Viability of Nezara viridula (L.) eggs stored at low temperatures for parasitism by Trissolcus basalis (Woll.)

Abstract

Four storage techniques of eggs of green stink bug, Nezara viridula, are compared. Research work aims at utilizing egglaying for posterior parasitism by Trissolcus basalis. Experiment was performed at the Entomology Laboratory of the Agronomy Department at the State University of Maringá, Maringá PR Brazil. Eight batches of 60 eggs of Nezara viridula, stored according to four techniques, were employed: Technique I: conservation in fridge at 2ºC; Technique II: conservation in refrigeration section of fridge at -10ºC; Technique III: conservation in freezer at -18ï‚°C; Technique IV: conservation in liquid nitrogen at -196ºC. After storage, eggs underwent parasitism by three 2-day-old females of T. basalis for 24 hours. Egg batches were kept in climatized chamber till total emergence and death of wasps. Emergence rate and sexual ratio were recorded. Results showed that high sexual ratio and emergence tax are proportionate to low storage temperature. Conservation at -2ºC and -10ºC do not allow extensive storage periods