Fungi are perhaps better known for the damage they do, rather than for their usefulness. They are responsible for the deterioration of textiles and food substances stored under damp conditions, as well as for the rot of harvested fruit and vegetables, sap stain in milled timber, and decay of timber in damp situations. Parasitic fungi are one of the principal agents of diseases in plants. In New Zealand in some seasons considerable losses are caused by diseases such as blight on potatoes and tomatoes, brown rot on stone fruit, and bitter rot on apples; rust and smut of grass and cereal crops are also common. Thus rigid spray programmes must be maintained to prevent serious crop losses, and resistant plant varieties be developed. Mushroom poisoning is not unknown in New Zealand, but in no case has the guilty species been identified. As little is known about mushrooms and toadstools common in our native forests, it is dangerous to eat fungi other than those known to be edible in European countries. The lethal Amanita phalloides has been collected in an Auckland park. Elsdon Best, in Forest lore of the Maori, notes that the Maori did eat some fungi, probably about 12 species, but only in times when food was scarce. They recognised that some species were poisonous. The common Jew's-ear fungus (Auricularia polytricha), which was at one time exported in quantity to the east, was eaten but not really liked, and was usually cooked with a green vegetable.

A cattle disease known as “staggers”, due to ergot poisoning, is not uncommon in North Auckland and is caused by seed heads of the grass Paspalum becoming heavily infected with the ergot fungus Claviceps paspali. “Facial eczema” in sheep and cattle has been shown to be due to a toxin in a mould Pithomyces chartarum, which grows on debris in pasture during humid conditions.

Studies in geographic distribution of fungi show that many species, especially among saprophytes, are common throughout the world. Fungal spores are so small that they are easily distributed by wind and in rain droplets. Natural transport, such as prevailing air currents, play an important part in spreading some crop disease epidemics. The most important factors are temperature and a suitable substrate. Pithomyces chartarum, the black mould fungus responsible for “facial eczema” in Australia, occurs in most warm temperate countries and only in the north of New Zealand. In this case temperature limits its distribution. Many species which parasitise leaves of seed plants are specific to a single host species, so that distribution is limited by the spread of the host. For example, 77 per cent of the rust fungi are found only in New Zealand. Cordyceps robertsii, the vegetable caterpillar parasitising a moth larva belonging to Oxycanus, occurs only in Australia and New Zealand. High mountain ranges and oceans also makes natural barriers to distribution, and even among saprophytic species there are in New Zealand a number which are endemic, e.g., the small spiney puff ball, Lycoperdon compactum, occurs only in forests in New Zealand. Similarly, the purple Secotium porphyreum occurs only in New Zealand Nothofagus forests.

Since the publication of a list of fungi in Hooker'sFlora novae-zealandiae (1855) and Hooker's Handbook (1867), where some 200 species were described, no catalogue of New Zealand fungi has been made. In Cooke's Australian fungi (1892) New Zealand species are referred to only when they occur in both countries. Records and observations on New Zealand fungi have, however, been published in periodicals, both in New Zealand and overseas, and the number of fungi reported to be present must now be well over 1,200 species belonging to approximately 240 genera. As fungi play an important role in the diseases of plants, studies have been directed into these groups and some 700 pathogenic species have been described. Few have been listed among the saprophytic species, and in large groups, such as mushrooms and toadstools, few species have been described, while for most groups of smaller fungi there are, as yet, no records.

by Joan Marjorie Dingley, M.SC., Plant Diseases Division, Department of Scientific and Industrial Research, Auckland.

• The Biology of Fungi, Ingold, C. T. (1961)
• D.S.I.R. Plant Diseases Division Bulletin, No. 72–82 (1947–49), “The Polyporaceae of New Zealand”, Cunningham, G. H.
• Rust Fungi of New Zealand, Cunningham, G. H. (1931)
• Gasteromycetes of Australia and New Zealand, Cunningham, G. H. (1942)
• D.S.I.R. Bulletin, No. 145 (1963), “The Theliphoraceae of Australia and New Zealand”, Cunningham, G. H.
• Forest Fungi, Lancaster, M. E. (1955).