Parasitoids and Predators of Egyptian Alfalfa Weevil Hypera brunnipennis (Boheman) at Kafr El-Sheik and Gharbia Regions

Abstract

The Egyptian clover, Trifolium alexandrim L. occupies about three million feddans (1,260,000 hectares) of winter cultivated acreage the Arab Republic of Egypt (ARE). Farther, it acts as the major fodder crop and a soil reclaiming agent. The Egyptian alfalfa weevil (EAW), Hypera brunnipennis (Boheman) (Coleptera: Curculionidae) is a damaging insect pest species to this important crop. Population fluctuations of both larvae and adults of EAW were monitored during 2019/2020 and 2020/2021 clover growing seasons at Sakha location (Kafr El-Sheikh) and Segeen El-Kom regions (Gharbia governorate). At each location, 3-4 peaks of the insect population densities were recorded annually. The parasitoids, emerging from EAW were identified, collected and their seasonal densities were recorded from the host adults. From the host adults, Microctonus sp (Hymenoptera: Braconidae) was recorded, while Bathyplectes curculionis (Hymenoptera: Ichneumonidae) emerged from the host larvae. Parasitism of H. brunnipennis adults ranged between 0.99 and 1.72%, while that of the host larvae ranged between 0.89 and 4.64%. The correlations between the number of host and number of parasitoid were highly significant positive (0.686-0.950) in case of adults and 0.739-0.949 in case of larvae. Two major predators were observed as related to larvae and adults of Hypera brunnipennis ; Chrysoperla carnea Stepheus and spiders. Also, highly significant positive correlations were found between the number of H. brunnipennis larvae and each of Ch. Carnea larvae (0.680-0.860) as well as spider complex (0.730-0.860).