EFFECT OF GLOBODERA ROSTOCHIENSIS ON THE YIELD OF POTATO IN VENEZUELA

Abstract

The relationship between initial densities (Pi) of Globodera rostochiensis pathotype Ro2 and yield of the susceptible potato cultivar Andinita was investigated in 30 dm³ microplots at Cubiro, Lara State. Pi used were 0, 0.125, 0.25, 0.5, 1, 2, 4, 8, 16, 32, 64, 128 or 256 eggs/cm³ soil. Yield response to Pi fitted the model y=m+(lm)z[supPû[supT]; in which y is the relative yield, m is the minimum relative yield and Tis the tolerance limit. A tolerance limit of the potato cultivar Andinita to G. rostochiensis of 1.5 eggs/cm³ soil was derived with the model. Maximum yield suppression was 73% and occurred at Pi= 256 eggs/cm³ soil. Maximum nematode reproduction was 20-fold and occurred at Pi= 0.25 eggs/cm³ soil. Nematode equilibrium density was 40 eggs/cm³ soil.