POPULATION GROWTH PARAMETERS OF THE TWO-SPOTTED SPIDER MITE, TETRANYCHUS URTICAE KOCH (ACARI: TETRANYCHIDAE) ON THREE STRAWBERRY VARIETIES

Abstract

The two-spotted spider mite, Tetranychus urticae Koch, is one of the most important pests of strawberry crops in world wide. The use of comparatively resistant cultivars or varieties may limit the negative effects of this mite. The present studies were compared to the population growth parameters of T. urticae reared on three strawberry varieties viz. RU-1, RU-2 and RU-3. The life table parameters were estimated under laboratory conditions (25 ± 2 0C, 60 ± 10% RH, and a photoperiod of 13:11 h L: D). The average developmental time in days from egg to female adult on the three varieties were 11.70 ± 1.23 (RU-1), 12.60 ± 0.91 (RU-2) and 12.77 ± 0.92 (RU-3), respectively. The lifetime fecundities were 57.38 ± 3.67, 56.57 ± 4.42 and 63.90 ± 4.33 eggs/female for RU-1, RU2 and RU-3, respectively. RU-2 was the most suitable host for T. urticae with rm = 0.172 (offspring/female/day), followed by RU-3 (0.170). The slowest population growth was observed on the RU-1 variety with rm = 0.167. The present findings revealed that RU-1 was less suitable variety, suggesting that if is more registrant to the two-spotted spider mite compared to the other two varieties.