Sugar pea leaf contents and their influence on population fluctuations of Tetranychus urticae under field conditions at Ismailia governorate

Abstract

A field trial on three sugar pea (Pisum sativum (L.), Fabaceae) cultivars was conducted during the winter season of 2022-23. These cultivars were from two distinct varieties: macrocarpon (cv., Snow Wind and Sugar Lace) and saccharatum (cv., Super Sugar Snap). The aim of the study was to investigate the influence of sugar pea leaf contents and weather conditions on the population fluctuations of Tetranychus urticae Koch (Prostigmata: Tetranychidae). The results showed that T. urticae counts were found to be related to total carbohydrate, soluble sugar, flavonoid, phenol, chlorophyll, and carotenoid contents in the three cultivars throughout the season. The study"s findings revealed that mite densities, including adult, nymph, and egg counts, varied between cultivars, indicating different degrees of infestation. Surprisingly, no predators were observed on any of the three cultivars. The "Sugar Lace" had the highest phenol content and the lowest mite densities. Furthermore, it consistently showed higher levels of flavonoids than the other cultivars. Conversely, "Snow Wind" and "Super Sugar Snap" have higher carbohydrate, soluble sugar, chlorophyll, and carotenoid levels, as well as higher mite population. The variation in infestation among cultivars was, therefore, attributed to changes in leaf phytochemistry. According to the study"s results, including pest-resistant cultivars into Integrated Pest Management (IPM) programs could be beneficial in mite pest control. Selecting cultivars with good phytochemical profiles is a long-term solution for reducing the need for chemical control.