@article { author = {Bakr, Reda and Ghoneim, K. and G., Al-Dali and A., Tanani and S., Bream}, title = {Lethal efficacy of the chitin synthesis inhibitors flufenoxuron (cas-101463) and lufenuron (cga-184699) on Schistocerca gregaria (orthoptera: acrididae)}, journal = {Egyptian Academic Journal of Biological Sciences. A, Entomology}, volume = {1}, number = {1}, pages = {1-12}, year = {2008}, publisher = {Egyptian Society of Biological Sciences}, issn = {1687-8809}, eissn = {2090-0813}, doi = {10.21608/eajbsa.2008.15754}, abstract = {The present work was carried out aiming to assess the lethal activity of the chitin synthesis inhibitors (CSIs): Flufenoxuron (CAS-101463) and Lufenuron (CGA-184699) on the desert locust Schistocerca gregaria.  Five concentration levels of each CSI: 1000, 500, 250, 125 and 62.5 ppm, were given through fresh clover leaves as a food to the newly moulted (4 th or 5th) instar nymphs or the late-aged 5th instar nymphs.  All observations and results were recorded after 24 hours of feeding. During few days after feeding of the newly moulted penultimate instar nymphs on Flufenoxuron treated food, the mortality increased (40%) at the highest concentration level but decreased (10%) at the lowest concentration level. The lethal action of Flufenoxuron appeared also along the later days of penultimate instar at the lower concentration levels . With  few exceptions, the mortality of the last instar nymphs increased proportionally to the ascending concentration level. At the highest concentration level, the lethal action was lately exhibited in the adult stage at the lower concentration levels. Lufenuron exerted its mortal activity on the penultimate instar nymphs proportionally to the concentration level. No certain trend of the mortality of last instar nymphs could be appreciated by Lufenuron. Also, some deaths were observed among adults varying between 40% (at 250 ppm) and 14.2% (at 62.5 ppm). After treatment of the newly moulted last instar nymphs, the available results show no certain trend of mortality, whether nymphal instar or adult stage. After treatment with the highest concentration level, the lethal effect was easily detected which spread along the nymphal instar. With regard to the adult stage, the greatest mortality was observed at 250 ppm. Among the newly moulted last instar nymphs, the mortality ascended as the conc. level of Lufenuron was increased but estimated in 49% at both 250 and 500 ppm. Several adult mortalities were recorded but in no certain trend. After treatment of the late-aged last instar nymphs, the lethal activity of Flufenoxuron, to some extent, increased consecutively to the ascending concentration level in both nymphs and adults.  The highest lethal effect of Lufenuron on late-aged last instar nymphs (30%) was observed at the higher two conc. levels. However, the lethal effect of Lufenuron on nymphs was lately recorded. Also, increasing adult mortality paralleled to the ascending concentration level with an exception.}, keywords = {Desert locust,Schistocerca gregaria,Chitin synthesis inhibitors,Flufenoxuron,lufenuron,mortality,survival potential}, url = {https://eajbsa.journals.ekb.eg/article_15754.html}, eprint = {https://eajbsa.journals.ekb.eg/article_15754_4dbec9c10a6cc3b55d39bb64ea922694.pdf} } @article { author = {Hussein, Mohamed and Hamouda, Laila and Bakr, Reda and A., Hassan and F., Elsokary}, title = {Effect of Cascade, Oriza sativa bran extract and Karate on fine structure of the ovary of Schistocerca gregaria.}, journal = {Egyptian Academic Journal of Biological Sciences. A, Entomology}, volume = {1}, number = {1}, pages = {13-21}, year = {2008}, publisher = {Egyptian Society of Biological Sciences}, issn = {1687-8809}, eissn = {2090-0813}, doi = {10.21608/eajbsa.2008.15761}, abstract = {The ultrastructure changes in the ovarian follicle of normal adult females and those developed from treated 5th nymphal instar of Schistocerca gregaria with LC50 of anti-chitin compound (cascade), plant extract (Orizasativabranextract)and synthetic pyrethroid (Karate) were examined. In the present study electron micrographs of follicle cells of treated adult females with previous compounds showed a degeneration of ovarioles and oocytes .There is also evidence of mitochondrial disintegration . It is also noticed that  vacuoles were increased and enlarged in follicle cells and yolk bodies were cracked mostly in two halves.}, keywords = {Schistocerca gregaria – Orthoptera,IGRs,plant extracts- ovaries,Ultrastructure,histopathological aberrations}, url = {https://eajbsa.journals.ekb.eg/article_15761.html}, eprint = {https://eajbsa.journals.ekb.eg/article_15761_56206964c189a2ca2ef0faf292ba41ba.pdf} } @article { author = {Bakr, Reda and Ghoneim, K. and S, Bream, A.S. and G., Al-Dali and A., Tanani}, title = {Ultrastuctural changes in certain nymphal tissues of schistocerca gregaria (orthoptera: acrididae) by some chitin synthesis inhibitors.