Growth of Arthrobotrys superba from a birch wood resource base into soil determined by radioactive tracing

The ability of a nematode-trapping fungus to establish in field soil is an important characteristic when considering its use as a biological control a gent. The outgrowth of the nematode-trapping fungus Arthrobotrys superba fr om wood was recorded by labelling the fungus with [C-14]3-O-methylglucose a nd [P-32]orthophosphoric acid and by using the soil sprinkling method. The fungus reached a distance of 7-8 cm during 25 days in heat-treated (60 degr ees C) soil, detected by either radioactive tracing or the soil sprinkling technique. The two labelled compounds were co-distributed at all sampling t imes (r(2) = 0.946) which indicates that the glucose pool (as methylglucose ) and phosphorus content were correlated throughout the mycelium. In natura l, non-heat-treated soil the fungus reached a distance of 1.5 cm from one d isc of birch wood after 30 days, while it reached 3.2 cm during the same pe riod when the food base was a pile of five inoculated discs. The experiment s showed, for the first time, that a nematophagous fungus, A. superba, can grow out into soil from a piece of wood and supported by nutrients transloc ated from the resource base to the edge of the mycelium. (C) 2000 Federatio n of European Microbiological Societies. Published by Elsevier Science B.V. All rights reserved.