Experiments were conducted on cucumber plants under greenhouse conditions (Barracuda cultivar) at Armant district, Luxor Governorate, Egypt, throughout two successive growing seasons (2021 and 2022) to study the population dynamics of the whitefly, Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae). The effect of temperature, relative humidity, and plant development on the oscillations of B. tabaci was studied. The results cleared that the number of B. tabaci individuals was detected on cucumber plants during the period from January 23^rd till April 17^th, i.e., the insect infestations appeared on plants that were eight weeks old after emergence (WAE) in 2021 season. While, it appeared during the interval from March 6^th until July 9^th, i.e., the injuries discovered on plants that were thirteen weeks old after emergence (WAE) in 2022 season. Furthermore, the total estimates of B. tabaci during the first growing season (2021) were smaller than those during the second growing season (2022). In the two seasons, a gradual increase in the numbers of B. tabaci on cucumbers was observed during the month of April, indicating that the management of the pest should begin before it reaches its highest level, during the seedling and flowering stages. The results indicated that the influences of weather circumstances and plant development on B. tabaci abundance were highly significant over the two seasons studied and that these variables varied from season to another. As well, the percentages of explained variance were 98.05 and 93.43% in the two seasons, respectively. This information can help establish a greenhouse whitefly management and monitoring programme.