Hail damage research to fill knowledge gap

One of New Zealand’s newest research centers is working to fill in the information gap for winegrowers hit by extreme weather events.

Bragato Research Institute has started a two year research project to work out how vineyard managers can best deal with hail storm damage on their vines.

The research has been driven by the experience of Hawkes Bay growers in October who had roughly 600 hectares of vines damaged by hail, as well as events in Central Otago and North Canterbury during November.

Project leader Len Ibbotson says there is some general information available to growers about frost effects on vines, but not on hail.

“Even with frost recovery, there is limited information available to help inform vineyard recovery strategies.”

He says for vineyard managers looking after a vineyard in an area prone to frost, it is more than likely they deal with that problem each season and have systems in place with good information on how to manage and prevent frost damage.

“For hail, there are no prevention strategies employed in New Zealand vineyards. They tend to be quite random events. There is much more chance you are going to encounter a hail event and have never dealt with it before.

“That provides motivation for me to work with growers affected, learn from them, and document their experiences.”

It’s likely that each year there will be a hail event in one of New Zealand’s wine regions, Len says, but not in same spot.

“The random nature of hail means it is important to broaden the information base available to growers, so they can react quickly and make decisions.

“It is really hard on growers and their teams when you see all the hard work of a season undone by a weather event.

“Having more information gives them a resource to help put things in perspective with what they need to do and what they might expect as an outcome.”

The research project was started after a meeting in Hawkes Bay on October 15, when Bragato Research Institute and NZ Wine Sustainability team members met with hail-affected growers and the local Rural Support Trust.

Len says the meeting was very productive with great information shared.

“This research has come from that workshop, meeting with growers, and the fantastic work the Rural Support Trust does for growers and farmers in difficult times.”

The research project will run through to August 2021.

A group of eight growers whose vineyards were affected by hail, four each in Canterbury and Hawkes Bay, will take part, recording field notes during the season, participating in interviews and by offering aggregate yield and relevant financial data for this growing season. This will enable their management decisions to be evaluated and linked to harvest outcomes.

There will also be a series of field trials in some vineyards to measure and evaluate the impact of hail damage, along with various post hail treatment options. Vines will be monitored for two seasons to capture any potential carry through of hail effects into the second season and evaluate interventions that growers may consider after hail damage.

Len says Bragato Research Institute has produced a draft scorecard for growers to help assess their vines after hail damage. When completed, it will offer growers a tool for evaluating and recording damage following a hail event, and may also help evaluate frost damage.

That draft is available now, and Len is getting feedback from winegrowers who have trialled the scorecard.

“I would like to have a final draft of that this winter, so it is ready and able to be used in the field for the next season.”

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