Relationship between potato cyst nematodes and their principal host. II. Evaluation of mathematical descriptors relating potato yield and nematode density

Abstract

SummaryTo describe the relationship between nematode density and yield, four equations of increasing complexity are found in the literature. They concern a linear regression curve, a log linear regression curve, a regression curve based on an exponential relation and an inverse linear regression curve. The yield to PCN density responses of these equations are shown on a linear and on a logarithmic scale. Considerable differences are shown in the way they respond to the same data. None of these equations is able to explain or forecast yield decrease caused by potato cyst nematodes,