Comparative Assessment of Certain Insecticidal Compounds on the Development and Adult Performance of Red Palm Weevil, Rhynchophorus ferrugineus Olivier (Coleoptera: Curculionidae).

Document Type : Original Article

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Department of Zoology and Entomology, Faculty of Science, Al-Azhar University, Madinat Nasr, Cairo, Egypt

Abstract

The red palm weevil Rhynchophorus ferrugineus is a serious pest of date palm in different regions of the Middle East. The present study was carried out to evaluate comparatively the effects of pyriproxyfen (insect growth regulator), neemazal (a plant product) and spinetoram (a bacterial product) on growth, development and adult performance of this insect pest. The early 5th instar larvae were treated with five sublethal concentrations of each compound. The most important results can be summarized as follows. Both larval duration and weight were considerably reduced by Spinetoram. Pyriproxyfen significantly reduced the larval duration only at 4000 ppm (7.2±2.97, compared to 11.7±1.6 days control insects) but Neemazal could not exhibit a remarkable effect.  The strongest reducing effect on larval weight was recorded for Pyriproxyfen, since the growth inhibition% was determined as 49.10, 48.58 and 38.04, at 4000, 2000 and 1000 ppm, respectively.  Pupation was inhibited by all tested insecticidal compounds and the pupal duration was significantly shortened, except at the lower three concentrations of Neemazal. Some deformations had been recorded only in adults, irrespective of the tested compound. The adult longevity was significantly shortened at the higher concentrations of each compound.

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