In Bulgaria the plant parasitic nematode Heterodera filipjevi was firstreported in the region of Karnobat at the end of 20th century. Laboratory and field experiments on the seasonal dynamics of the species were conducted. The age structure and the population density of the nematodes were studied during the vegetation period. Delay inthe juvenile development and respectively emergency of white females was observed under both controlled and field conditions in barley for the varieties Aheloy, Veslets, and Obzor and under field conditions only in the Milena wheat variety.
The laboratory tests showed that fodder barley Aheloy was resistant and Veslets and Obzor were moderately susceptible to the nematode. The Mirjana wheat variety demonstrated high susceptibility, whiletherest of the wheat and barley varieties had intermediate position.