Pukekohe growers, the Balle Brothers, recently completed a successful trial growing onions on their four-hectare property without the use of the chemical Mancozeb to control downy mildew.
“We’ve proved we can do this,” says Howe Young, who manages the plot. “It was an average yielding crop, but it was quite dry and we weren’t irrigating.”
The trial forms part of the A Lighter Touch (ALT) programme which was established in May 20202 with the aim of changing the approach to food production by transitioning from agrichemical pest management to agroecological crop protection.
The Ministry for Primary Industries (MPI) has committed $11 million in funding through its Sustainable Farming Fund (SFF) with another $16 million coming from the horticulture industry.
The programme’s key partners are the Foundation for Arable Research (FAR), Zespri and Winegrowers NZ.
Chief executive of Onions NZ, James Kuperus, says the programme is very much part of the industry’s aim to be a global leader in reducing the use of harmful chemicals. “We’re never going to be the cheapest producer of onions, but we can grow a quality product sustainably,” he says.
Under the programme, trials are able to be carried out at a commercial scale so just a few growers don’t have to take the risk of becoming early adopters of new crop protection.
The plan is for four crops; onions, broccoli, barley and potatoes, to be rotated on the trial site, with onion demonstration coming into its second year. Pukekohe was chosen because of the support from local vegetable growers and wider industry, with regular field days held so the paddock can be walked and the results seen up close.
James Kuperus, left, with Pukekoke grower Howe Young, who manages the onion trial
James says downy mildew control was a problem onion growers quickly needed to adjust to. Onions NZ started providing a daily email forecast of the disease risk as part of a weather report so growers could make decisions as to whether they really needed to spray or if this long-used insurance policy wasn’t really required.
An updated model has recently been developed under ALT and growers have supported its continuation as a good investment.
The next step is to look at trial work using alternative methods to control thrips, based on research carried out by Plant & Food Research Ltd in Lincoln, Christchurch.
Antony Heywood, Vegetables New Zealand Inc chief executive, says its first trial on broccoli will look into biodiversity.
When bringing biological control agents (BCAs) into a monoculture, it is necessary to build up numbers after an initial introduction and that requires either headlands, plant borders or inter-row plants where they can multiply. They’ll then reach a level where spraying won’t be needed because they can effectively control the targeted pest.
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