Population fluctuation of cottonwhitefly, Bemisiatabaci (Gennadius) on certain tomato hybrids at Sohag region

The population trend of B. tabaci adults and nymphs on tomato crop in winter plantation in terms of weekly mean numbers/ 10 leaves during the study period (2018/2019 and 2019/2020 seasons), The adults of whitefly started to take place from the first week of inspection, then the population increased to form three peaks of activity in both seasons. However, for the nymphs, the population started to appear on tomato leaves in the second week of inspection in both seasons, then increased to form two and one peaks in the two seasons, respectively. Also, data showed that the susceptibility of seven tomato hybrids to infestation by B. tabaci adults and nymphs, respectively, during two successive seasons 2018/2019 and 2019/2020.For adults, Hybrid Lugen appeared as moderately resistant (MR) in both seasons, also, Hybrid Super red, Hybrid 102, Hybrid 449 showed Low resistance (LR) to B. tabaci, adults While, Hybrid 65010, Hybrid 83 and Hybrid 039 appeared as susceptible (S) in both seasons. Also, for nymphs, it is clear differences between the tested hybrids were significant during the two seasons. Hybrid Super red, Hybrid 102,HybridLugen and Hybrid 449 showed Low resistance (LR) to B. tabaci nymphs during the both seasons While, Hybrid 65010, and Hybrid 039 appeared as susceptible (S) in both seasons.