Population Decline of Globodera Rostochiensis in Western Serbia

Annual decline rates of potato cyst nematode (PCN) populations have been extensively studied. They vary considerably due to many factors, including potato cultivar, initial PCN density and climatic factors. Information is needed on PCN decline in potato fields in the specific conditions of Western Serbia, which is the centre for most of the local potato production, especially seed potato. We investigated the decline of Globodera rostochiensis over 1 or 2 years under the influence of PCN-resistant potato cv. Agria in the field and microplots. Decline was compared with fallow in Ponikve, near the original record of G. rostochiensis. Population decline in the field after cv. Agria was approximately 80%. In two parts of the field where potato cv. Agria was cropped once or twice with fallow before and after, the viable PCN population declined over 9 years to about 1% of initial Pi values. In a third part of the field, left fallow for 9 years, 15% of the initial population was still viable, after an annual decline rate of 9.4%. The influence of volunteer potatoes on maintaining PCN populations was also examined. In the microplots, with a higher density of volunteers compared to the field, PCN decline under resistant potato cv. Agria was 70%. At crop harvest a new generation was recorded, suggesting its possible formation on susceptible volunteer potato. The full cysts represented 1% of all cysts examined and 13% of total second-stage juveniles found in the samples. The information will be useful for improvement of management procedures.