Studies on the relation between density of Longidorus elongatus and growth of sugar beet, with supplementary observations on Trichodorus spp

Abstract

S U M M A R YLongidorus elongatus attacks sugar beet on light sandy soils in the West Midlands. Severely damaged plants may die or recover, producing fanged roots. Up to 335 L. elongatus/zoo g of soil were found around attacked seedling plants and were often visible to the unaided eye on the roots of freshly lifted plants.Five experiments were made and regressions computed of yield of beet, total numbers of plants and numbers of normal and fanged beet on L. elongatus numbers. Between 24% and 50% of roots per IOO L. elongatus/ zoo g were killed or became fanged. Corresponding figures for loss of plant were between 7'5% and 33%. Estimated loss of yield varied between 0.8 and 7.3 tons (2.0-18.3 t/ha)/ acre/Ioo L . elongatus/200 g, the former where the potential yield was high and the latter where poor growing conditions hindered recovery.Large numbers of Trichodorus occurred in two trial sites and there is some evidence of competition between the two genera. Significant negative regressions for Trichodorus spp. were obtained in one trial suggesting a loss of 12% total and 17% normal roots per IOO Trichodorus spp./200 g.

The Effect of Plant Parasitic Nematodes, Rainfall and Other Factors on Docking Disorder of Sugar Beet

“…multiply greatly under rye-grass (Cooke and Hull, 1972) and Docking disorder caused by Longidorus spp. often occurs in sugar beet following a ley (Brown and Sykes, 1971). In the present survey most sugar-beet sites followed barley (79 per cent), as is the usual farming practice, or wheat (8 per cent) so that no reliable data were obtained on rotational effects.…”

“…may have typical stubby roots (Whitehead and Hooper, 1970) and Longidorus spp. can produce root galling (Whitehead and Hooper, 1970;Brown and Sykes, 1971). However, root symptoms are not usually characteristic in field samples and are easily confused with damage from other causes (e.g., pathogens, soil acidity, soil compaction), which often makes recognition of Docking disorder difficult; in some crops the root damage may result from both nematodes and the other factors.…”

Plant‐parasitic nematodes of potential phytosanitary importance, their main hosts and reported yield losses

“…Longidorus elongatus (de Man, 1876) Micoletzky, 1922 Pathogenic to sugarbeet, caused yield loss of up to 60% (Sigareva & Filenko, 1983). Parasitises barley, potatoes, raspberry (Sharma, 1965;Brown & Sykes, 1971. Also acts as vector for Raspberry Ringspot Virus, Tomato Black Ring Virus and Spoon Leaf Virus (Taylor, 1962(Taylor, , 1970Harrison, 1964;Taylor & Gordon, 1970).…”

Nematode Transmission of Plant Viruses

“…and with black root rot of strawberry (Perry, 1958). unthriftiness of clover (Norton, 1967) and severe decline of periwinkle (Epstein and Barker, 1966 Longidorus elongarus causes galling on strawberry roots, particularly in sandy soils (Graham and Flegg, 1968;Wyss, 1969;McElroy, 1971) and in Oregon, USA, it has been associated with severe necrosis of the roots of peppermint (Jensen, 1961); in eastern England it has been found to cause galling on the roots of barley, Brussels sprout, cabbage, carrot, celery, cress, grasses, lettuce, lucerne, radish, tomato and turnip (Whitehead and Hopper, 1970) and on light sandy soils in western England L. elongarus caused fanged roots of sugar-beet (Brown and Sykes, 1971). L. atrenuatus has been associated with root damage t o sugar-beet in soils where 'docking disorder' is prevalent (Whitehead, 1965) and in laboratory experiments it caused root galling on Fragaria vesca (Wyss, 1970a).…”