The research on the occurrence ofCurculionoidea carried out in 1990-1995, in south-eastern Poland showed thatSitona hu mera/is Steph. was the most numerous species. Its participation among all the collected Curculionoidea was 69.4%. Other species occurring on alfalfa crops were: Hypera postica (Gyll.)- 7.7%, Si tona linea/us (L.)-5.0%, Sitona hispidulus (Fabr.)- 4.7% and Apion tenue Kirby 4.4% of the entire entomological material. In the spring, the highest numbers of adult Curculionoidea appeared in mid May and in the second half of September.

The numbers of Curculionoidea showed a growing tendency during the initial four years of alfalfa crop use for green fodder, but in the subsequent years they decreased significantly. The number of species increased with the plantation age.

Sitona hunieralis Steph. has one generation per year. Adults survive through the winter. Full life cycle from egg to adult lasts 54 days on average, including about I O days for embryo, 30 days for larval and 14 days for pupa stage.

Adults of Si tona humeralis Steph. damage leaves of alfalfa, causing bay-shaped leaf holes characteristic for the Sitona spp. The larvae damage root nodules, taproots and open the infection paths for pathogenic fungi which occur in soil and on the root surface which results in the withering of plants.