Successive to the researches performed in the experimental field from S.C. Agrogil (Sagu, Arad county), during 2006-2007, where we cultivated 8 maize hybrids, belonging to various maturity groups (extra-early, early, mid-early, mid-late), of American origin (Pioneer Al Dupont Company), we have noticed the following aspects related to their yields: - the productive amplitude of the 8 Pioneer maize hybrids, studied in the Arad region, was between 4692 kg/ha (PR 39D81) and 7459 kg/ha, achieved by the control hybrid PR 37D25; - the fungi within the maize pathosystems – Helminthosporium turcicum, Fusarium roseum and Ustilago zeae, with their parasitical effect, have determined a decrease of the average hybrid yield with 1155 kg/ha; - the new pest Diabrotica was involved, through its rhyzo-, philo- and stigmatrophic actions, with a yield decrease of 2161 kg/ha. The reduction of maize hybrid yields is due to some intrinsic (internal) and extrinsic (external) factors. The intrinsic factors belongs to the maize hybrids and it is about a lower activity of the genes involved in production and the lack of genes generating resistance to diseases and to the new pest Diabrotica. The extrinsic factors include soil, as an edaphic factor, with a low nutritive content (absence of fertilization) and the insufficient release of absorption elements, monocrop and the parasitical factor.

Zea mays; pathosystem; production; hybrid; Diabrotica

Presentation: oral