Because almost all New Zealand native plants form arbuscular mycorrhizas there are very large areas free of ectomycorrhizal fungi that might compete with the Périgord black truffle. This made it unacceptable to supply growers with truffle infected plants contaminated with other ectomycorrhizal fungi. This required new seedling production methodologies.
The first truffières
Prospective growers of Périgord black truffle infected plants were advised that the ideal conditions were:
• Warm summers and cool winters,
• A free draining, high pH (above 7.5 with an optimum of 7.9), well aerated soil, about 400 mm deep overlying a limestone base e.g. rendzina and related soils,
• Irrigation water,
• The absence of other trees that may have competing fungi on their roots.
However, many people who expressed an interest in growing the Périgord black truffle owned land with naturally acidic soils. After testing their soils these people were given an estimate of how much lime would need to be applied to their soil to raise the pH to the optimum of 7.9. The soils were then retested at intervals to determine when sufficient lime had been applied. Overall not less than 2 tonnes of lime needed to be applied to raise the pH in the topsoil by 0.1 pH unit. By 1990 eleven Périgord black truffle truffières had been established between the Bay of Plenty in the North Island (38°S) and North Otago (45°S) in the South Island.
The first Southern Hemisphere Périgord black truffle truffles were found on 29 July 1993, exactly five years after planting, in a truffière near Gisborne on the east coast of the North Island (39°S). The first commercial harvest was made in June 1997.
Most of New Zealand’s productive truffières have been established on naturally acidic soils. The highest New Zealand yield has been from a truffière in the Bay of Plenty (38°S) that had been established in 1988 on a heavily limed volcanic ash soil with a natural pH of 6.2. Because New Zealand growers are producing truffles counter season to France, Italy and Spain and sell directly to the consumer, they are receiving around twice the price premium quality Périgord black truffles sell for in Europe.
The first bianchetto truffles to be harvested in the Southern Hemisphere were found on 7 July 2006 under a three year old Pinus pinea (stone pine) plantation near Christchurch (43.5°S). The first commercial harvest began in another truffière in April 2008.
Click here to download an English translation of a paper on the cultivation of the Périgord black truffle in New Zealand.