Effect of Some Control Programs and Weather Factors on Population Density ofBemisia tabaci Infesting Squash Plants (Cucurbita pepo L.)

Squash is heavily infested by the white fly, Bemisia tabaci Genn.(Hemiptera: Aleyrodidae) resulting in a huge loss in yield and quality directly by feeding on sap, causing physiological problems in plants, and transmitting viral diseases.This study was conducted during two successive seasons of 2023 and 2024 to evaluate biological and mix control programs compared with insecticides on squash crop under field conditions to control whitefly B. tabaci.The trials were carried out in Research Farm at El-Nubaria Research Station, El Behiera governorate, Egypt.Inspection was made once a week to determine the population density of whitefly.In the chemical treatment we used one of these pesticides (Buprofezin or Super alpha) after one month of transplanting, we applied first insecticide and other applications were done at fifteen days.In the mixed treatment, we used one of these pesticides (Buprofezin or Super alpha), Beauvaria bassiana and release the predator Chrysoperla carnea alternately every 15-day intervals until end of the season.In biological control, we carried out field trials to study the efficacy of C. carnea & B. bassiana in alternative ways at 15-day intervals.General mean of reduction of whitefly was revealed for Mix control (88.75% and 87 %) during season 2023 and season 2024, respectively.The estimated yield of squash crop post application of the treatments was significant by higher (4.848 & 4.572 ton/fed.) for chemical control, followed by Mix control (4.1064 & 4.020 ton/fed.)followed by biological control (2.925.6&3.8748 ton/fed.)Compared to (2.6172 & 2.7468 ton /fed.) for the untreated check for season of 2023 & 2024, respectively.The effect of some weather factors such as mean temp.& mean R.H. were evaluated on population density of Bemisia tabaci, Although, a high benefit and greatest production were obtained with the use of chemical control, the author is under the impression of using the Mix control as it is desirable treatment for its environmental safety.