}, journal = {Egyptian Academic Journal of Biological Sciences. A, Entomology}, volume = {1}, number = {1}, pages = {23-39}, year = {2008}, publisher = {Egyptian Society of Biological Sciences}, issn = {1687-8809}, eissn = {2090-0813}, doi = {10.21608/eajbsa.2008.15765}, abstract = {Flufenoxuron caused a blockage of the production of cuticle of the last instar nymphs since its thickness remained unchanged while that of control congeners increased in thickness as the development proceeded. The formation of endocuticle was prohibited, so the epicuticle and exocuticle did not properly attached to the epidermis. The epidermis appeared with irregularly distributed cells underneath the cuticle. On the other hand, Lufenuron exhibited more dangerous effects. The epidermis was degenerated and detached from the endocuticle which could not distinguish from the exocuticle. The available electron micrographs reveal several dangerous effects of Flufenoxuron on the thoracic muscles such as distortion shape of the Z line and disorganization of A, I and H bands, appearance of gaps and vacuoles in the sarcomere. Similar effects were recorded for Lufenuron beside the complete distortion of the Z disc. Flufenoxuron affected the ultrastructure of mid-gut such as destruction of the cell vacuolization and a rupture of the epithelial walls. In respect to Lufenuron, some signs of morbidity in both nuclei and cytoplasm of the epithelial cells were observed, such as curling and rupturing of the microvilli and the formation of large area of necrosis in a vacuolated cytoplasm. Flufenoxuron caused several ultrastructural changes in the intracellular organelles of last instar nymphs. The mitochondria appeared generally in an irregular shape. Their two membranes were not demarcated with loss of cristae but increased granules. Morphology and of Golgi bodies was remarkably influenced and some of them were fragmented into small particles. The secretion granules associating the Golgi bodies disappeared. The limiting membranes of lysosomes were ruptured. The margination and nuclear chromatin seemed to be early changed leading to the cell death. Lufenuron, on the other hand, caused many serious ultrastructural changes since the mitochondrial cristae were partially or totally lost. Some mitochondria appeared swollen with irregular shape while others appeared greatly elongated with prominent cristae. The mitochondrial membranes were not demarcated, and some mitochondria were filled with dark electron dense granules. Also, the nuclear membrane was disrupted. As well as, the lysosomes and Golgi bodies were hypertrophied with different deformities.}, keywords = {Schistocerca gregaria,Flufenoxuron,lufenuron,nymphal instar,Ultrastructure,histopathology,integument,Muscles,mid gut,mitochondria,lysosomes,Golgi bodies,nuclear membrane,cytoplasm}, url = {https://eajbsa.journals.ekb.eg/article_15765.html}, eprint = {https://eajbsa.journals.ekb.eg/article_15765_dee08f34bcc7895fd4a06509338beb7f.pdf} } @article { author = {Bakr, Reda and Ghoneim, K. and G., Al-Dali and A., Tanani and S., Bream}, title = {Efficiency of the chitin synthesis inhibitor lufenuron (cga-184699) on growth, development and morphogenesis of Schistocerca gregaria (orthoptera: acrididae).}, journal = {Egyptian Academic Journal of Biological Sciences. A, Entomology}, volume = {1}, number = {1}, pages = {41-57}, year = {2008}, publisher = {Egyptian Society of Biological Sciences}, issn = {1687-8809}, eissn = {2090-0813}, doi = {10.21608/eajbsa.2008.15767}, abstract = {This paper deals with the objective of investigating the effects of Lufenuron (CGA-184699) on the growth, development and morphogenesis of the desert locust Schistocerca gregaria. Five concentration levels (1000, 500, 250, 125 and 62.5 ppm) were given through the fresh plant food to the newly moulted (4th or 5th ) instar or late-aged 5th instar nymphs. All results were obtained 24 h after feeding. The growth of Lufenuron-treated nymphs was profoundly inhibited because their weight gain was drastically  reduced. Such reducing action of Lufenuron  was dose-dependent after treatment of 4th instar nymphs but at the higher two concentration levels after treatment of newly moulted 5th instar nymphs and at the higher three concentration levels after treatment of late-aged  5th instar nymphs. After treatment of the last instar nymphs, early or late-aged, the developmental rate detrimentally regressed as a response to the prohibiting action of Lufenuron on the development. In contrast, such rate was promoted during significantly shortened duration after treatment of 4th instar nymphs, may be to accelerate the development for avoiding additional adverse effects of Lufenuron. Lufenuron exhibited an inhibitory effect on the adult emergence after treatment of last instar nymphs, regardless of the timing of treatment. On the other hand, Lufenuron exerted no effect on this vital process after treatment of 4th instar nymphs. Moreover, the present compound, at certain concentration levels, induced the adults to emerge in a rate more than that on control congeners. However, the emerged adults suffered a morphogenic action of Lufenuron because different deformed females were produced in increasing % as, at least, the higher three concentration levels were increased. In addition, the adult females spent only shortened longevity and then died. The shortening effect was dose-dependent after treatment of 4th instar nymphs. }, keywords = {Schistocerca gregaria,lufenuron,Growth,Development,emergence,morphogenesis,longevity}, url = {https://eajbsa.journals.ekb.eg/article_15767.html}, eprint = {https://eajbsa.journals.ekb.eg/article_15767_1b751405303e4d37f59388477190c3d6.pdf} }