Microbial biorationals as an effective alternative to pesticides for control of two spotted spider mite, Tetranychus urticae Koch (Acari: Tetranychidae) on parthenocarpic cucumber grown under protected conditions

Abstract

The use of chemical pesticides to control two spotted spider mite (TSSM), Tetranychus urticae Koch (Acari: Tetranychidae) in various crops has resulted in the development of various problems viz., residues in sprayed crop, pest resistance, pest resurgence and environmental pollution. For an effective alternate environmentally safe management tactic, the microbial biorationals constitute an important tool. In the present study, entomopathogenic fungi (EPF) and botanical pesticides were tested at different concentrations for the management of eggs and other active stages of T. urticae infesting parthenocarpic cucumber grown under poly-net house. Among these biorationals, spraying of Neem Baan at 10 and 15 ml/l resulted in significantly higher level of reduction in TSSM population (88.5 to 91.8% in egg and 86.6 to 90.9% in active stage of mites after 3rd spray, respectively) than with EPFs. Among the EPFs, Lecanicillium lecanii (Zimmerman) Viegas and Beauveria bassiana Balsamo (Vuillemin) [(at 10 & 15 ml/l (82.0 to 87.0% in egg and 79.2 to 84.1% in active stage of mites)] was found to be more effective than Metarhizium anisopliae (Metschnikoff) Sorokin [(at 10 & 15 ml/l (77.0 to 82.4% in egg and 76.4 to 80.4% in active stage of mites after third spray, respectively)] in reducing different life stages of T. urticae on cucumber. Significantly higher yields of cucumber were recorded from plot treated with Neem Baan at 10 and 15 ml/l (2350.7 to 2437.3 g/ plant) were used. As Neem Baan 1% increased growth and yield of cucumber by controlling T. urticae, effectively, it can act as a good alternative for the chemical pesticide which in most instances leads to residues, pest resistance and pest resurgence problems.