Potentials of essential oils of Chenopodium ambrosioides L. and Cupressus sempervirens L. against stored maize pest, Sitophilus zeamais Motschulsky

Abstract

Maize is cultivated worldwide and used as food for man and animals as well as in fuel production is usually attacked and destroyed during storage by Sitophilus zeamais. With inaccessibility to the highly toxic non-biodegradable synthetic pesticides, poor peasant farmers are left just with the choice of locally available less toxic plants as pesticide alternatives. It is with this in mind that we tested the insecticidal potentials of essential oils of Chenopodium ambrosioides and Cupressus sempervirens against S. zeamais on stored maize. Mortality, progeny inhibition, repellence and persistence were tested. Pesticidal abilities of both oils increased with dose of application. 200 μL/kg of Ch. ambrosioides caused 100% mortality in 72 hours as well as completely inhibited progeny production. 8μL of both oils were repellent to the weevils. The persistence of both oils however dropped to zero within two weeks. Therefore both plants stand recommended as low persistence botanicals against S. zeamais.