Effects of six greenhouse cucumber cultivars on reproductive performance and life expectancy of Tetranychus turkestani (Acari: Tetranychidae)

Abstract

The strawberry spider mite Tetranychus turkestani Ugarov & Nikolskii is an important pest of greenhouse cucumber. Reproductive parameters, life expectancy and life table entropy of this mite on six greenhouse cucumber cultivars (Puia, Hedieh, Milad Jadid, Milad Ghadim, Khasib and Negin) were evaluated. These parameters were estimated by a leaf disc bioassay with six treatments and 40 replications under laboratory conditions (Tempt. 28 +/- 1 °C, RH: 60 +/- 5%, L:D = 16:8 h) in a walk-in growth chamber. The results of this study show that the highest total fecundity of the strawberry spider mite was observed on the Hedieh cultivar (29.784 egg/ female) and the lowest on the Puia cultivar (15.773 egg/ female). The highest gross and net fecundity rates of this pest were seen on the Hedieh cultivar (91.721 and 41.171 egg/female) and the lowest on the Puia cultivar (35.765 and 9.154 egg/female, respectively). The strawberry spider mite had the highest gross and net fertility rates on the Hedieh cultivar (44.913 and 26.720 egg/ female, respectively). Moreover, T. turkestani gross hatching rate on the six cucumber cultivars differed significantly, varying from 0.18 on Negin to 0.48 on Hedieh. The life expectancy of one-day-old adults of the strawberry spider mite was estimated to be 6.140, 7.800, 5.733, 6.551, 6.543 and 6.822 days on the above-mentioned cultivars, respectively. The values of the entropy parameter (H) of the strawberry spider mite on the cultivars were 6.600, 1.177, 8.468, 2.300, 1.249 and 0.247, respectively. These results suggest that Puia, Milad Jadid, Milad Ghadim, Khasib and Negin cultivars may have the highest resistance levels to this mite compared to the Hedieh cultivar. The use of resistant host plants is one of the most important components of an integrated pest management program.