Effects of plant probiotic bacteria and herbivore-induced plant volatiles on life table parameters of Tetranychus urticae (Acari: Tetranychidae) on kidney bean’s attached leaves

Abstract

ABSTRACT The two-spotted spider mite, Tetranychus urticae Koch (Acari: Tetranychidae), is an agricultural important polyphagous pest of many crops that causes significant yield loss. In this study, the effect of four herbivore-induced plant volatiles (HIPVs) (methyl jasmonate, methyl salicylate, indole, and 3-pentanol) with a concentration of 100 mmol/L and two plant probiotic bacteria (PBB) (Bacillus pumilus INR7 and Bacillus velezensis H3), were investigated on life table parameters of T. urticae under laboratory conditions (25 ± 1°C, 65 ± 5% RH, and 16 L: 8D). The T. urticae cohorts were reared on attached leaves of kidney bean plants (Phaseolus vulgaris L.) treated with HIPVs and PBBs, separately. The life history data were analysed using age-stage, two-sex life table theory. The intrinsic rate of increase (r) on methyl salicylate (0.1667 ± 0.0087 day-1) and B. velezensis treatment (0.1640 ± 0.0099 day-1) was significantly lower than the control group (0.1934 ± 0.0100 day-1). The finite rate of increase (λ) ranged from 1.178 ± 0.0116 day-1 on the B. velezensis to 1.2134 ± 0.0121 day-1 on the control with a significant difference (P < 0.05). The gross reproduction rate (GRR) on the indole treatment was significantly lower than the other treatments (28.14 ± 3.66 offspring). Based on the results, methyl salicylate, B. velezensis and indole could be considered resistance inducing materials against T. urticae.