Field experiments were carried out in Egypt to investigate the infestation rates of cotton whitefly Bemisia tabaci on five cultivars of cucumbers Cucumis sativus during two consecutive late summer seasons from 11 August to 28 October 2015 and 2016. The susceptibilities of the cultivars to infestation by this pest were examined. The five cultivars – Hayl, Nems, Beit Alpha Zena, Bahi and Wafier – were cultivated on a private farm in Mansheyet Saqqara village, Giza. The results showed that whitefly infestation peaks were high in September and October, but low in November in both seasons. The population densities of Bemisia tabaci eggs, nymphs and adults on all the cultivars were slightly higher in 2015 than in 2016. Numbers of B. tabaci eggs, nymphs and adults rose with increasing the temperatures in both seasons, and mean numbers of nymphs and adults also increased with decreasing RH% on all the cultivars. The combination of temperature and humidity was an important regulatory factor affecting B. tabaci development. The results of this study showed that high infestation peaks of B. tabaci occurred in September and October of both seasons. The present results were used to classify the degrees of susceptibility of these cucumber cultivars to B. tabaci infestation as susceptible (S), low resistant (LR) and moderately resistant (MR). It is important that these degrees of susceptibility be referred to the degree of resistance of each cultivar to insect infestation.

Internal changes of temperature, moisture content and PH values of infested date palm trees with red palm weevil, Rhynchophorus ferrugineus were studied. The results indicated that internal Palm tree temperature at 6 am, Palm tree temperature at 12 pm and mean temperatures were increased in infested areas in infested trees during the different months. . Palm tree temperature at 6 am inside infested trees ranged between 12.8º C ( in January) and 34.8º C ( in August). The differences of Palm tree temperature at 6 am. between infested and healthy trees ranged between 0.1º C in January and 6.1º C in April. Palm tree temperature at 12pm in infested trees ranged from 11.9 ºC in January to 30 ºC in December and 7.8 ºC in October. Mean temp. in infested trees ranged between 12.4ºC in January and 32.4º C in August, while, the differences ranged between 2.2º C in January and 6.9 ºC in October.The moisture contents decreased in infested trees (ranged between 59.5 % in March and 78.3 % in November, while the differences ranged between 0.2 % in May and 9.6 % in March.PH values were lower inside infested areas than in healthy trees, where the range in infested trees fluctuated between 4.23 in May and 5.28 in March. The differences in PH ranged between 0.45 in March and 1.60 in June.