The relationship between numbers of Heterodera schachtii and sugar beet yields on a mineral soil, 1978‐81

Abstract

SUMMARYIn a 4‐yr field experiment on a mineral soil infested with beet cyst nematode (Heterodera schachtii) the relationship between root yield of sugar beet (y) and initial population of H. schachtii (Pi) fitted the equation: y=y min +(y max ‐ y min) ZPi‐T y min = 7·7 t/ha, y max = 39·4 t/ha, 2 = 0·99938 and T= 0 eggs/100 g soil. From this information and that obtained during a recent survey of 2766 beet fields, the total national root yield loss caused by H. schachtii was estimated as approximately 10 000 t/annum on mineral soils and (assuming a similar yield loss relationship on all soil types) 30 000 t/annum on organic soils.No consistent differences in efficiency of extracting cysts were found between the Fenwick Can and the flotation column. A bioassay technique was as effective as cyst extraction techniques in identifying infested soils.

Relationship between physiological response of French beans of different age to Meloidogyne incognita and subsequent yield loss

“…Most assessments of nematode-induced loss (e.g. Paruthi & Bhatti, 1981;Kinloch, 1982;Cooke, 1984) do not include a study ofthe physiological basis for loss of yield. It has been known for many years that nematodes affect younger plants more than older plants (Seinhorst, 1961), but this response has not been related to the host's physiology to show how flower or seed production is influenced by a particular duration and intensity of nematode infection.…”

Evaluating resistant brassica trap crops to manage Heterodera schachtii (Schmidt) infestations in eastern England

“…Population reductions, as a result of growing trap crops, may be useful only if they lead to increased yield in subsequent crops and can be accommodated within the farming rotation. Cooke stated clearly that a trap crop should meet three criteria before being suitable for commercial use, and these stand true today. First, it should stimulate egg hatch, which we have shown to be the case with at least two of the varieties used.…”

The effect of resistant cultivars of catch crops on the hatching of Heterodera schachtii

“…Heterodera schachtii Schmidt is an important nematode pest of sugar beet capable of causing severe yield losses (Cooke, 1984). In England it is well established in the organic soils of East Anglia, some adjacent mineral soils and other small, localised areas, especially where brassicas are grown frequently (Southey et al, 1982).…”