Lethal doses of ozone for control of all stages of internal and external feeders in stored product
Authors: Lise S Hansen,Peer Hansen2and, Karl-Martin V Jensen1
BACKGROUND:Gaseous ozone (O3) has potential for control of insects in stored grain. Previous studies have focused on freely exposed insects. Immatures of internal pests (e.g.Sitophilusspp. and most stages ofRhyzopertha dominicaF.) are protected within kernels and probably require higher doses and/or longer treatment times for full control. A laboratory study determined the doses of ozone necessary for full control of freely exposed and internal stages of eleven stored-product pest species. Test insects were three species ofSitophilus, R. dominica, Tribolium confusumJacquelin du Val,T. castaneumHerbst,Plodia interpunctellaHübner,Sitotroga cerealellaOlivier,Oryzaephilus surinamensisL.,Ephestia kuehniellaZeller andStegobium paniceumL. Insects were exposed to continuous flows of ozone in doses of 10–135 ppm and exposure times of 5–8 days. Dose-mortality bioassays were conducted on three species ofSitophilusandP. interpunctella.
RESULTS:Freely exposed stages (with a few exceptions) were controlled with 35 ppm of ozone for 6 days. Full mortality of internal stages within kernels required exposure to 135 ppm for 8 days.