Available online xxxKeywords: Fumigant toxicity Volatile plant oilsSitophilus granarius (L.) a b s t r a c tOne-week-old adults of Sitophilus granarius (L.) reared on wheat were subjected to pure plant volatile oils of Thuja, Eucalyptus and Peppermint. Volatile oil of Thuja was extracted from unripe fruits of Thuja orientalis plant by water distillation. The objective of the current study was to determine the fumigant toxicity of these volatile oils against adults of S.granarius. The fumigant toxicity of the volatile oils was tested against 1week old adults of S. granarius at 28 ± 2 C and 65 ± 5% RH in darkness. The mortality of adults was tested at different concentrations ranging from 20 to 100 ml of Thuja, 10e30 ml of Eucalyptus and 3 e15 ml of Peppermint at different exposure times (24, 48 and 72 h). The results demonstrated that the mortality increased with increases in concentration and exposure periods.The percent mortality of S. granarius reached 91.2, 95.0 and 91.2% when 1-w-old adult exposed to higher concentration of Thuja, Eucalyptus and Peppermint oils, respectively, comparing to 0% in the control after 24 h. After 72 h the percent mortality was 100% at the higher concentration of the three volatile oils. LC 50 and LC 90 were determined for each volatile oil and each exposure period. Data probit analysis demonstrated that concentrations of 70.71 ml Thuja, 16.95 ml Eucalyptus and 10.48 ml Peppermint, recorded 50% mortality after 24 h, however it reached 90% when concentrations increased to 104.04 ml Thuja, 25.48 ml Eucalyptus and 15.92 ml Peppermint after the same period. LC 50 and LC 90 valueswere decreased by increasing the exposure periods. These results showed that the three volatile oils could be applicable to the management of populations of S. granarius (L.).

Culex pipiens mosquito is considered as one of the most dangerous insect pests that affect humans and animals worldwide as they transmit epidemic and fatal diseases. Antennal structure of the normal and irradiated female mosquito, Culex pipiens was examined using scanning electron microscopy to study the changes in the antennal segments and associated sensilla when 1e2 days old pupae were irradiated at low dose (20Gy), moderate (40Gy) and high (80Gy). The antenna of the female C. pipiens is filamentous in shape and consisted of scape (S), pedicel (P) and flagellum (F) which has 13 flagellomeres. Various types of sensilla with distinct morphological characters and morphometric features were recorded. Sensilla trichodea are the most abundant sensilla observed, with other types like sensilla chaetica, sensilla basiconica (grooved peg), sensilla coeloconica and sensilla ampullaceal. Morphological changes were recorded to the antennal segments and their associated sensilla due to the doses of gamma radiation (20, 40 and 80Gy) such as shrinkage, curved of sensilla into different directions, irregularity in shape, swollen in some parts and some sensilla gathered into dense collections. These changes were obviously demonstrated at 80Gy and 40Gy doses whereas little malformations were observed when the pupae irradiated with 20Gy dose. The antenna has lost most of different types of sensilla and some of its segments became transparent with high and moderate doses. These changes also recorded in the distal 13th flagellomeres segments with the three used doses of gamma radiation compared to control ones.

To improve the mass rearing of Peach Fruit Fly, Bactrocera zonata different concentrations of Cacao, Curcuma and Selenium were added to the larval diet. The effects of these additives on the biological characteristics were evaluated. The pupal weight, adult emergence, sex ratio, adult survival, pupal production and adult flight ability were studied to evaluate the mass rearing quantity and quality. In addition, the elements compositions of adult stage were carried out as a monitor for B. zonata vitality. The results indicated that the concentrations of 1.0 gm/ kg Cacao, 1.5 gm/kg Curcuma and (0.01 and 0.02 gm/kg) of Selenium were the most pronounced promising concentration to the insect fitness as compared to the other concentrations. In these concentrations, the pupal productions, pupal weights and flight ability of adult flies were clearly higher than the control treatments. Also, the major and trace elements P, S, Cl, K, Ca, Fe, Cu, Mg and Zn of male and female flies previously fed as larvae on selected concentrations of additives were analysed. Addition of 1.5 gm of Curcuma and 1.0 of Cacao increased the Cl of both male and female flies, while addition to both 0.01 and 0.02 gm/kg of Selenium increased the P and Mg contents of the both sexes. Also, some values of tested elements are varied by the different additives; these differences could play an important role in the insect vitality and sex maturation.

The Peach fruit fly, Bactrocera zonata (Saunders) is a serious devastating pest in Egypt. This pest spends in soil from full grown larvae till adult emergence. Therefore, the present study was planned to evaluate the pathogenicity of Steinernema scapterisci against larvae and 1 day old pupae (at different soil depths), and to investigate the effect of gamma radiation on its virulence. The results revealed that adult emergence percentage decrease as the soil depth and S. scapterisci concentration increase. In contrast, the larval mortality increased with S. scapterisci concentration increased. In addition, this study showed that gamma irradiation of S. scapterisci juveniles with 2Gy increased its virulence against both larvae and pupae, which presented by lower LC 50 values than unirradiated S. scapterisci. Subsequently, it could be concluded that 2Gy irradiated S. scapterisci can serve as a bio-tolerated control method for B. zonata.

Morphology, distribution and function of the sensilla associated with mouthparts of female mosquito, Culex pipiens (Diptera: Culicidae) were studied by using the scanning electron microscope. The female mosquito mouthpart is a piercing and sucking type and carrying many sensory organs which plays major role in host seeking, and oviposition behaviour of mosquitoes. Six types of mouthpart sensilla have been identified and described, Sensilla trichoidea, chaetica, basiconica, Capitate peg, campaniformia and squamiformia. Females mosquito were irradiated as pupae with 20, 40 and 80 Gy of gamma radiation to investigate their effect on mouthparts sensilla. Dose of 20 Gy had slight effect on the different types of the sensilla as compared with the control. Features of malformation observed in the maxillary palp segments at this radiation dose include falling of some scales (sensilla squamiformia) at certain parts of the 1st segment leaving vacuoles. At 40 Gy, the maxillary palp segments were liquefied in some areas leaving undistinguished shape. At the highest dose 80 Gy, the tip of labial palps had many tears and showed were most affected, especially, at the trichoid, basiconic and chateica sensilla. All these malformations may lead the mosquitoes to not reaching the host, impeding their ability to transmit diseases or killing the mosquitoes, and this is the main objective of this study.

(NCRRT) for her critical comments, proceeding facilities, offering help in revising the manuscript, valuable support and kind help.

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