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Fusarium mycotoxins, principally trichothecenes, occurred commonly in grain from crops in the North Island of New Zealand, but were much less common and also at the much lower levels in grains from South Island regions. The principal contaminants were trichothecenes of the nivalenol (NIV) and deoxynivalenol (DON) types. Trichothecenes derived from scirpentriol and T-2 tetraol were not common. Moniliformin occurred very rarely, while zearalenone contamination was not uncommon, but the levels were generally low. Maize kernels were commonly contaminated by moderate levels of both NIV- and DON-type trichothecenes, with levels up to 3.6 mg/kg and 11.95 mg/kg respectively recorded. The occurrence of NIV-type trichothecenes as a general contaminant in the range of 0.3-0.8 mg/kg, and frequently as the main contaminant, is unusual.

Bacterial and fungal communities in indigenous tussock grassland soils were studied at four locations, Mt Benger and Deep Stream (Otago), Cass (Canterbury) and Tukino (central North Island). Soil samples collected from inter-tussock and tussock areas were used to enumerate total culturable bacteria (colony forming units (CFU)) as well as a number of specific groups of bacteria, fungal types and diversity, and soil microbial functional diversity. Soil microbial biomass carbon (C) and nitrogen (N) as well as extractable C and N were also determined. Fungal populations were lowest at Mt Benger while fluorescent Pseudomonas was lowest at Cass. In these indigenous soils, bacterial CFU were c. 30 times lower and fungal populations c. 10 times greater than in developed New Zealand pastoral soils. CFU of bacteria in complex media (r-strategists) were similar in magnitude to bacteria growing on weak CA medium (K-strategists). The microbial biomass C in indigenous grassland soils were also significantly greater than that found in developed pastoral soils, possibly due to dominance of fungi in indigenous soils. Microbial C and N were lower in Cass and Tukino sites compared to Mt Benger and Deep Stream sites. Microbial nitrogen was also significantly greater (P < 0.001) in inter-tussock than under tussock samples. The functional diversity of soil microbes, was significantly greater (P< 0.01) in inter-tussock samples compared to tussock samples at all sites except Mt Benger. The total microbial activity, as measured by the colour development in Biolog plates (Average Well Colour Development (AWCD)), was low in Cass soil compared to others. Eighty-three types of fungi belonging to 30 genera were recovered from the four sites. The diversity of fungi found in Otago sites was greater than in the other two sites (P < 0.001). Fusarium spp. that are often common in pastoral soils were conspicuous by their rarity in indigenous soils.

The impact of two strains of the tall fescue (Festuca arundinacea) endophyte (Neotyphodium spp) (E) on the rhizoplane and rhizosphere soil microorganisms was examined at two sites (Lincoln endophytefree (E) and the endophyte strain AR501; and Aorangi E AR501 and a second strain AR542) Rhizosphere and rhizoplane populations of bacteria and fungi functional diversity root fungi and soil microbial biomass carbon and nitrogen were measured Most characteristics measured showed no differences between E and E samples indicating that the presence of endophytes had no impact on nontarget soil microorganisms At Aorangi soil microbial biomass C and N were significantly greater (Plt;005) in AR542 than E1 and AR501 soils Culturable fungal populations from both the rhizoplane and rhizosphere soil were significantly greater (Plt;005) in the E than the AR501 samples at Lincoln but not at Aorangi There were no differences in the functional diversity of rhizoplane microorganisms due to endophyte