Occurrence, morphological characteristics and ribotyping of New Zealand isolates of Duddingtonia flagrans, a candidate for biocontrol of animal parasitic nematodes

Abstract

The nematophagous fungus Duddingtonia flagrans has shown potential for biological control of nematode parasites of livestock in several countries. A survey for the presence of D. flagrans in New Zealand was undertaken in 1997–98 on 24 farm, research, and domestic properties in the southern North Island. The nematophagous fungi found on isolation plates included species of Arthrobotrys, Dactylellina, Nematoctonus, Harposporium, and Duddingtonia. Isolates that produced the three‐dimensional nets and abundant chlamydospores, characteristic of D. flagrans, were detected in 6 of 205 samples examined. The fungus was obtained from a variety of substrates such as cattle dung, horse dung, seepage from a silage pit, and decomposing lawn clippings. Morphological characteristics, and the sequences of ITS/5.8 region of ribosomal DNA, were very similar to those published for D. flagrans. The fungus was re‐isolated from the faeces of lambs 16–40 h after they had been dosed orally with chlamydospores, indicating survival of gut passage.

Key words:

• gastro‐intestinal nematodes
• sheep
• parasites
• nematophagous fungi
• Duddingtonia flagrans
• biological control