اثرات میزبان‌های مختلف گیاهی بر پارامترهای شکارگری کنه‌ی شکارگر Typhlodromus bagdasarjani (Acari: Phytoseiidae)

The two-spotted spider mite, Tetranychus urticae Koch, is one of the most important phytophagous pests which cause severe damage to agricultural products worldwide. Application of natural enemies to suppress population density of this pest has incredible role in reducing chemical pesticides usage in different agro-ecosystems. The predatory mite Typhlodromus bagdasarjani Wainstein & Arutunjan is one the most important natural enemies of this pest worldwide and its feeding activity on different life stages of T. urticae could be considered in management programs of this mite pest. Since quality of host plants consumed by phytophagous pests could affect the biological performance of their natural enemies (bottom-up effects), in the present study, effect of four different greenhouse host plants including cucumber (cultivar Negin), tomato (cultivar Isabella), eggplant (cultivar Bell) and watermelon (cultivar Crimson) on the predation parameters of T. bagdasarjani were investigated. Experiments was performed under laboratory conditions at 25 ± 1 ºC, relative humidity of 65 ± 5 % and a light period of 16 h. Data analysis was performed using Age-Stage, Two Sex Consumption Rate theory. The results obtained revealed that the value of net predation rate (C0) was significantly different on different host plants tested. Accordingly, the highest value of this parameter was recorded on tomato (95.87 ± 12.88 prey) and the lowest value was recorded on eggplant (35.12 ± 4.88 prey). The calculated values of this parameter on cucumber and watermelon were 91.52 ± 13.58 and 56.99 ± 7.54 (prey), respectively. The highest value of transformation rate from prey population to predator offspring (Qp) was obtained on eggplant (16.43 ± 8.47 prey/predator offspring) and the lowest value was on cucumber (12.76 ± 2.60 prey/predator offspring). Furthermore, different hosts tested affected stable predation rate (ψ) of predatory mite T. bagdasarjani and the recorded values of this parameter on the above-mentioned host plants were calculated as 2.49 ± 0.19, 2.37 ± 0.15, 1.96 ± 0.12 and 1.93 ± 0.11 (prey/ predator), respectively. The values of finite predation rate (ω) was also affected by different host plants and the highest (2.73 ± 0.24 day-1) and lowest (2.03 ± 0.15 day-1) value of this parameter was obtained on cucumber and eggplant, respectively. The values of this parameter on tomato and watermelon were estimated as 2.61 ± 0.18 and 2.04 ± 0.14 (day-1), respectively. Our findings confirmed significant effects of different host plants on predation parameters of T. bagdasarjani. However, more attention should be devoted to evaluate biological performance of this predatory mite in integrated management of T. urticae on different host plants.