Toxic and Repellent Effects of Four Plant Oils against the Red Flour Beetle, Tribolium castaneum (Herbst)

Abstract

The present study was carried out to evaluate the toxic and the repellent effects of four essential plant oils Coconut oil (Cocus nucifera L.), Gingeroil (Zingiber officinale Rosc.), Jojoba oil(Simmondsia chinensis L.) and spearmint oil(Mentha spicata L.) against the adult of red flour beetle. Three concentrations of each plant oils were used, 0.5, 1 and 2%. The LC50, LC90 values were also calculated using Probit analysis technique. LC50, LC90 values of coconut, ginger, jojoba and spearmint oils after 24, 48, 72 and 96 hrs intervals were determined. Results revealed that ginger oil was more effective against Tribolium castaneum. Data of 96 hrs showed that ginger still the most effective oil against the pest (LC50 = 0.37 and LC90 = 0.86%). The LC50 values were 0.56, 0.66 and 1.17% and LC90 values were1.09, 1.19 and 2.76% for coconut, spearmint and jojoba, respectively. Repellency test was conducted at 2% concentration for each oil. Data were recorded at 1, 3, 6, 12 and 24 hrs after insect release. The results showed that the highest repellent rate (45.08) was recorded for ginger and spearmint oil, while the lowest repellent rate (15.01) was recorded for jojoba oil after 24 hrs.