Efficacy of Crude and Purified Chitinases (SsChi50) Extracted from Offal Red Scorpion Fish in Biological Control of Chickpea Weevil (Callosobruchus maculatus L.)

In the tropical zone, Callosobruchus maculatus (Coleoptere: Bruchidae) is one of the most important pests of seeds of chickpea (Cicer arietinum). The infestation starts in the fields and continues in the stocks where the damage can be considerable in the absence of any protective measures. The importance of this damage justifies the development of appropriate control methods. In the context of biological control as an alternative to chemical control, the crude and purified chitinases SsChi50 extracted from the red scorpion fish offal were tested for their possible role as insecticide on the stored-product insect Ca. maculatus at various doses, respectively (3, 6, 9, 12, 15, 18, 21 and 24%), (1, 1.5, 2, 2.5 and 3%). The biotests were conducted in laboratory conditions (temperature and relative humidity) maintained at 28C and 75%, respectively. The results showed that the crude and purified chitinases (SsChi50) tested possess insecticidal activity against Ca. maculatus. The crude and purified chitinases at doses of 24 and 3%, respectively, exhibited great biocidal power against insects as we experienced 100% mortality after only 1 h of exposure to treatment. The 50% lethal dose (LD) at each time of exposure was estimated. This allows us to move forward so that the crude and purified chitinases extracted from the red scorpion fish offal tested can be used as bioinsecticide for the control of Ca. maculatus populations of pests of stored foodstuffs. Practical Applications We develop a novel bioinsecticide which consists of crude and purified chitinases extracted from fish offal (scorpion fish). The biotests conducted in laboratory conditions revealed that this crude and purified chitinases extract has 100% insecticide activity after 1 h contact at doses of 24 and 3%, respectively. The originality of this work therefore lies in the fact that there are no studies on the use of chitinases extracted from marine biomass as bioinsecticide.