Squash ban quashed with help from fungal research

Squash ban quashed with help from fungal research

Research on a troublesome fungus has led to the removal of a trade barrier that was costing buttercup squash growers a million dollars a year in lost exports.

South Korea has been destroying or re-shipping New Zealand buttercup squash (kabocha), because of a fungus associated with the squash that was believed to threaten their rice crop.

Potatoes from the USA and Australia were also destroyed when the same fungus was detected. The fungus was believed to be Verticillium tenerum, which was classed as a pathogen by the Korean National Plant Quarantine Service.

The New Zealand Kabocha Council commissioned Landcare Research to review the naming, biology and distribution of this fungus, in the hope of convincing South Korean authorities it was not a quarantine pest.

Landcare Research mycologist (fungal scientist) Dr Eric McKenzie says the fungus in question is quite harmless.

"While some Verticillium fungi are serious plant parasites, others in the group merely help to rot dead material. These fungi are not pathogenic, and do not damage rice.

"Dr McKenzie also uncovered a complicated case of mistaken identity. "There has been extensive confusion over whether this fungus belonged to a Verticillium-like group called Nectria, but research in the Netherlands has found this is not the case. Also, the fungus is not actually V. tenerum at all. It is in fact V. luteo-album, which is equally harmless.

"Dr McKenzie says he does a good deal of research on fungi for quarantine purposes, particularly for Pacific Island nations, but does not always get to hear how his findings are used."It's wonderful to think that a week's work on my part means a million dollars a year to the buttercup squash industry.

"The New Zealand Kabocha Council represents New Zealand's 140 buttercup squash growers, who export about 90,000 tonnes of product annually, mainly to Japan. The Council's manager, Ross Johnson, says Dr McKenzie's work helped achieve "a real breakthrough".

"It enabled the Ministry of Agriculture and Forestry to prove to the South Koreans that the concerns were based on the wrong 'pest'. It brings to an end a problem that has persisted for several years. "We expect to see an increase in exports to South Korea, as exporters will no longer be wondering whether shipments will be stopped at the border.

"ENDS

Build me up, Buttercup: The buttercup squash industry can expect to boost export earnings by $1 million a year, thanks to a science review by Landcare Research. Colour digital image supplied by Vegfed.

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