immersion in water (5 hours) and combination of these two treatments on reduction of pesticide residues in two most freshly consumed vegetables, cucumber and tomato. Sampling was performed in three randomly selected greenhouses of each crop in Varamin. Pesticides residue were extracted from samples according to QuEChERS method and determined by High Performance Liquid Chromatography (HPLC) system equipped with UV detection and analytical column C18 (250x4.6 mm). Results showed that crops were contaminated more than maximum residue level of these pesticides. Although in most cases, refrigerated storage treatment reduced pesticides residue more than immersion in water, their combination was the most effective treatment. Based on the results, this treatment caused imidacloprid residues reduction of 91.3 and 60.2% and abamectin residues reduction of 81.4 and 70.3% in cucumber and tomato, respectively. These findings showed that some easy, accessible, and domestic solutions can dramatically reduce residues of these two common pesticides.

Twospotted spider mite (TSSM), Tetranychus urticae Koch, is an early season pest of cotton in the mid-southern USA and causes reduction in yield, fiber quality and impaired seed germination. Objectives of this study were to investigate the efficacy of abamectin and spiromesifen with two divergent LC50 values against TSSM in a computer-operated spray table which simulated aerial application parameters. Combined with a pressure of 276 kPa and a speed of 8 km/h, a 650033 nozzle delivered a spray rate of 18.7 L/ha. The active ingredient rates were 1/8, 1/4, 1/2 and the lowest label recommended rates for early season cotton. The intent was to study efficacy relative to deposition characteristics at active ingredient rates equal to and lower than those recommended by the label. Spectral reflectance values from a multispectral optical sensor were used to calculate the Normalized Difference Vegetation Index which numerically described the surface reflectance characteristics of cotton canopies concomitant to damage caused by T. urticae in the greenhouse. Water sensitive paper samplers described spray droplet spectra parameters (D-v0.1, D-v0.5 and D-v0.9, A mu m) and percent spray coverage. The volume median diameter (D-v0.5, A mu m) for abamectin and spiromesifen were respectively, 218 and 258 at one-half rate of the lowest label rate. These spray droplets were well above the driftable portions of the spray volume (< 141 A mu m) for both abamectin and spiromesifen. Efficacy evaluations indicated that spiromesifen was more effective than abamectin in controlling T. urticae on early season cotton at one-half rate of the lowest label rate. Results reported herein demonstrate that the multispectral optical sensor in lieu of manually counting T. urticae appears to be a promising tool for efficacy evaluations against acaricides for early season plants grown in greenhouses.