An improved foolproof device for eggs’ sterilization of Corcyra cephalonica (Stainton)

Abstract

Mass rearing of numerous biological control agents depends on large amounts of eggs of factitious hosts like rice meal moth, Corcyra cephalonica (Stainton) (Lepidoptera : Pyralidae). Corcyra eggs sterilization is required before they are used for parasitisation by Trichogrammatids. To meet the requirement of eggs sterilization of this insect, a new innovative device was invented, fabricated and studied. It consisted of an enclosed structure having semi-circular shaped drawer. An ultra violet (UV) tube of 30 W is fixed on the centre of its ceiling to maintain a uniform distance of 35 cm from the eggs to be sterilized. An exposure of 10 minutes to eggs of C. cephalonica was required to get optimum sterilization. As whole body of the device was an enclosed structure, hence, there was no exposure of UV rays to the laboratory workers. The different sized-models (150,100, 50 of “egg cards” required for Trichogrammatids) can be fabricated to meet the diverse requirements. Irradiated eggs were found having no any adverse effects on the abilities of Trichogrammatids parasitisation and its emergence. It can also used for UV sterilization of laboratory materials like glassware, plastic ware, clothes, cotton etc. The period of exposure to the UV light was set using timer. This innovative UV chamber had numerous advantages i.e., the UV rays used had damaged the host embryo. The damaged embryo could not develop into next stage, at the same time damaged embryo found suitable for parasitization of Trichogrammatids. The whole body of the device was made-up of an enclosed struc-ture; hence, there was no exposure of UV rays to the laboratory workers. The different sized-models (150,100, 50 of “egg cards” required for Trichogrammatids) can be fabricated to meet the diverse requirements of clients. As the UV chamber was made up of metal and ply boards, hence, it was durable. The longitudinal flanges provided in the drawer of the device prevented the host egg bearing cards to glide one over other from curved surface. The device was found safe and effective for sterilization of Corcyra eggs and easy to operate.