Actinomycetes and bacteria, but not fungi, increase rapidly in numbers during the passage of food through the worm gut. Enzymes produced by the worm rather than micro-organisms seem to be the main agents digesting cellulose and chitin. The rate that material moves through the intestine depends on whether the animal is feeding; food takes about 20 hr. to pass, but when burrows are being formed material passes in about 12 hr.

SUMMARYMicrobiological, physical and chemical changes were followed in worm casts ageing in the field. Filamentous fungi and yeasts increased in number rapidly after the cast was produced, but not bacteria or actinomycetes which were initially numerous. Measurements of hyphal length confirmed the increased growth of fungi. Ageing casts showed a declining respiratory activity, possibly because the bacteria formed resting stages. Aggregate stability increased rapidly as casts age, probably due to increasing amounts of fungal hyphae. Polysaccharide content of casts was much greater than that of soil, but did not vary with changes in stability. Total and mineral nitrogen levels of casts were greater than those of soil; the major part of the inorganic nitrogen occurred as ammonia which was rapidly converted to nitrate.

Moulds demonstrable by routine culture techniques on leaves of pasture plants were examined to assess the incidence of toxinogenic groups. Perennial ryegrass, white clover, and litter from ryegrassdominant pasture were collected regularly for 2 years from sites in the Waikatc basin. Numbers of moulds were highest on litter, lower on ryegrass leaves, and lowest on clover. Numbers were greater in paddocks being grazed than in those from which stock were excluded. The most commonly recovered groups were, in approximate order of frequency, pycnidial forms; Cephalosporium spp.; Cladosporium herbarum; Fusarium spp., in particular F. nivale; Colletotrichum spp.; Rhyncosporium spp.; Verticillium spp.; Myrothecium spp.; Pithomyces chartarum; and Metarrhizium aniso pliae. F. nivale and two groups of Cephalosporium were virtually restricted to ryegrass leaves and litter, and Verticillium spp. and M. anisopliae to clover leaves; other groups were common to all types of substrate. The litter flora was qualitatively like that of green ryegrass leaves; that from some mixed pasture samples from Gisborne was similar to that from Waikato material.Almost all moulds isolated belonged to taxa known to have some pathogenicity to plants; they did not appear to be true members of the phyllosphere. No evidence was found for succession of populations, each group apparently varying independently of the others. P. chartarum, F. nivale, and Myrotheciurn spp. were the most commonly occurring groups known to be toxic to mammals. P. chartarum made up about 1% of the moulds isolated during the first half of 1968, when there was a widespread outbreak of facial eczema.

The source and nature of yeasts responsible for the natural fermentation of grape must in New Zealand have been examined. Kloeckera apicuiata was the dominant species during the first stage of fermentation. but was later replaced by Saccharomyces cerevisiae, with lesser proportions of Saccharomyces chevalieri and Saccharomyces rosei. No fermenting yeasts were recovered from green grapes but most isolates from ripe grapes were of K. apiculata and S. cerevisiae. It was thought that the source of the fermenting species was the winery itself and previous season's pomace, in which they were found to be common; they were very rare in vineyard soil and were not recovered from fragments of bark and twigs of vines collected in winter. The vector by which fermenting species reached the ripening grapes was probably insects.

Thiabendazole and eight other fungicides were applied to pasture by a number of different methods and the effect on numbers of Pithornyces chartarum spores examined. Thiabendazole and benornyl sprayed at rates of 2-32 ozjacre reduced spore numbers during periods of accelerated production by 40-90% for 6 weeks. Application rate within this range had little effect on the length of time for which the fungicides were effective. Cercobin (NF44) at 4 oz gave control equal to that of thiabendazole at 4 oz, but 32 oz of Phenzidol and 16 oz of EL273 were needed to give the same measure of control. Fuberidazol, DUI3710, and Busan 72 at rates up to 16 oz and Euparen at 160 oz did not control spore numbers. The use of different formulations of thiabendazole did not affect results. Ultra-law-volume formulation of Fuberidazol and the addition of wetting agent to Euparen did not improve the performance of either of these materials. Thiabendazole applied aerially gave the same control as the hand-sprayed fungicide. Simulated rain, applied at rates of 1-2 in. within 3 days of spraying of 4 oz thiabendazole, removed all fungicidal effect, but control remained when only t in. of rain was applied. Early spraying of thiabendazole in November, December, or January affected spore numbers only for the 6-week period of effectiveness of the fungicide; subsequent spore counts on sprayed plots were equal to those on unsprayed controls.