Population dynamics of Oligonychus afrasiaticus in the southern Arava Valley of Israel in relation to date fruit characteristics and climatic conditions

摘要

1 Oligonychus afrasiaticus, the old world date mite, is a serious pest of dates in North Africa and the Near East, including Israel. It attacks and rapidly develops when the fruit is young and green. Mite phenology is affected by date cultivar, but the relationship between fruit characteristics and mite population development is unknown. 2 We report that mite establishment on the main cultivars grown in Israel, 'Medjool', 'Barhi' and 'Deglet Noor', began only when the water content of the fruit increased to >= 84%. Fruit bunch architecture and resistance to penetration, as well as sugar composition and content, were not key factors in mite establishment. 3 Later in the season, when total sugar levels reached >= 150 mg/g fresh fruit weight, total soluble solids comprised 15% and water content decreased to <=75%, mite populations declined. 4 Yearly climatic variations could be responsible for phenological asynchrony between the pest and fruit development.