European Corn Borer (Lepidoptera: Pyralidae) Development, Larval Survival, and Adult Vigor on Meridic Diets Containing Marker Dyes

Ostrinia nubilalis (Huübner) were reared on meridic diets containing Sudan red, Sudan blue, and no dye. Two rearing procedures were used: (1) larvae were fed treatment diets throughout development, and (2) larvae were transferred at the 4th instar from diet without dye to treatment diets. Development, larval survival, and adult vigor were evaluated. Both dyes permanently marked larvae, pupae, and adults. Dyed diets and larval transfer each significantly delayed development and reduced survival. Larval transfer also reduced pupal fresh and dry weights. Responses to Sudan red and Sudan blue dyes did not differ significantly. Treatments failed to significantly reduce adult longevity or duration of tethered flight. Direct deleterious effects of the transfer method and failure of the transfer to reduce dye effects indicated that larval transfer was unacceptable for use with internal marking procedures. Both dyes seem acceptable for marking O. nubilalis; however, rearing procedures must compensate for reduced survival and protracted development.