Insect control by gamma‐irradiation: An appraisal of the potentialities and problems involved

Abstract

Experimental sources of cobalt‐60, made radioactive by neutron irradiation, have been used during recent years for investigating the radiation susceptibility of insect pests. Lethal and sterilising effects have been examined on species, strains and developmental stages to evaluate the dose levels required for commercial treatment. The technical feasibility of using radiation as an insecticide is now established. Results of research and problems of application are examined in relation to the two potential methods of controlling insect pests by irradiation; indirect control by the release of sterilised adults and the direct treatment of infested products. Application of the first method, exemplified by work on screw‐worm fly, is limited to very few species by a number of biological requirements. Direct treatment could have wider application for the control of all species infesting stored products. The most favourable products for radiation dis‐infestation are those handled in bulk at particular centres, and for this reason radiation treatment of grain has been examined in detail. The fundamental and applied problems of using γ‐radiation for this purpose are discussed and the relative merits of fumigation and radiation sterilisation are compared. It is concluded that among factors which may influence the success of radiation disinfestation, bulk handling and the incorporation of treatment into established handling procedures must receive primary consideration. γ‐Irradiation may eventually take its place as a useful means of insect control, but it is unlikely to displace conventional methods.

Sterilization of the navel orangeworm,Paramyelois transitella(Walker), by gamma radiation (Lepidoptera: Phycitidae)

“…), was actually eradicated on the island of Curacao through the release of adults sterilized by gamma radiation (Baumhover et al, 1955;Lindquist, 1955). Further discussions of the main factors that affect the success of insect control by this measure were published by Knipling (1959Knipling ( , 1960, Bushland (1960), Cornwell and Bull (1960), and von Borstel (1960).…”

Irradiation of cereal grains and cereal grain products

“…Another effect of irradiation is a direct effect on gametes in the body of a normal adult. Thirdly, the adult insects may not take part in normal sexual activities (Cornwell and Bull, 1960).…”

“…Seasonal production, fluctuation in demand, and good and bad harvests will operate against the efficient use of irradiation (Cornwell and Bull, 1960).…”

Stored‐products entomology in Britain, 1964

“…The investigations covered mode of action of radiation on insect tissues; dose levels for immediate death or reproductive sterilization, effects of radiation on the materials treated; and the development of apparatus in which grain might be treated on a commercial scale. It was shown that a dose of 16,000 rads was adequate to effect reproductive sterilization of all species studied; that this dose had no effect on the milling or baking quality of wheat or had any other deleterious effects; and that it could be applied economically under practical conditions, either by 6oC0 y-radiation or accelerated electrons (Cornwell & Bull, 1959).…”