INFLUENCE OF HETERODERA SCHACHTII SCHMIDT NEMATODE ON SUGAR BEET YIELDS

In the years 2004-2010 thirty experiments were carried out in Czech sugar beet localities; these experiments allowed the comparison of yields of the variants tolerant of rhizomania and the variants tolerant of rhizomania and nematodes. The experiments were carried out on land with various degree of beet cyst eelworm (Heterodera Schachtii) contamination. On land with zero occurence of the eelworm the yield of tolerant variants was 1 % lower than the yield of intolerant variants; this changed in favour of the tolerant variants with increasing contamination. The minimum limit of harmful contamination was proposed at 3-6 live cysts in 100 g of soil. Such contamination is connected with the decrease in yield of intolerant variants by 3-5 % and it is useful that the growers react by means of agrotechnical measures.