Disruptive Impacts of Selected Insecticides on Larval Haemogram parameters of the Red Palm Weevil, Rhynchophorus ferrugineus (Coleoptera: Curculionidae)

Document Type : Original Article

Authors

Faculty of Science, Al-Azhar University, Madenit Nasr, Cairo, Egypt

Abstract

The present study was conducted to investigate the effect of three insecticides,pyriproxyfen (admeral), neemazal (azadirachtin) and spinetoram (Radiant), against the red palm weevil Rhynchophorus ferrugineus. Two sublethal concentrations of each compound had been estimated in a preliminary test: LC50: 1067.5 ppm, LC75: 2317.5 ppm (pyriproxyfen), LC50: 14600 ppm, LC75: 27100 ppm (neemazal), LC50: 18.37 ppm, LC75: 88.60 ppm (spinetoram). These concentrations were tested against the immune cells (Total hemocyte count, Differential hemocyte count and hemocyte deformations).  Depending on the present study, five types of hemocytes were observed as prohemocyte, granulocyte, plasmatocyte, oenocyte and spherulocyte. Total hemocyte count was significantly increased irrespective to the insecticide. All insecticide induced the prohemocyte while the other types were declined. However, the tested insecticide exhibited pathological symptoms on insect haemocytes morphology in the cell membrane, cytoplasm and nucleus.  v

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