The comparison of demographic traits in Tetranychus urticae Koch (Acari: Tetranychidae) on five different greenhouse cucumber hybrids (Cucumis sativus)

The two-spotted spider mite, Tetranychus urticae Koch is among the most serious crop pest around the world. Greenhouse crops are considered one of its most susceptible host plants. The aim of this study was to assess demographic traits (generation time, r(m), longevity, fertility and fecundity) of T. urticae on five different greenhouse cucumber cultivar hybrids (Negeen, 2502, 2526, Nasim and Green Magic). The study was taking place in laboratorial conditions, with 25 +/- 0.5 degrees C, RH = 65 +/- 5% and 16L:8D, in clip cages attached to the plants terminal leaves. Results showed that the longer generation time (11.18 +/- 0.12 days) and the shorter (9.28 +/- 0.14 days) was seen on Negeen and Green Magic respectively. The lowest r(m) value (0.254), fertility (41.33 +/- 6.5 eggs) and fecundity (30.00 +/- 4.74 females) were recorded on 2502, while, on Green magic, we recorded the highest r(m) value (0.313), fertility (49.60 +/- 9.27 eggs) and fecundity (36.53 +/- 6.97 females). The differences among results of each parameter were highly significant. According to the results of this study, 2502 was not a suitable host for population expanding in T. urticae and had some resistance level to this pest. But we could conclude about Green magic, as a partial susceptible cultivar that should be investigated as an important element in greenhouse cultivation systems.