The work was conducted to clarify the efficiency of certain insecticides on the population of whitefly B. tabaci and incidence of yellow leaf curl virus (TYLCV) in tomato field. The experiment was carried out during Nili plantation of two successive seasons at El-Fayoum governorate. The obtained data showed that the alternate use of etofenprox /thiamethoxam; imidacloprid/ thiamethoxam; acetamiprid/ etofenprox; single continuous application of etofenprox; etofenprox / imidacloprid; acetamiprid/ imidacloprid; thiamethoxam/ acetamiprid; imidacloprid; thiamethoxam and acetamiprid gave excellent initial mortality over 90% on the adult stage of B. tabaci and incidence of tomato yellow leaf curl virus without significant differences between treatments. Thimethoxam as soil drench proved to be the most effective insecticide against adult and immature stages of whitefly, while acetamiprid achieved the lowest mortality for these two stages as well as short residual mortality. On the other hand, alternation of etofenprox / imidacloprid showed the highest initial mortality on nymphs. Residue levels in tomato fruits were also investigated at 30, 45 and 60 days after application of tested insecticides. For imidacloprid residues were found in amounts nearly above maximum residue levels MRLs 30 days while degraded to amounts below MRL by the progression of time to 45 and 60 days after application. Application of imidacloprid in alternate spray program with thiamethoxam; etofenprox; acetamiprid resulted in residues below MRL at the 3 preharvest intervals. Acetamiprid when used at the recommended rate showed the residue of 0.36 mg/kg at early season and then decreased to 0.08 mg/kg at late season. Alternate use of acetamiprid with thiamethoxam; etofenprox or imidacloprid reduce MRLs in tomato fruits. The successive applications of etofenprox alone at the recommended rate resulted in residues above MRL after 30 and 45 days and approximately near MRL at 60 days. On the other hand, the half rate in alternative use with imidacloprid; acetamiprid or thiamethoxam showed residues below MRL at all sampling intervals. Thiamethoxam when used in single successive applications gave residues of 2.5, 1.9 and 1.5 mg/kg at the 3 preharvest intervals, respectively

Field trials were conducted at El-Gharbia governorate to determine the insecticidal activities of chlorpyrifos-methyl, profenofos and methomyl on tomato plants against the cotton leaf-worm (Spodotera littoralis). Data showed the high initial mortality (100, 100 and 100%) against the second and the fourth instars larvae with reasonable persistence. The residues of these insecticides on fruits of the sprayed and contaminated tomato plants were determined by GLC and HPLC, with recoveries of 100, 100 and 94.58%, respectively. The initial deposits of chlorpyrifos-methyl, profenofos and methomyl were 2.10, 2.58 and 20.11ppm, while decreased to 0.19, 1.41 and 0.33ppm after 3,1 and 13 days from spraying, respectively, such residue levels are below the maximum residue level (MRL). The estimated half-life values (t0.5) were 0.4898, 1.026 and 1.1867 days for the same insecticides, respectively

A field experiment was conducted during autumn plantation in season 2017 at Qaha, Qalubiya Governorate to evaluate the efficiency of ten different control agents; four of them are biorational components (garlic extract, rosemary oil + sunflower oil, sesame oil and chili oil), three of them are natural pesticide (Techno Oil, Top9 and Berna Star), one agent of them is bio-pesticide (bio-fly) and two chemical pesticide (Blanch 48% SC, Mospilan 20% SP) in reducing the population densities of Bemisia tabaci and Tetranychus urticae on Hatma potato cultivar. The results indicated that there were significant differences between the ten tested compounds in reducing the population density of B. tabaci nymphs; Mospilan 20% SP was the most potent compounds in reducing the population density of B. tabaci nymphs causing the highest reduction percentage (83.58 %), while Top9 gave a low effect with reduction percentage (49.32%) and Bio-fly gave moderate reduction percentage (63.92%). These compounds could be divided into two groups according to the reduction percentage: 1st group contains Mospilan 20% SP, Blanch 48% SC (chemical pesticides), Berna Star and Techno Oil (natural pesticides), respectively. 2nd group contains on Bio-fly (bio-pesticide), sesame oil, garlic extract, chili oil, rosemary oil + sunflower oil (biorational components), and Top9 (natural pesticide) on B. tabaci nymphs. Results also revealed that there were significant differences between the mean of general reduction percentage of the ten tested compounds on T. urticae population. Mospilan 20% SP recorded the highest reduction percentage (73.1 %), (rosemary oil + sunflower oil) treatment recorded the lowest reduction percentage 41.97% and Top9 gave moderate reduction percentage (60.03%). These compounds could be divided into two groups: 1st group contains on Mospilan 20% SP, Techno Oil, Blanch 48% SC, garlic extract, Top9, chili oil, sesame oil and Berna Star respectively. 2nd group contains on Bio-fly and (rosemary oil + sunflower oil) respectively

Two experiments were carried out at the Central Laboratory for Agricultural Climate (CLAC), Agricultural Research Center and the Experimental Research Station attached to the Faculty of Agriculture, Ain shams Univ., Shalakan, Qalyubyia Governorate. The experiments were conducted for two summer seasons in 2015 and 2016 under unheated multi span plastic house and under open field conditions. Both experiments aimed at investigating the effect of certain weather conditions on the impact of three insecticides used for the control of the cotton whitefly, Bemisia tabaci (Gennadius) nymphs on four cucumber cultivars. The aims of the plastic house experiment and open field experiment were to investigate the impact of certain climatic conditions (Temperature (Co), Relative humidity (%) on different insecticides efficiencies used for whitefly control compared to untreated  check (without any insecticide application). Lex (Dinotefuran) insecticide was the more effect on the nymphs of B.tabaci inside the plastic house or in the open field followed by Oshin (Thiamethoxam) insecticide. However Bernastar was the lowest efficiency. Concerning effect of climatic conditions, air temperature and relative humidity affected the performance of the three tested insecticides especially during the days with temperature over 35°C.