Alexandru BARBULESCU
Research Institute for Cereals and Industrial Crops Fundulea
8264 Fundulea, District Calarasi, Romania

Maize resistance to the attack of the European Corn Borer is an outstanding objective of maize breeders, imposing an approach of research on its rearing on artificial diets. This paper presents a series of data on the continuous rearing of ECB on artificial diet for several successive generations. During 1978-1998 a different number of colonies derivated from the natural population were created, one in a certain experimental year, in order to pursuit simultaneously different generations reared onartificial diet. The first colony was founded in 1978 and the last one in 1997. Periodically, tests with these colonies were carried out, and the nutritive value of the diet was scored by the number of pupae obtained from a rearing-box, duration of larval and pupal stages, and the number of egg-masses laid by a female. To pursuit behavior of various O. nubilalis generations reared in the same time periods, in separate trials fecundity and adult life span were recorded. These parameters were noted separately, for each colony and generation.

It was found that ECB reared on artificial diet reached at the end of 1998, according to the experimental colony, the 248-th generation in the case of the colony started in 1979, the 36-th generation for the colony founded in 1996 and the 22-nd generation of the colony set up in 1997. The number of pupae per rearing-box, duration of development (days) of larvae and pupae, as well as numbers of egg-masses per female have been not influenced by the number of generation to which the insect reared on artificial diet in a steady flow belonged. Fecundity and life span of adults reared on the same diet were similar.

The diet used for rearing the ECB demonstrated a suitable nutritive value. The insect reared in successive generations behaved similarly, irrespective of the number of generation they belonged to.
The experimental conditions significantly influenced the mass rearing of this insect on artificial diet.