Population decline of Globodera rostochiensis in Western Serbia

Abstract

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 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.

Influence of susceptible and resistant potato cultivars on the population of the potato cyst nematode Globodera rostochiensis Ro1 and on potato yields in a highly infested field in Australia

“…Resistant cultivars could feasibility accelerate the decline of PCN populations in infested land to “safe” levels, that is, where the risk of spread from a commercial crop is very low, and their use on land that is regulated as being ‘linked’ or “associated” with infested land would significantly reduce PCN risk. This is supported by the results of long‐term trials in the United Kingdom, New Zealand, the United States, Canada and Serbia, for example (Bélair et al, 2010; Brodie, 1996; Grujić & Radivojević, 2017; LaMondia & Brodie, 1986; Lane & Trudgill, 1999; Marshall, 1998), in which two to three consecutive crops of resistant cultivars in rotations, or in a monoculture, reduced nematode populations to very low or undetectable levels. Frequent cropping with H1 ‐resistant cultivars, however, risks the selection of G. pallida and other G. rostochiensis pathotypes (Whitehead & Turner, 1998), should they be present, and there is evidence of the possible development of virulent populations of G. rostochiensis in The Netherlands (den Nijs & van Heese, 2019).…”

“…Resistant cultivars could feasibility accelerate the decline of PCN populations in infested land to "safe" levels, that is, where the risk of spread from a commercial crop is very low, and their use on land that is regulated as being 'linked' or "associated" with infested land would significantly reduce PCN risk. This is supported by the results of long-term trials in the United Kingdom, New Zealand, the United States, Canada and Serbia, for example (Bélair et al, 2010;Brodie, 1996;Gruji c & Radivojevi c, 2017;LaMondia & Brodie, 1986;Lane & Trudgill, 1999;Marshall, 1998)…”

“…Reductions in G. rostochiensis population densities due to H1 ‐resistant cultivars are typically reported to be in the order of 80–90% with each crop grown (Brodie, 1996; Grujić & Radivojević, 2017; LaMondia & Brodie, 1986; Lane & Trudgill, 1999; Whitehead & Turner, 1998), although Salazar and Ritter (1992) reported a 50% reduction in field trials in Spain ( Pi 76 eggs g −1 soil). The Pi values in our trials are relatively high (>60 eggs g −1 soil) (Lane & Trudgill, 1999).…”