Repellent and Insecticidal Effects of Basil Essential Oil (Ocimum gratissimum) from Kabylie (Algeria) on Rhyzopertha dominica F. (Coleoptera: Bostrichydae): Impact of Treatment on the Physicochemical and Rheological Qualities of Common Wheat Flour (Triticum aestivum)

Abstract

In Algeria, grain-based products occupy a huge place, both in terms of nutrition and economy. Common wheat (Triticum aestivum) is the second most cultivated cereal after durum wheat (Triticum durum), the latter being often subject to attack from various storage pests. To address this issue, phosphine fumigations are used most of the time. Unfortunately, these types of conventional pesticides have caused the emergence of resistant insect populations, and represents a real danger for the environment and human health. The objective of this study is the introduction of a sustainable biological solution to control Rhyzopertha dominica F. (Coleoptera: Bostrychidae) populations using the essential oil of Ocimum gratissimum. To this end, O. gratissimum essential oil was extracted by steam distillation, then chemically characterised by CGMS. A preliminary study was conducted to demonstrate its insecticidal effects on adults of R. dominica. The impact of the extracted essential oil was also estimated on the mineral fraction and the physicochemical and rheological properties of healthy soft wheat flour, R. dominica infested flour, and treated wheat. After 30 days of incubation, the results showed that the essential oil is active by fumigation. The LD50 is 14.36 (µl/l air) for a TL50 of 153.690 h. The repellent effect was estimated at 64.44 %. The essential oil does not affect the rheological and physicochemical characteristics of the flour, which remain compliant with ISO standards. The mineral fraction showed no significant differences at P-values < 0.05.