Managing suckers that appear at the base of grape vines during spring is essential for the health of the plant through the season. Agronomist, Katelyn Keller, of Farmers Johns, in the Barossa region of South Australia, said suckers start to grow out of the trunk and root of the grape vine in October and November each year. As well as being unsightly, she said suckers also utilise nutrients, water and could be a vector for disease. During the season suckers were generally out of the spray zone of any fungicide products aiming at the canopy, so they would often get a sub-lethal or nil dose. “The little things start to add up and make it a lot more difficult for management,” Katelyn said. “To nip them in the bud before they become an issue is what we are aiming at.”
She said, in the past, vineyards brought in gangs of people to manually remove the suckers. “I’ve had that job before and it’s not fun. It feels never-ending.” “Labour's always a tricky one for growers. It’s hard to get reliable people and when you can get that labour, it doesn't quite coincide with when you’ve got those suckers. Labour cost is always going up, and growers need to be as efficient as possible.” “Rising costs of production is an ever-increasing thing on growers’ minds. Just having those extra passes coming through adds the costs up quickly.”
Katelyn said the preferred method of sucker control in the Barossa region was Spotlight Plus herbicide from FMC. Spotlight Plus is an herbicide which can be applied directly to suckers and works by controlling the green areas targeted without affecting other parts of the vine. The active constituent is not translocated through the plant so it will not affect roots or unsprayed leaves. “You can sit on the tractor and use it for sucker control,” Katelyn said. “Growers have lots of things to do in a vineyard. It is a never-ending job. Having the confidence that Spotlight is going to do its job is excellent.
She said growers would spot spray by hand to tidy up or use a spray cart with dedicated nozzles aimed at the base of the vines where the suckers are present. “With good coverage it is safe well into the growing season, which is one big thing that growers are always mindful of. That’s why I always like to have it as a staple for growers in the program.” Katelyn said growers would wait until suckers were at least 10cm in length and apply Spotlight to maximise control. “You see a really quick burn off. You don't want it to be taking weeks, with the suckers still being able to pull resources knowing that it's not actually going into the plant.” “Thirty centimetres is probably the maximum you'd probably go so as to get that full control. Spotlight works really well and it's nice to recommend it to growers. It’s a really good staple to have in the shed, knowing that it's not going to have adverse effects on the vine as it's growing and developing the canopy.”
Spotlight Plus was also used in between the rows as a spike in some of the herbicide runs. “It has good compatibility and works on those really hard to control weeds like your marshmallow and stinging nettle, that are always coming up every year.” “You can use it during winter or throughout the whole growing season too. Spotlight is one of the more popular options that we've got.”
The Barossa region is renowned for its high-quality wines with varieties such as Shiraz, Cabernet, Grenache, Chardonnay and Riesling growing particularly well. “We are starting to see some new alternate varieties come in so that's a bit exciting as well,” Katelyn said. “Quality is the main thing that everyone's driving for, and they are also trying to be as efficient as possible.”
