Insecticidal Impact of some Natural Oils and their Nano -Emulsions on Sitophileus oryzae

Abstract

In vitro studies were conducted to evaluate the effects of essential oils (EOs), Cymbopogon citratus, Syzygium aromaticum and their nano-emulsion (NEs) by mixing with grains against Sitophilus oryzae (L.). Malathion was used as a standard reference and had the highest adverse effect among those followed by NEs and EOs, since % mortality, % reduction of progeny S. oryzae adults raised,and % loss of wheat grains decreased with high concentration and time. Malathion has a highly toxic effect, followed by NEs and EOs, where the LC50 values of malathion, S. aromaticum nano-emulsion, C. citratus nano-emulsion, S. aromaticum oil and C. citratus oil were (835.6 & 277.0), (15166.4 & 9516.3), (18817.0 & 13333.4), (17232.7 & 10371.5) and (45342.6 & 15706.1) after one and two weeks, respectively. The mortality rate for malathion was 95%, followed by the nanoemulsions S. aromaticum and C. citratus (83.3 and 70.0%) and EOs (76.7 and 66.0%), respectively. While the percentage of reduction in progeny at the high concentration of malathion was 93.5, and was 94.6 and 76.6% for NEs, and 91.8 and 83.7% for EOs, respectively. Moreover, Malathion had the lowest percentage of wheat grain weight loss, followed by NEs and EOs, compared to the untreated control (29%). Furthermore, NEs have a lower percentage of germination wheat grains. Finally, the use of NEs is a promising eco-friendly tool for the control of S. oryzae .