Green clay aromatized powder formulation for controlling Callosobruchus maculatus (F.) on stored chickpea

Abstract: In Tunisia, the cowpea beetle Callosobruchus maculatus is the most damaging pests of food legume stored grains mainly stored chickpea Cicer arietinum. Its control is based on the use of synthetic fumigants. However, these pesticides have various undesirable effects such as environmental pollution, pesticide residues, toxicity to non target organism and pest resistance, in addition to direct toxicity to users. Thus, safer alternatives are needed. This study reports the effectiveness of two green clay aromatized powder formulations fumigation against adults of C. maculatus and with the crude essential oils as reference. Two essential oils, namely Eucalyptus leucoxylon and E. lehmani, were used. The aromatized powder formulations efficacy was measured by pest mortality, fecundity and fertility. GC-MS analysis showed that α-pinene and 1,8-cineol were the major component of the two oils with respective percentage of 10.43; 22.48% and 54.64; 51.57% for E. leucoxylon and E. lehmani, respectively. Moreover, the aromatized powder formulations exhibited strongest adulticidal activities compared crude essential oils. Indeed, formulations achieved complete (100%) mortality against 76.6; 56.6% for E. lehmani and E. leucoxylon, respectively after 24 h of exposure at the highest concentration. In addition, significant reduction in both fecundity and fertility were observed between crude essential oils and aromatized powder formulations. In fact, fertility rate reached 74.87% for crude essential oils versus 31.05% for aromatized powder formulations. This result suggests the interest of applications of aromatized powder formulations for better pest management in storage structures. Indeed, in developing countries food legumes are major sources for human nutrition.