Pruning Priorities

Vaughn Wolland from Berakah Vineyard Management at the mechanical pruning module

Knowledge sharing at Winter Field Day

SOPHIE PREECE

WITH NEARLY 30,000 hectares of Marlborough vines to be pruned this winter, grapegrowers should be strategic about when and how they work on individual sites. “If you have got hillsides, if you have got areas that are tricky to get done, do those first,” Dog Point Vineyards viticulturist and Marlborough Winegrowers board member Nigel Sowman told attendees at the Wine Marlborough Winter Field Day last month. “Get them out of the way while you can. It really makes a big difference at the end of the year.”

Nigel reflected on the 2022 season, in which some growers were unable to prune before budburst, due to 30 days of torrential rain and an inexperienced Recognised Seasonal Employer (RSE) scheme workforce, exacerbated by an additional 450ha of vineyard area. With a similar growth in plantings this year, the field day offered an excellent opportunity to grow understanding, he said. “This whole industry was built on sharing knowledge. We have people who know a lot willing to give up their time and share that knowledge for the best way forward. Everyone will learn something.”

Whitehaven viticulturist Jess Wilson and Plant & Food Research scientist Dion Mundy were among those sharing their knowledge, with a module on measuring and mitigating grapevine trunk disease (GTD) in Marlborough vineyards. Both of them are bemused at the number of companies not disposing of dead vines, protecting new vines, monitoring the incidence of trunk disease in every block, and painting or spraying pruning wounds. “And don’t prune in the rain,” said Jess, amazed at how many people ignored that advice. In the wet and labour-short 2022 winter season, growers may have felt pressured to prune in the rain, regardless of the risk of spreading trunk disease, she said. “This year we’re not in that space, but the other day when it was raining, the number of crews out there was ridiculous.”

Jess and Dion echoed Nigel’s advice to prioritise blocks, leaving any vineyards flagged for replanting low on the list. If people are under pruning pressure, they should only consider those compromised blocks for wet pruning days, Jess said. “But don’t work on your good blocks in the rain.” Dion would be happy if growers would follow his simple list – reworking, wound protection, remove deadwood, monitor GTD, and don’t prune in the rain. Like Jess, he suggests growers consider which vineyards are due for a replant, perhaps because of virus, and put them lower on the pruning list. “Don’t make them a priority.”

Jeff Sinnott and Matt Gallop from Constellation Brands were also at the field day to talk trunk disease, with a module on replanting plans. Constellation has adopted a model where they can assess a block and discuss whether it warrants a full redevelopment, or go with a “grandad’s axe approach”, in which different parts are replaced at different times as necessary, said Matt. “It means looking at how we are dealing with the disease within the block and, if we are going to be planting new vines in it, how do we stop that new plant contracting that disease?” Constellation’s battle against trunk disease sees them undertake two rounds of wound protection through winter, with a spray after the Klima cut, then a paint after wrapping. Jeff said it was key to measure change, in order to consider the best course of action. There’s no hard and fast rule, as each vineyard has a unique set of situations, he added. “There are all sorts of decisions you make that all have different permutations.”

Logie MacKenzie and Vaughn Wolland from Berakah Vineyard Management spoke about mechanical pruning options at the field day, while Tanya Pouwhare, chief executive of New Zealand Ethical Employers, spoke about the continuing challenges faced by contract labour suppliers, including the need for 2,500 additional beds for Recognised Seasonal Employer scheme workers over the next five years. Viticulturist Mark Allen and Dr Carmo Vasconcelos, from Bragato Research Institute, spoke to attendees about alternative pruning methods, including new research around long spur pruning, while the final module canvassed freshwater farm plans.