Effects of two plant oil-based products on the mortality of red palm weevil and morpho-physiological characteristics of palm

The red palm weevil (RPW), Rhynchophorous ferrugineus Oliver (Coleoptera: Curculionidae), is an economically important, tissue-boring pest of date palm in many parts of the world. The aim of the work was to investigate the effects of two plant oil-based products (BRK6 and BRK9) on the mortality of RPW (Exp. 1) and morpho-physiological characteristics of palm (Exp. 2). Laboratory experiments showed that the two mixture of oils BRK6 and BRK9 showed larvicide and adulticide properties. These properties were more pronounced on BRK9 than BRK6. The lethal concentration for 50% of individuals (LC50) calculated by probit, of BRK6 was 0.22% (for the 90% of individuals LC90 = 0.34) while for BRK9 the calculated LC50 was 0.10% (LC90 = 0.66). These data show that a smaller amount of BRK9 oil was required to induce the 50% of mortality of RPW larvae. As regards to the adults, BRK9 and BRK6 were effective only at the highest concentration (2 and 5%, respectively). Finally, injection of BRK9 into the palm trunk showed to promote chlorophyll content and photosynthesis of leaves thanks to a good translocation of zinc.