INFESTATION OF SHEEP DUNG BY NEMATOPHAGOUS FUNGI AND IMPLICATIONS FORTHE CONTROL OF FREE-LIVING STAGES OF GASTROINTESTINAL NEMATODES

A field trial was conducted to assess the rate at which dung becomes i nfested by fungi which parasitise nematodes (nematophagous fungi) afte r deposition. Sheep dung was placed on field plots of bare ground, rye grass (Lolium perenne), browntop (Agrostis capillaris) and white clove r (Trifolium repens) in summer (February) and autumn (April), and subs amples were examined at intervals for the presence of nematophagous fu ngi. Nematophagous fungi occurred in 71% of 129 samples recovered in F ebruary and 57% of 58 samples recovered in April. Arthrobotrys oligosp ora, Monacrosporium candidum and Nematoctonus spp. were the most frequ ently isolated nematode-trapping fungi in both seasons. The endoparasi tic nematophagous fungus Harposporium leptospira also occurred frequen tly in dung deposited in February, but not April. Fungi entered dung q uickly, with 83% and 58% of dung samples containing nematophagous fung i at 3 days after deposition in February and April, respectively. The percentage of dung infested by nematophagous fungi on plots of bare gr ound, ryegrass, white clover and browntop was 76%, 75%, 61% and 55%, r espectively. Results suggest that a number of species of nematophagous fungi are able to enter dung soon after deposition on a variety of ty pes of ground cover. (C) 1997 Elsevier Science B.V.