Climatic variables affecting the population density of the phytophagous mite Tetranychus urticae (Acari: Tetranychidae) infesting the common beans Phaseolus vulgaris plantation

Abstract

Climatic variables affecting the population density of the twospotted spider mite (TSSM), Tetranychus urticae Koch (Acari: Tetranychidae), were determined in a field of common bean, Phaseolus vulgaris L., a plantation. This investigation was conducted over two successive autumn seasons from the second week of September to the first week of December in the years 2021 and 2022 at the Agriculture Research Station located in Ismailia Governorate, Egypt. T. urticae populations exhibited pronounced fluctuations throughout the cropping season in relation to variations in average temperature and relative humidity. The initial infestation of T. urticae was observed in the second week of September, 13 mites/leaf during the first season, which increased to 158 individuals/leaf during November in the
same season. The highest population peak was noticed at 260 individuals/leaf in December of the second season. The results showed that climatic factors such as temperature and relative humidity have a significant impact on the prevalence and population densities of T. urticae on the common beans, Ph. vulgaris during the second autumn season.