Co-Authors:
Kostyukovsky, M., Volcani Center, Bet Dagan 50250, Israel
Ravid, U., Volcani Center, Bet Dagan 50250, Israel
Shaaya, E., Volcani Center, Bet Dagan 50250, Israel
Abstract:
Currently, the measures to control pest infestation in grain and dry food products as well as quarantine treatments rely heavily upon the use of toxic fumigants and contact insecticides, which pose possible health hazards and risk of environmental contamination. This situation has led to the search for potential safe phyto-chemicals as alternatives to replace the toxic fumigants mainly methyl bromide and other pesticides for insect control. The fumigant activity of a large number of essential oils and essential oil components extracted from aromatic plants was evaluated on the major stored product insects Sitophilus oryzae, Rhizopertha dominica, Tribolium castaneum, Oryzaephilus surinamensis, Ephestia cautella, and also on the cut flowers quarantine pests Bemisia tabaci, Frankliniella occidentalis and Liriomyza huidobrensis. In this studies we could show that several compounds were found to be active fumigants at low concentrations. The most active compound has proved to have similar potency as methyl bromide against major insect pests of dry stored food. In space fumigation, at a mere concentration of 0.5-1.5 mg/l air equivalent to 0.5-1.5 g/m3 killed all adult insects after a 24-h exposure. In pilot tests, using wheat, low concentrations of 50-70 g oil/m3 grain were needed to obtain effective control of the test insects, compared with the recommended concentration of methyl bromide of 30-50 g/m3. Addition of CO2 increased the activity of the oils and facilitated the penetration of these compounds in fumigated grain. Studies with cut flowers quarantine insects showed also great promise. A concentration of 10g and 20g/m3 and exposure time of 2 and 4 hrs respectively were enough to get 100% adult mortality of B. tabaci and F. occidentalis, and 50-60g/m 3 after 2hrs exposure were need to kill L. huidobrensis larvae.