A field experiment was conducted to investigate the population dynamics of phytophagous mites Tetranychus urticae Koch and Aculus lycopersici (Tryon) and their relation to prevailing weather variables on three Tomato cultivars 'Aliaa', 'Login' and 'Zena' in Shebeen El-Kom, Menoufia governorate, Egypt, during Summer and Nile seasons of 2021. The three tomato cultivars significantly differed in their susceptibility to T. urticae and A. lycopersici infestation. Login cultivar was the most highly significant susceptible to T. urticae and A. lycopersici infestation respectively 23.27 & 35.09, 24.50 and 28.88 individuals/ leaflet. In the summer season, T. urticae and A. lycopersici has one peak in mid-July of the three cultivars recorded 34.93, 44.23 and 30.83 individuals/ leaflet for T. urticae and 55. 37, 58.23 and 35.40 for individuals/ leaflet for A. lycopersici. While in Nile season the two mite pests have one peak in mid-November on Aliaa and Zena and in late October on the Login cultivar. Population dynamics of T. urticae and A. lycopersici on the three Tomato cultivars during the summer season were affected significantly positive correlation by temperature, while it has a nonsignificantly negative correlation with relative humidity. Results showed that changes in the host plant's nutritional content had a greater impact on the dynamics of the mite population than did changes in the weather. Statistical analysis indicated that highly significant positive correlation between the three predators and the two phytophagous mites T. urticae and A. lycopersici population on three Tomato cultivars. In conclusion, these results of the current study contribute to developing an effective plan for the IPM of phytophagous mites on tomatoes.

Developmental times, reproduction rate and life table parameters of Tetranychus urticae Koch of two ornaments plants Marshmallow and Salvia treated with four doses of gamma radiation 15, 25, 35 and 45 Kilo rad was studied under laboratory conditions at 25 ± 2°C, 65% RH. The results indicate that applied of gamma radiation had a significant effect on the duration of male and female feeding on salvia and Marshmallow leaves irrigated. The life cycle and generation period of irradiated females increased with increasing doses of gamma radiation and were significantly higher than the control. The female oviposition and longevity periods of T. urticae significantly increased with an increased dose of gamma radiation. The mean fecundity and daily rate significantly decreased with increasing doses of gamma radiation on salvia and marshmallows. A significant positive correlation was found between all immature stages, generation, and oviposition periods and the dose of gamma radiation. The Intrinsic rate of increase (r m) and net reproductive rate (R0) of T. urticae was the lowest at 45 Kilo rad (0.148 female/female/day and 20.59 female/female) and the highest value was found at control (0.256 female/female/day and 44.70 female/female), respectively on salvia leaves. The radiation of salvia and Marshmallow seeds reduced the fecundity of T. urticae females and prolonged the generation time than in control.