ABESTRACT: Experiments were conducted in a private farm cultivated with sugarbeet crop (Top cv.) for the two successive seasons of 2013/2014 and 2014/2015 to determine the economic damage threshold levels of Pegomia hyo-scyami Curtis (Diptera: Anthomyidae) under field conditions in Nobaria region, El-Behaira Governorate, Egypt. The results showed that the relationship between the yield of sugarbeet and the infestation of sugarbeet fly, Pegomia hyoscyami Curtis (Pegomyia mixta Vill.) was negative, which is means that an increase in larvae numbers caused a decrease in roots yield and vice-versa.In both seasons, Pegomyia hyo-scyami Curtis larvae registered two seasonal peaks of abundance that occurred in February and March.The determined economic threshold level for Pegomia hyo-scyami Curtis was 19 larvae / plant and the economic injury level was 22 larvae / plant in the first season. But the values were 21 larvae / plant and 22 larvae / plant, in respect, in the second season.

Pesticides are relatively inexpensive and easy tool that can be used and applied for controlling stored-products insects attacking grain elevators, grain stores, flours mills and feed mills. Certain contact insecticides of low mammalian can be applied and sprayed in these stores of grains before or during storage to protect them from insect pests or to control established infestations. Four insecticides (lambda-cyhalothrin [Lambada-Magic ® 5% EC], primiphos-methyl [Actellic ® 50% EC], chlorpyrifos [Magic-phos ® 48% EC] and spinetoram [Radiant ® 12 %SC]) were tested against adults of Sitophilus oryzae (L.) and Tribolium castaneum (Herbst) , using direct contact application. The response varied with chemical insecticide, insect species and exposure time. Filter paper diffusion method at different doses was used for assaying the different tested insecticides. Spinetoram was highly toxic against T. castaneum after 24 and 48 hrs of exposure. Lambda-cyhalothrin was highly toxic against T. castaneum followed by spinetoram; chlorpyrifos and primiphos-methyl after the period of exposure of 72 hrs. Nevertheless, it could be noticed that the toxic effect of spinetoram (LC 50 =4.12ppm) was close to that of lambda-cyhalothrin (LC 50 =3.28ppm) after exposure period of 72 hrs. Spinetoram was highly toxic against S. oryzae followed by chlorpyrifos, and primiphos-methyl after 24 and 48hrs. Spinetoram was also highly toxic against S. oryzae followed by chlorpyrifos, lambda-cyhalothrin and primiphos-methyl after 72hrs. The results indicated that spinetoram as a novel insecticide is highly toxic to both the red flour beetle T. castaneum and the rice weevil S. oryzae. Implications of these results for stored product insects' management programs would be beneficial.

The influence of constant temperatures (20, 25, 30 and 35 °C) as accumulated heat units (day degrees) on the emergence and stages of development of the pink bollworm (PBW) (Pectinophora gossypiella).has been studied under laboratory conditions of the constant temperatures of 20, 25, 30 and 35°C The observed incubation periods, rate of development, the theoretical lower threshold of development (t 0 ) and the degree days (DD S ) of each stage were estimated. Generally, the obtained results showed a negative relationship between incubation temperatures (°C) and lengths of incubation periods for all PBW stages. Referring to the constant temperatures, the PBW stage periods were varied between 20°C and 35°C, hence, They ranged from 7.2 to 2.87, 30.89 to 7.76, 24.4 to 9.83, 4.28 to 1.26, 6.3 to 2.8 and from 6.1 to 2.6 days for eggs, larvae, pupae, pre-oviposition period, oviposition period, post-oviposition period , consequently. The estimated lower threshold temperature (t 0 ) has been differed according to the developmental stage. The (t 0 ) values were 10. 63, 14.82, 9.28, 12.19, 8.44 and 7.53 °C for eggs, larvae, pupae, pre-oviposition, oviposition, post-oviposition periods, respectively. The thermal units as degree days (DD's) were also calculated for each immature and mature stages. The heat unit's accumulations as a part of IPM could be of benefit for forecasting population of the different PBW stages, which were highly important for the predicting pest population and applying insecticides at the optimum time to obtain timely insect control.