Bioefficacy and persistence of acaricides applied against two spotted spider mite (Tetranychus urticae Koch) in cucumber (Cucumis sativus Linnaeus) under protected cultivation system

The two-spotted spider mite (Tetranychus urticae Koch ) is the most pronounced polyphagous non-insect pest, wreaking havoc on agricultural and horticultural crops. In cucumber, the infestation by various pests jeopardises effective cultivation, with two spotted spider mites causing great harm to the crop. Six different chemical acaricides were tested for their effectiveness against T. urticae in cucumber cultivated under protected cultivation system at the farmer’s field. The results revealed that none of the acaricides exhibited a tangible decrease over the control, but spiromesifen (59.50 %) recorded a rather excellent reduction over the other investigated chemicals (40 to 54.47 %). The experimental bioassays were performed to determine the effective dosage, which resulted in a significant mite population reduction and the results revealed that tested chemical acaricides were found to be effective at their higher dose, ranging nearly from 3X to 4X of recommended by CIB&RC. The pot culture and field study was conducted to determine the effectiveness of fixed doses from bioassay investigations. A good reduction in mite population was observed for all tested chemicals with spiromesifen recorded a 100 per cent reduction in mite population. Residue analysis of harvest time samples of cucumber after spiromesifen application revealed residues below quantification limit of 0.025 µg/kg.