Spatio-temporal distribution of walnut aphids and associated natural enemies in temperate agro-ecological zone of Kashmir Valley

The valley of Kashmir is blessed with a climate suitable for raising a number of fruit and nut crops. Walnut is one such praised favourite nut of many. Walnut trees, one of Kashmir’s most valuable crops, are, however, susceptible to diseases and insect pests that cause significant annual financial losses. As such, it is essential to understand the numerous causes of these problems. Aphids are one of the most common insect pests affecting walnuts. With the aim of studying the population dynamics and distribution of two walnut aphid species viz., Chromaphis juglandicola and Panaphis juglandis, the present study was conducted for two consecutive years 2021 and 2022, in Kashmir, India. For the study, three major walnut producing districts were selected and from each district three villages were surveyed for two years and each site was visited fortnightly. The data revealed that the population of both aphids increased gradually from April to 2^nd fortnight of June and declined rapidly afterwards, reaching the lowest in September. Aphid numbers reached their highest level during the month of June. Moreover, the predatory natural enemies also helped in shaping the aphid population. A total of five natural enemies were also identified during the study.