Effect of essential oils on mortality and repellency of maize weevil (Sitophilus zeamais) (Motschulsky) under laboratory condition of Lamjung campus

Abstract

Maize (Zea mays) is a crucial staple food crop and consumption of maize products has increased around the world due to the expansion in the global population. Maize weevil, Sitophilus zeamais (Motschulsky) (Coleoptera: Curculionidae), has been an increasing concern during the storage of the grain. Although insecticides can curtail the jeopardy of maize weevil, development of toxic residue and resistance by pests pose a constant threat in its adoption. The essential oils could provide a viable and safer alternatives to control the pest. Hence, an experiment was carried out at the Entomology Laboratory of the Institute of Agriculture and Animal Science to assess the fumigation and repellent effects of seven different essential oils viz. Mentha (Mentha arvensis), Lemon grass (Cymbopogon citratus), Fresh basil (Ocimum basilicum), Eucalyptus (Eucalyptus globule), Palmarosa (Cymbopogon martini), Citronella (Cymbopogon winterianus) and Juniper berry (Juniperus recurva) at 50 μl and 100 μl for fumigation mortality and 0.125% and 0.25% for repellency against maize weevil. The effects of the oils were dosage-dependent, and there was a progressive increase in insect death as concentrations increased. Furthermore, eucalyptus oil resulted in the highest mortality at 100 μl and repellency at 0.25%.