Sugar beet nematode Heterodera schachtii distribution and harmfulness in Ukraine
Aim. To determine the distribution of sugar beet cyst nematode Heterodera schachtii in Ukraine, to defi ne its population density in soil, the degree of damage and the effi ciency of control measures. Methods. Field survey for soil samples, cyst extraction by fl otation and sieving method, light microscopy. Results. The examination of 12,130 ha of agricultural fi elds in six regions of Ukraine, conducted in 2010–2015, recorded the sugar beet cyst nematode to occur in fi ve of them (Kyiv, Chernihiv, Cherkasy, Khmelnytsky, and Vinnytsia), at a total area of 2,572 ha. Taking into consideration the results of previous nematological surveys, the presence of sugar beet cyst nematode has now been documented for 18 regions of Ukraine. In most regions H. schachtii was present in 10–11 % of the examined sugar and seed producing farms with nematode population densities reaching up to 142,000 eggs and juveniles in 100 cc of soil (710-fold above the economic threshold). Conclusions. The main reasons for this wide distribution of H. schachtii in Ukraine are seen in the negligence of prevention measures, unavailability of documented data on its occurrence (missing surveys), crop rotations with over 20 % of host plants, and unavailability of effi cient nematicides and domestic nematode-resistant sugar beet cultivars.