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It is well recognized that the quality of host plants affects the development and survival of twospotted spider mite Tetranychus urticae Koch. The life table parameters of T. urticae, on six cultivars of common bean (Phaseolus vulgaris L.) (chiti Khomein, chiti Ks21189, red Akhtar, red Ks31169, white Pak, and white G11867) were studied at constant laboratory conditions (27 +/- 2 degrees C, 70 +/- 5% RH and 16:8 L:D). Total development times of immature males and females were significantly influenced by bean cultivar. T. urticae laid significantly more eggs per day on red Akhtar (16.16) than on the other cultivars. The mean generation time ranged from 23.37 to 34.82 d, and a significant varietal effect was seen. Percentage of egg hatchability oftwospotted spider mite ranged from 88.25 to 94.20%. The highest intrinsic rate of increase, was recorded on red Akhtar (0.269 +/- 0.031) and the lowest value was obtained on white Pak (0.129 +/- 0.048). In addition, net reproductive rate and finite rate of increase of the twospotted spider mite had the highest value on red Akhtar: 62.38 +/- 1.05 and 1.30 +/- 1.02, respectively. The lowest values of these parameters were recorded on white Pak as 26.11 +/- 1.40 and 1.13 +/- 1.10, respectively. Doubling time varied significantly on different cultivars and the lowest and highest values were obtained on red Akhtar and white Pak, respectively. Our findings revealed that white beans (Pak and G11867) were less suitable cultivars, suggesting that they are more resistant to the twospotted spider mite than the other cultivars.

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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.