STUDIES ON INSECT PREDATORS AND SPIDERS IN SUGAR BEET FIELDS AT KAFR EL-SHEIKH REGION

Abstract

Field and laboratory experiments were carried during three consecutive sugar beet seasons; 2002/03, 2003/04 and 2004/05. The field plots were included in 25-30 feddans assigned annually for conducting experiments of Sugar Beet Research Program (Sugar Crops Research Institute) located at Sakha Agricultural Research Station. Laboratory Studies were conducted at entomology laboratories of Faculty of Agriculture, Kafr EI-Sheikh, Tanta University and Sugar Crops Research Department, Sakha Agricultural Station.

The study aimed to survey insect pests, insect predators, and spiders occurring in sugar beet fields. In addition, some factors affecting predatory populations were considered:

1. Insect pests inhabiting sugar beet fields:

Sixteen insect pest species, causing a considerable damage, were surveyed. Three species [Gryl/otalpa gryllotalpa L.; Agrotis spp. and Spodoptera littoralis (Boisd.)] resulted in poor plant establishment. Three species were severe defoliators; S. littoralis, S. exigua (Hubn), and Cassida vittata Viii. Five mining insect species invaded different plant parts; Pegomyia mixta Viii., Scrobipalpa ocellatella (Boyd.), Lixus junci Boh, Temnorhinus brevirostris Gyll and Ostrinia nubilalis Hubn. Also, five insect species fed on plant sap., and caused leaf curling; aphids, Bemisia tabaci Gann., Nezara viridula L., Empoasca spp. and Thrips !abaci Lind.

2. Insect predators inhabiting sugar beet fields:

Survey studies were carried out using six collecting techniques: pit­ fall trap, vacuum machine (D-vac), sweep net, leaf-litter, Tullgren funnel and water pan trap.