Impact of indigenous, genetically modified host plants and oviposition behaviour on certain biological aspects of schistocerca gregaria, forskal,

AB731 Experimental studies were carried out under laboratory conditions (30±5°C and 60±l0% R.H.) to investigate the effect of some local host plants such as field crops (T. aestivum, Z. maize and T. trifolium), vegetable crops (E. sativa, P. sativum, R. sativus and A. porrum), medicinal and aromatic plants (0. basilicum, R. communis, P. oleracea and C. rotundus) as well as natural and transgenic (corn and tobacco) plants on some biological aspects of the desert Locust, S. gregaria (Forsk.). Effect of soil types on oviposition behaviour was performed 10 comparative bioassays. The results indicate that feeding on wheat or corn increased the rates of food consumption (19626. and 26671. mg) and it was prolonged survival of nymphal stage (37.9and 39.7days), and the pre-oviposition period (28.8 and 29 days, respectively). Significant prolongations of adult longevity (48.3 and 49.8 days, respectively) were recorded. In contrast, a high reduction occurred in the fecundity (173.4 and 157.4 eggs) and hatchability (86. and 85%), respectively. Concerning the vegetable crops, application of leek and radish increased the consumed food rates (14806 and 18076 mg), while it was decreased fecundity (166. and 175 eggs), and prolonged life span period (65 and 73 days), respectively, great decrease in hatchability (72 and 74 %) and mortality % of nymphal and adult stages (24 and 36%), respectively were recorded. Feeding on parsley and rocket curtailed survival period of nymphal stage (32 and 33 days), these two vegetables shortened the egg laying period (18 and 18 days) and adults longevity (39 and 39 days), respectively compared to clover as a control (41.5 days). Feeding on castor beans, sweat basil, verdolaga and coco-grass increased the consumed food rates (18841, 19015,28940 and 15684 mg) causing weight loss, with high reduction in fecundity (226, 151, 155 and 171 eggs) of females, respectively. In all experiments, the medicinal plants increased the food consumption rates, nymphal body weight causing high significant reduction in fecundity. While, they were prolonged adult longevity 97.3,67.9,55.0 and 43.5 days, respectively. In general, all of the treated nymphs with either natural or transgenic tobacco plants died before moulting to the next instar. Both natural and transgenic com plants increased duration period, food consumption and mortality percentage but reduced the body weight of treated locust. Concerning soil preference, calcareous soil had the least mean number of egg / pod (51 eggs), longest incubation period (14 days), shortest holes depth (4 cm) and least hatchability (79 %). The medium number of eggs / pod (53), incubation period (14 days), holes depth (4.6 cm) and hatchability (85 %) in the clay soil. The longest holes depth (5 cm) and hatchability (90 %) in the sandy soil.