Damaged Allium plants produce and release sulfur allelochemicals, presumably to prevent insect herbivory. Defensive sulfur compounds, particularly dimethyl disulfide (DMDS), are highly toxic for non-adapted species. The toxicity of DMDS in these insects is due to disruption of the cytochrome oxidase system of their mitochondria. The purpose of this study was to compare susceptibility to DMDS in a specialist and a non-specialist insect of Allium plants, i.e., Acrolepiopsis assectella Zeller (Lepidoptera: Acrolepiidae) and Callosobruchus maculatus Fabricius (Coleoptera: Bruchidae) a specialist insect of Leguminosae. Results showed that A. assectella larvae are less susceptible to DMDS than C. maculatus adults. This bruchid becomes more tolerant after a first exposure to 0.2 µ l l − 1 of DMDS, with second-exposure toxicity depending on the time lapse between exposures. Higher second-exposure tolerance could be due to selection and detoxification. To answer this question, the activity of glutathione S-transferase (GST), a key enzyme in the detoxification system, was analyzed after DMDS exposure of C. maculatus adults and larvae and of A. assectella larvae. Exposure to DMDS increased GST activity in C. maculatus adults and larvae. This finding implies that induced GST is involved in C. maculatus tolerance to DMDS. Exposure to DMDS had no effect on GST activity in A. assectella . Adaptations underlying A. assectella tolerance to sulfur compounds are discussed.

A comparison was made for studying the effect of some Essential oils: Rosemary, Garlic, Jojoba and Fixed/Vegetable oils on the important mite pest, Tetranychus urticae. The sublethal concentrations of Rosemary oil (0.125%), Garlic oil (0.5%), Jojoba oil (0.25%) and Vegetable oil (0.125%) were used. Biological tests were carried out for a susceptible laboratory two-spotted spider mites strain reared under controlled conditions of 27±٢°C; 60% R.H. and 16L/8D photoperiod on Sweet Potato leaves. Results showed that Garlic oil caused the highest significant decrease in the number of deposited eggs as compared to the other tested oils. All the oils used have no effects on females mite fertility. Vegetable oil greatly affected the percentage of nymphs that reached adult stages followed by Jojoba oil then Garlic oil while Rosemary had no effects on nymph's developments. Results were tabulated, analyzed, discussed and prepared to be fit in any IPM program for combating these pest animals.

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Pendant sa diapause reproductrice, la teigne du poireau ne présente pas d'activité sexuelle. La reprise de cette activité, après l'hiver, est essentielle au maintient de la population. Chez les insectes qui ont subi la diapause (D), la durée de copulation est plus courte, et la période précédant la copulation est plus longue que chez les insectes matures (M). Deux caractères intéressants sont observés chez les insectes D après la levée de leur diapause: l'apparition d'un pourcentage de doubles copulations et d'insectes qui copulent après la fin de la scotophase, ce, les ♀♀ matures possèdent des ovocytes en rétention dans les oviductes. Le nombre augmente jusqu'à l'âge de 3 jours environ. Par contre, les ♀♀ en diapause n'ont aucun ovocyte à l'émergence. Sous conditions levant la diapause, ces ♀♀ atteignent leur production ovarienne maximum après une douzaine de jours. L'évolution du nombre des ovocytes dépend de la copulation et de la présence de la plante‐hôte. Celle‐ci est essentielle pour la ponte et intervient sur la production ovarienne, aussi bien chez les ♀♀ D que chez les ♀♀ M.

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Mosquitoes play a major role in diseases transmission and distributions, such as filariasis and malaria. The understanding of environmental factors that affect their larval abundance is a key factor for their control. Thus this study aims at investigating mosquitoes' larval abundance in a region known to be endemic for malaria mosquitoes' related diseases in Sharkia Governorate. Measuring environmental factors were: pH, total dissolved solids "TDS", turbidity, water and air temperatures, relative humidity, wind speed, water hyacinths, sun light, water flow, and width and depth of drains in relation with these environmental factors on larval abundance. Six mosquitoes species were recorded and identified in different locations from study sites of 9 drains: Abu Kbeer, Dyarb Negm and Al-Zakazik. Culex pipiens, Culex perexiguus, Culex antennatus, Culex pusillus, Culex sinaiticus and Ochlerotatus detritus were found to be dominant in these localities. Culex pipiens was the most dominant species (79.79%) in all localities. Results were shown and discussed in detail.

Certain effects of different spectral light colors were studied on some biological attributes of the two-spotted spider mite, Tetranychus urticae. Rearing of animals was carried out under conditions of 27±0.5°C; 60% R.H. and 16 L/8 D photoperiod on Sweet Potato leaves. Thus, 5 artificial light colors were applied under controlled laboratory conditions on these animals: blue, red, green, yellow and white Neon. After treatment, the highest number of deposited eggs/female was observed by using the blue color (14.9±0.5 eggs/female) while the lowest one was the yellow (3.1±0.2 eggs/female) compared to 9.9±0.4 eggs/female for the control group. On the other hand, diapause incidence was observed for the target females under conditions of 18±2°C; 60±2% R.H. and the light and dark periods were set at 8 L/16 D, respectively. Results showed that white Neon color caused the highest percentage of diapausing females (88.66±1.8%) followed by green color (78±3.5%), yellow (68.66±2%), the blue color with (54±2%), and finally none of them entered diapause under red color. Results were analyzed and discussed for the aforementioned important economic pest animals.

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