Marlborough wine industry hopes for sun, not more rain going into harvest
The weather is not playing ball for Marlborough grape growers, who will be praying for sun heading into harvest after more rain at the weekend.
Grapes for sparkling wine are already coming off the vines, but harvest proper does not start until later this month when sauvignon blanc grapes hit the right sugar levels.
Getting rain this late in the season increases the risk of disease, gives the canopies another growth spurt and risks delaying harvest slightly due to the dilution of sugar.
Climate Consulting climatologist Stu Powell said 26 millimetres of rain fell in the 24 hours to 8am on Sunday in central Rapaura, 22mm was recorded in Seddon, and 33mm in the Waihopai Valley.
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"But there's some nice, settled anti-cyclonic weather on the way from around Tuesday, so that'll bring some fine weather for the rest of the week," he said.
While viticulturists have brushed the rainfall off as just something that happens in an agricultural pursuit, they are unanimous about wanting a run of sun heading into harvest.
Dog Point Vineyard viticulturist Nigel Sowman said the risk of disease was lower because of the colder temperatures that accompanied the rain on Saturday.
However, any extra water at this stage of the season increased the risk, as it caused the berries to swell, potentially opening up cracks that disease could penetrate.
Sowman said botrytis was the biggest risk following rainfall. Known as 'noble rot', the fungus thrived in wet, humid conditions, causing the loss of fruit where it took hold.
Viticulturists would be out spraying against the fungus when the rain stopped. For those already harvesting, the rain might have set things back by a day or two, Sowman said.
However, a few hot, windy days and any dilution in sugar content as a result of the extra water sucked up by the vines would be reversed, and things would be back on track, he said.
Viticulture consultant Dominic Pecchenino said the other impact of rainfall was increased canopy growth, which might have to be trimmed back before harvest.
Weather during harvest last year was remarkably good, which gave wine companies a longer window to bring their grapes in, however growing conditions this year had been more challenging.
"That's just New Zealand farming, mother nature dictates more of what we do than anything else," Pecchenino said.
Data from Plant and Food showed the harvest date, when sauvignon blanc berries reached 21.5 Brix, in central Rapaura was tracking at the 10-year average of March 26.
Last season, 323,290 tonnes of grapes were harvested in Marlborough, however the industry is expecting a smaller sized harvest this year.
- The Marlborough Express