The effect of beet cyst nematode, Heterodera schachtii, on the yield of sugar beet in organic soils

Abstract

SummaryIn ten experiments on commercial sugar‐beet crops grown on organic soils in 1984–86, a Genstat programme was used to examine the relationship between the initial population of Heterodera schachtii and sugar‐beet root yield using the equationY = Ymin + (Ymax ‐ Ymin) Zpi‐TFixing T = 200 eggs + juveniles 100 g‐1 soil and ZT= 0.95, estimated values of Ymax varied from 49.2–67.1 t ha‐1 (129– 155% of the national average root yield for the years in which the experiments were carried out) and estimates of Ymin varied from 14.5–53.9 t ha‐1 (27–94% of Ymax). The estimated average root yield loss caused by the nematode was 6.95 t ha‐1.