Cultivating resistant host plants has been considered as an important strategy for sustainable pest management of mites. The current study was conducted to evaluate the response of 43 cucumber (Cucumis sativus L.) cultivars against two important tetranychid species, two-spotted spider mite (Tetranychus urticae Koch.) and strawberry spider mite (Tetranychus turkestani Ugarov & Nikolski). The experiment was implemented in a Randomized Complete Block design (RCB) with 43 treatments replicated 4 times in a greenhouse during 2015-2016. Two main evaluation criteria, cultivar injury rate (from 1 to 5) and number of eggs/female/day (EFD) on each cultivar, were used to compare responses. The results revealed that the highest number of eggs/female/day (EFD) for both mites was observed on Taha cultivar (9.0±0.40 and 9.5±0.28 for T. urticae and T. turkestani, respectively). The highest injury rate was also observed on this cultivar (4.8±0.26 and 5.0±0.0 for T. urticae and T. turkestani, respectively). In contrast, the lowest EFD number for T. urticae (2.8±0.47) and T. turkestani (2.5±0.28) was seen on Samer star and Davos cultivars, respectively. However, no host preference for egg-laying was observed on Iver and Samer star cultivars for T. turkestani. These two cultivars had the lowest injury level too (1.2±0.25 for Samer star and 1.5±0.28 for Negeen to T. urticae and T. turkestani, respectively). The obtained results demonstrated that Taha was the most susceptible cultivar colonized easily by both two tetranychid species. In contrast, Samer star and Negeen were the most resistant cultivars, strongly recommended for cultivation in greenhouses.
FUNCTIONAL RESPONSE OF THE COCCINELLID PREDATOR Stethorus gilvifrons MULSANT FEEDING ON THE TWO SPOTTED SPIDER MITE, Tetranychus urticae KOCH: THE EFFECT OF DIFFERENT PREY STAGES