The main goal in exploring and expanding valuable agroecosystems includes various undisputed objectives, aiming at ensuring high productivity of caryopses in cereals such an important role in the agro-industrial and food sector of the Republic of Moldova. There are losses of agricultural production because of unstable and extremely important environmental conditions, for both wheat crops and parasites, that deserve special attention and research, particularly on the parameters of the populations of parasitic nematodes, which cause severe diseases, specific to cereal plants, in the early stages of vegetation. Under the unstable pedo-climatic conditions of the Republic of Moldova, by performing biological control of nematodes, within the Parasitology and Helminthology Laboratory, at the Institute of Zoology, MSU, it has been established that the helminthic agents of cereal species trigger annually specific phyto-helminthiases and severely affect plants in the first phenological stages. The phytosanitary monitoring carried out on the parasitic nematofauna has a major theoretical-applicative significance by adapting and applying the new control measures in detecting outbreaks in plantations established with the use of new technological systems, crop rotation, modern imported varieties and hybrids. The results of the research on the diversity and structure of parasitic nematode complexes in autumn wheat agrocenoses reflect the results of the ecological, parasitic and phytosanitary impact depending on environmental conditions, crop rotation and zonal areas of the Republic of Moldova. As a result of the morpho-taxonomic analysis of biological samples of nematodes, it was found that in the wheat crop, during the spring seasons of 2021-2022, there was a higher frequency of nematodes, consisting of 18-22 species, and in the summer season – the indices were by 15-30% lower; the comparative analyses were done in different zones and in natural ecosystems, where the nematode complexes with various trophic specialization predominate, depending on environmental factors and soil structure. Thus, regarding the structure of the populations of parasitic nematodes in autumn wheat, a total number of 24 species was found, analyzing the distribution of abundance in the investigated areas where the most frequent invasive species belonged to the genera: Pratylenchus, Ditylenchus, Paratylenchus, Tylenchys, Rotylechus, Helicotylenchus, Tylenchorhynchus, Criconemoide.