Nationwide survey of pests and diseases of cereal and grass seed crops in New Zealand. 2. Fungi and bacteria

Abstract

A national survey of seed crops was conducted by the New Zealand Plant Protection Centre (NZPPC) from October 1995 to February 1996. Approximately 85,000 plants were inspected at 332 sites in the main cereal growing areas of New Zealand. One hundred and eighty new host/fungal associations were recorded for barley, brome, oat, ryecorn, ryegrass and wheat. Of these 26 were primary pathogens able to cause plant damage. The most common new associations were of fungi causing root rot problems, especially Phytophthora, Pythium and Fusarium species. The fungus, Ceratocystis paradoxa was found for the first time in New Zealand at two sites in Dunedin where it caused leaf spotting on wheat. Of the fungi and bacteria previously known to occur on cereals and grasses in New Zealand, Fusarium species were the most commonly observed, primarily associated with foot rot. A number of fungi and bacteria previously recorded on these hosts in New Zealand, were not detected during this survey. New Zealand’s freedom from a range of important exotic fungi and bacteria was confirmed.