The effect of some fertilizer compounds as a resistance inducer in strawberry plants on life history parameters of Tetranychus urticae (Acari: Tetranychidae)

The two-spotted spider mite (TSSM), Tetranychus urticae Koch, is a major pest of strawberry crops and pest management strategies are essential to control it. Life table parameters are useful tools for evaluating resistance or susceptibility of host plants to pests. So, the effects of application of some fertilizer compounds on two strawberry cultivars (i.e. Festival and Fortuna), as a resistance inducer (i.e. fulvic acid, humic acid, potassium citrate, and calcium carbonate), have been investigated on biological characters and life table parameters of T. urticae under laboratory conditions. Results indicate that the oviposition period, adult longevity period and fecundity of T. urticae females were significantly affected when reared on leaf disks of two cultivars treated by above-mentioned fertilizer treatments. The number of deposited eggs per mite female also was remarkably different among the treatments and lower than that of the control. The fertilizer compounds significantly reduced the net reproductive rate (R0) and intrinsic rate of increase (r) compared to the control. Similarly, the finite rate of increase (λ) and gross reproduction rate (GRR) for the control were significantly higher than that of other treatments. The lower value of the intrinsic rate of increase (r) of T. urticae was recorded on Fortuna cultivar of strawberry plants treated by potassium citrate and calcium carbonate than that of other treatments. So, these compounds potassium citrate and calcium carbonate applied on could be relative resistance inducers for Fortuna cultivar of strawberry plants that decrease T. urticae populations. This suggests that these inducers with Fortuna cultivar could be employed toward a sustainable management of T. urticae.