Fumigant activities for three essential oils; Garlic oil (Allium sativum L); Chili pepper (Capsicum annuum L.) and Nigella (Nigella sativa L.) were assessed at different concentrations against the adult and 20-days old larval stages of Tribolium castaneum (Herbst) (Coleoptera: Tenebrionidae) in the laboratory. The accumulative mortality was observed at different exposure periods (3, 5 and 7 days). The residual effect of garlic oil that was the effective oil, on the treated wheat grains was evaluated with respect to histological changes in the liver, kidney, and stomach of rat fed on this treated wheat. The results showed that the mortality rates of treated stages increased with increasing the time of fumigation treatment. Moreover the highest essential oils toxicity at the Median lethal concentration (LC50) values for exposure periods (3, 5 and 7 days) to fumigation were (126, 53, and 47 mg/L air) for adult stage and were (79, 62, and 41 mg/L air) for larval stage, respectively in the case of Garlic oil treatment. While, the lowest essential oils effective was Nigella oil at the Median lethal concentration (LC50) values for exposure periods (3, 5 and 7 days) to fumigation were (3594, 629, and 335 mg/L air) for adult stage and were (1040, 416, and 227 mg/L air) for larval stage, respectively. The toxicity effect of various essential oils against adults and larvae of T. castaneum at the LC50at 7 days fumigation could be arranged in descending order as follows: Garlic oil, Chili pepper oil, and Nigella oil. The histological changes showed that the organs slightly affected at the fumigation for 3 days. It may be concluded that the garlic essential oil is the good effective fumigant to control T. castaneum in the stored products and it recommended that the fumigation period does not exceed 3 days. The garlic essential oil has the potential for applications in IPM programs for stored-grain pests because of its high volatility and fumigant activity and its safety.

This study was designed to characterize the combination of gamma-irradiation and food grade diatomaceous earth(Wolf Creek ranch, California, USA) as diatomaceous earth formulation (DE) treatment against three of stored product insect pests [Sitophilusgranarius(L), Triboliumcastaneum(Herbst.) and Rhyzoperthadominica,(F)]in the laboratory. The study was assessed the killing effect of γ-irradiation at 0,50,100 and 250 Gray against these pests. As well as 0, 0.5, 1.0 and 1.5 g/kg (w/w) concentrations of DE formulation alone or in combination with irradiation were assessed. The obtained results indicated that the mixing between two insect control methods had the combined advantages of quick speed of killing and a high level of safety. Where, the LT 50 have a wide range of values and the combined treatments of γ-irradiation and treatment with DE maybe were the most influencing factors reducing lifespan after treatments. In this laboratory study the combination between DE (1g/kg) and irradiated the tested pests with (100 Gy) of gamma ray produced a potentiation and additive interactions in the case of T. castaneumandR.dominica F adults, while the same combination produced an antagonistic interactionin the case of S. granariusadults. Our finding stated that the use of 'control method' γ-irradiation in conjunction with DE could be a feasible strategic component in Insect Pest Management; IPM in operational modality might be 'sequential' against the tested pests. That is to apply irradiation to eliminate existing census personnel. This is then followed by the addition of DE to the grain to prevent the re-infestation.

Contact and fumigation toxicity of Clove and Dill essential oils were investigated in the laboratory against the adults of Sitophilusoryzae (L.), Rhyzoperthadominica (F.) and Triboliumcastaneum (Herbst.). The results showed that insect mortality was increased by increasing plant oils concentration and the period of exposure. The adults of S. oryzae were the most susceptible insect species under study followed by R. dominica then T. castaneum which was the least sensitive to the two plant oils. The toxicity of Clove and Dill oils against the tested insects was much higher in the fumigant bioassay tests than in the contact method. Clove oil was more effective than Dill oil against the three insect species. The results indicated also that these plant oils could be used as grain protectants or fumigants to control stored products insects

The performance of parasitism by the egg parasitoid, Trichogramma evanescens Westwood (Hymenoptera: Trichogrammatidae) on eggs of Angoumois grain moth, Sitotroga cerealella Olivier (Lepidoptera: Gelechiidae) was investigated under cold storage and gamma irradiation treatments of the host eggs. Cold storage treatment could improve the parasitoid mass rearing techniques and reduced the costs of biological control programs, while gamma irradiation might be used as a supplementary support at the times of high demand. The suitability of the S. cerealella eggs, stored at-20°C for 0.5, 1, or 2 h. as a host for T. evanescens was evaluated. The sensitivity of S. cerealella eggs to gamma irradiation treatments and the acceptability of irradiated eggs for parasitism by T. evanescens females for the parental P and F 1 generations were examined. The results revealed that parasitism was drastically reduced more than adult's emergence and sex-ratio (% of females) after cold storage periods of S. cerealella eggs. Moreover, the parasitism percentages were relatively reduced to (97.1, 96.1, 93.03, and 92.7 %) after irradiating the S. cerealella eggs at 40, 60, 80, and 100 Gy, respectively than the control (97.3% emergence). The percentages of emergence and females' percent were slightly decreased by gamma irradiation doses, while, equal preferred by the F 1 generation of parasitoid that produced from irradiated S. cerealella eggs.