The monitoring of the species with harmful potential is very important because it allows to acknowledge the level of development of the germs aand of the pests and the understanding of biological cycles of the pests allows the proper intervention in the most adequate moments for stopping or limiting the destructive effects of pests on the agricultural crops. Studiile şi practica referitoare la dăunătorii culturilor agricole şi combaterea acestora au demonstrat că dăunătorii autohtoni, care sunt foarte bine adaptaţi condiţiilor climatice nu pot fi eradicaţi şi de aceea controlul dăunătorilor se referă în mod deosebit la monitorizarea acestora şi menţinerea lor sub limita pragului economic de dăunare. The study and the experience regarding the pests of agricultural crops and their control have proved that the local pests, which are very well adapted to climate conditions can’t be eradicated and this is the reason why the pests’ control refers especially to their monitoring and maintaining the number of individuals under the limit of economical threshold of injury. The study on the invertebrates’ communities in some biological cultures in SCDL Bacau, performed during a period of four months, June – September 2007, has aimed at monitoring the pests and the useful fauna for applying some preventive and curative measures of limiting the pests’ attacks. In the four studied cultures there were identified 35 taxons of invertebrates belonging to different systematic groups (2242 individuals). In the biological agriculture, preventive and curative measures of limiting the pests’ attacks are adopted, especially in the case of vegetable plants, measures that, besides the improvement of the agricultural work, seek to identify the useful fauna (animal feeders) and to protect and encourage their breeding. Within the study we performed, the greatest percentage of useful fauna registered during the whole period of research was in the celery culture, followed by the ones measured in the dill, parsley and violet tomatoes cultures.