The quality of the host plant affects the life history parameters of tetranychid mites. The biology and fertility life tables of Tetranychus merganser on five host plants (Carica papaya, Phaseolus vulgaris, Capsicum annuum var. glabriusculum, Helietta parvifolia, and Rosa hybrida) were assessed under laboratory conditions at 28 ± 1 °C and 70–80% relative humidity (RH) with a photoperiod of 12:12 h (L:D). The development period of immature females differed among the tested host plants and ranged from 9.32 days on P. vulgaris to 11.34 days on H. parvifolia. For immature males, it ranged from 9.25 days on P. vulgaris to 11.50 days on H. parvifolia. The female survival rate varied from 53.97% on H. parvifolia to 94.74% on P. vulgaris. The highest total fecundity rate was recorded on P. vulgaris (125.40 eggs/female) and the lowest on H. parvifolia (43.92 eggs/female). The intrinsic rate of increase (rm) varied from 0.271 (H. parvifolia) to 0.391 (P. vulgaris). The net reproductive rate (RO) was higher on P. vulgaris than on the other host plants. The longest mean generation time (GT) was calculated on C. annuum var. glabriusculum and the shortest on Rosa hybrida. The demographic parameters suggest the unsuitability of H. parvifolia as the host for the development of red spider mites, and the best performance of T. merganser was on P. vulgaris.

The aim of this study was to evaluate the effect of salicylic acid (SA) application on pre-transplant acclimatization of native populations of tomato. SA is a growth regulator that modifies plant growth and development by inducing changes in cell processes, physiology and morphology. Five populations of native tomato were sown in polystyrene trays. Peat moss was used as substrate and plants were maintained at field capacity continuously. After emergence, seedlings were applied during three weeks with different concentration of SA (0.0, 0.01, 0.1, 0.5 and 1.0 μM). A completely random experimental design was used with five replications per treatment. The growth parameters evaluated were height, stem diameter, number of leaves, hypocotyl length, shoot fresh and dry weight (leaves and stem), and root length and fresh and dry weight. An analysis of variance was carried out, and means were compared with the Tukey test (5%) using SAS statistical software. The recorded data show that pre-transplant seedlings of each of the evaluated populations responded significantly (P=0.01) to the SA treatments. Also, the comparison of means of each of the factors under study showed positive changes. With the concentrations of 0.5 and 0.1 μM SA, higher values of the studied variables were obtained than with the concentrations 0.01 and 1.0 μM SA. The native tomato populations sprayed with SA at concentrations of 0.5 and 0.1 μM responded positively in terms of seedling growth and development. Based on these findings, SA treatments can help acclimatize and present better growth conditions to the seedlings before being transplanted.