Fungi invading roots of perennial ryegrass (Lolium perenne L.) in pasture

Abstract

Fungal invasion of roots in perennial ryegrass turf samples taken during Autumn, from 18 sites in New Zealand, was investigated by microscopy and plate culture isolation techniques. The most frequently encountered fungi were Phialophora radicicola Cain and sterile fungi with dark or hyaline mycelium. Other deuteromycetes, particularly Codinaea fertitis Hughes … Kendrick, Fusarium oxysporum Schlecht., Periconia macrospinosa Lefebvre … A.G. Johnson, Penicillium spp., and Trichoderma spp., basidiomycetes, and vesicular-arbuscular mycorrhizal spp., were also common. Two additional sites were sampled over a 7-month period to examine the effects of root age, season, and fungicide treatment. Fungi were not affected by season or fungicide treatment (benomyl or triadimefon plus iprodione), but brown (old) roots were colonised more by fungi than white (young) roots. Fifty of 51 isolates of fungi commonly found in ryegrass roots invaded roots of ryegrass seedlings grown axenica1ly on water agar. Gaeumannomyces graminis (Sacc.) v. Arx … Olivier caused the most conspicuous root damage, but other fungi caused sOme root-browning and cellular necrosis indicating potential pathogenicity to ryegrass roots.

Keywords:

• perennial ryegrass
• Lotium perenne
• plant pathogens
• soil fungi
• Phialophora radicicola
• Codinaea fertitis
• Fusarium oxysporum
• Periconia macrospinosa
• Trichoderma spp.
• Penicillium spp.
• vesicular-arbuscular mycorrhiza