The Effectiveness of Phytochemical Components and Climatic Factors on Population Fluctuation of the Spider Mite, Tetranychus urticae Koch on Sweet Pea and Pea Crops

Studies were conducted to define the level infestations of sweet pea and pea crops to the infestation of the spider mite, Tetranychus urticae Koch, and its predatory mite Amblyseius swirskii (Athias-Henriot) during two successive seasons (2016-2017 and 2016-2017) at  El- Ayyat - Giza Governorate. Results appeared that the infestation of two cultivars by T. urticae was begun in the first week of October under greenhouse conditions. Progressively increased till its peaks in the third week of June for (sweet pea) and in the first week of February for (pea) during the two successive seasons. Through two consecutive seasons, sweet pea cultivar was the most highly sensitive than pea, arranged in a descending order as follows: sweet pea (75.58, 74.37 and 74.19%), (76.30, 75.87 and 74.95%) and pea (24.41, 25.62 and 25.80%), (23.96, 23.51 and 25.04%). Subsequently, sweet pea cultivar highly susceptible (36.62±3.236), (47.75±4.395) and (45.73±4.193) adult, immature and egg, respectively in season 2017-2018 and the lowest infested are pea cultivar (10.71±1.249) (13.66±1.632 ) and (14.61±1.729) adult, immature and egg, respectively in season 2016-2017. Cultivars (sweet pea and pea) contain remarkable rates of the predatory mite, A. swirskii through two successive seasons. Phytochemical contents were evaluated in uninfested and infested leaves at peak infestation and the final season of 2017. In addition, there is a positive relationship between mite infestation levels and total carbohydrates and nitrogen in sweet pea and pea leaves, however a negative relationship found with total phenolic compounds. Infested leaves of sweet pea and pea cultivars contained a low concentration of phosphate and potassium (1.065, 2.165) & (0.54, 1.17) at the late season.