A COMPARATIVE-STUDY ON CHRYSOPERLA-CARNEA (STEPH)-EGGS WITH AND WITHOUT STALK OF A WITH SEMISYNTHETIC DIEST AND OF A WITH APHIDS FED CULTURE WITH REGARD TO A FIELD APPLICATION

In the present study Chrysoperla carnea (Steph.) (Neuroptera, Chrysopi dae)-eggs with and without stalk were compared. The eggs stem from sto ck breeds either fed with a semisynthetic diet (Bionova breed) or with aphids (Institute breed). The comparison is done with the use of the parameter hatching rate of the larvae and with parameters of the follo wing larval and pupal development. The experiments were conducted in a climatic chamber under defined conditions. The individuums of the egg and the following development stages were each kept in little petri d ishes. The results of the experiments exhibit that the hatching rate o f those larvae which originate from both variants of the Bionova breed , where the eggs were seperated from the stalk, was, clearly lower (60 % and 62 %) than that one of the other variants (78, 84 and 86 %). Th e larvae, which stem from eggs with stalk maintained at the institute developed within 19.9 days which is significantly longer than the deve lopment time of the other variants. The larvae of the same breed but d estalked required 16.9 days to reach the pupal stage. The development times of the 3 variants of the Bionova breed were 16.6, 16.1 and 15.8 days respectively. The mortality rate was highest (50 %) for those lar vae of the Bionova breed, which stem from eggs without stalk. In contr ast to this the mortality of the other variants varied between 25.6 an d 35.5 %. The duration of the pupal stage for individuals that origina te from the Institute breed was significantly longer (16.2 and 16.5 da ys) than that one for individuals of the Bionova breed 13.5 and 13.8 d ays). The other variants had no influence on the duration of the pupal stage.