Medium-Sized Lepidopterous Rearing System Using Multicellular Rearing Trays

Abstract

We modified a previously described disposable rearing container consisting of a multicellular plastic tray and heat seal cover. A clear plastic tray that consisted of 32 individual rearing cells thermo-formed from 15-mil polyvinyl chloride plastic and a cover of 2-mil Mylar perforated with 25 pinholes/2.54 cm2 for gas exchange and coated on one side with a heat sensitive adhesive met our requirements. Experiments were conducted to compare larval developmental time, pupal size, and pupal production for southwestern corn borers, Diatraea grandiosella Dyar; fall armyworm, Spodoptera frugiperda (J. E. Smith); corn earworms, Heliothis zea (Boddie); and tobacco budworms, H. virescens (F.), reared on diet in 30-ml cups with paperboard caps with those reared in the trays. The number of days required for larvae to develop to pupae was the same for cups and trays. Southwestern corn borer and corn earworm pupae recovered from trays were 8-11% smaller than those recovered from cups. About 9% more fall armyworm and tobacco budworm pupae were collected from cups than from trays. Equal numbers of corn earworm and southwestern corn borer pupae were collected from the two containers. Procedures and equipment for using the trays in a medium-sized rearing program and advantages of their use are discussed.