Íslenskar landbúnaðarrannsóknir - 01.09.1971, Síða 34

32 ÍSLENZKAR LANDBTJNAÐARRANNSÓKNIR
S U M M A R Y
OBSER VA TIONS ON WINTER DAMAGES CAUSEl) BY
LOW-TEMPERATURE FUNGI IN ICELANDIC HAYFIELDS
Bjarni E. Guðleifsson,
Agricultural Research Institute, Reykjavik, Iceland.
In 1968 and 1969 reasearch was períormed on the role played by low-tempera-
tnre parasitic fungi in winter damages of Icelandic permanent hayfields. During
1968 93 samples of dead grasses were taken frorn damaged hayfields widely
spread over North-Iceland, and these examined uncler the microscope for the
prescence of conidia and sclerotia from low-temperature parasitic fungi. Also
the fungicid PCNB was sprayed at 15 sites in South- and North-Iceland. The
chemical was applied in the autumn of 1968 and the extent of winter damages
observed in the following year.
During both years considerable winter damages occured at the sites of ob-
servations. In 1968 hayfields in their first year of establishment were less
damaged than older fields while the opposite was the case in 1969. This coulcl
indicate that fungal darnage was more prevalent in 1969. The spraying experi-
rnents, however, did not reveal that fungi played anv part in winter damages
in 1969, and neither conidia nor sclerotia from low-temperature parasitic fungi
were found in the samples of damaged grass taken in 1968. Tlie presence of
these fungi remains to be proved in Iceland, and it is suggested that Fusarium
nivale seems the most likely one to be present. Some evidence indicates that
dessication was the rnain cause of the winterdamages in 1969 while continuous
ice sheets seemed to be to blarne in 1968.