A. BÂRBULESCU, C. POPOV, I. SABAU
Research Institute for Cereals and Industrial Crops, 8264 Fundulea, Nicolae Titulescu str., no. 1, District Calarasi, Romania, e-mail: fundulea@ns.ricic.ro

European Corn Borer (EC13) is one of the most important pests of maize in Romania, having an unique significant generation per year. This insect can cause high yield losses, by its attack on the late whorl stage of leaves, and especially on panicle, stem and ear. Maize hybrids resistant to ECB being of economic interest, as the best method for prevention of the pest attack, mainly in USA, an experiment regarding the behaviour of a Monsanto genetically modified maize hybrid (Dekalb 512 Bt) in Romanian conditions was carried out.
The experiment was performed under artificial infestation with egg-masses, usually 20 egg-masses/plant, at different vegetation stages of plants, and different climatic conditions, which generally correspond to the female egg-laying period under natural conditions. Beside the Dekalb 512 Bt hybrid two well-known Romanian hybrids, Fundulea 376 and 01t, characterized by a smaller ECB attack have been used. Separately, Dekalb 512 Bt hybrid was compared with a Romanian tolerant hybrid I-ISF 1071-96 and with a susceptible one HS17 1147-96. The attack estimation was done by spliting plants in autumn, during harvest, and the registration of both the lenght of tunnels bored in plants (cm), and the alive and dead larvae number and pupae exuviae/plant.
The results showed that, although the ECB attack was diminished because of unfavourable climatic conditions for pest during the experimental period, the registered attack values gave the possibility of a categorical differentiation regarding the tested hybrids reaction. The Dekalb 512 Bt hybrid has a very good resistance to the ECB attack in all the cases, irrespective of the vegetation stages of plants, the attack values having sporadic traces. The Dekalb 512 Bt hybrid resistance was satisfying for all infestated vegetation stages, including panicle appearance, which correspond with the evolution period of the single generation with economic importance in Romania. Although the Romanian experimental hybrid HS17 1071-96 had a decreased attack level, the genetically modified hybrid Dekalb 512 Bt was not practically attacked by EC13.