The challenge of controlling vine suckers in current labour markets is being addressed with a herbicide option in many vineyards across the Barossa region of South Australia.
Agronomist Shaun Falkenberg of Farmer Johns in Nuriootpa said unwanted shoots were common in vineyards throughout the area and could cause many challenges for grape growers.
“As the vines are growing, they throw suckers from old buds underneath the bark.
“We get a lot of suckers coming out from the bottom on both grafted and non-grafted vines. Suckers are a bit unsightly and it’s also hard to control weeds around them because you can’t use broad-spectrum, non-selective herbicides.”
He said the other problem with suckers at the bottom of the vine was their ability to carry disease.
“Most of the fungicides we use target the cordon area to control disease. Suckers down the bottom are quite often missed and can harbour powdery mildew, downy mildew and other diseases.
“If we get wet events, the downy mildew spores living in the ground will splash up and hit those suckers. It is important to remove them.”
Mr Falkenberg said one option for growers is to remove the suckers manually.
Physically removing sucker is extremely expensive, with the current labour market - most people are paying between $30 and $40 an hour for labour.
“Whenever we make a cut on a trunk or a cordon on a vine it creates a wound site. So, if we were to go through and physically remove them with labour-hire, we leave a wound.
“If we were to have any moisture around, we have Eutypa present in the vine, which causes cordon decline.”
We have found a very effective way to remove suckers is with a product called Spotlight Plus Herbicide, which is registered for sucker removal.
“We target suckers before they are 250 to 300mm in length and as long as we get good coverage, it burns them off beautifully and there’s a lot less labour.”
He says a grower could use a small spot sprayer on the back of a four-wheel motorbike and treat a whole block in very little time.
“It’s much less labour intensive, there’s no bending over and it's a really good product for us.”
Mr Falkenberg says Spotlight Plus Herbicide works because it is not systemic so doesn’t move through the phloem and xylem of the plant.
“It virtually hits the leaf and the shoot and burns it off immediately,” he adds.
“Spotlight Plus just desiccates and shrinks that shoot to nothing – no wounds to worry about.
“There are no infection points for the future Eutypa for the plant. Eutypa grows backwards down into the trunk, and we certainly don't want any infections that close to the ground."
He says the active ingredient in Spotlight Plus is carfentrazone but it differs from other carfentrazone as the formulation is purpose-designed for sucker control in vine and tree crops. In fact, it is the only product registered for sucker control.
“Quite often when we're using other carfentrazone products in the field as spikes with our other under-vine herbicides, we get a lot of spotting up in the canopy.
“Spotlight Plus has an oil adjuvant system built into the product and that helps when spraying suckers under the vine canopy. Where we put it, is where it stays.”
Mr Falkenberg is an agronomist in the Barossa Valley and looks after a wide range of customers and grape varieties.
“Shiraz is a flagship for us, but we also have excellent Riesling, very good cabernet, merlot, grenache and mataro in the Barossa Valley as well.
“I’ve been in the reseller side of viticulture for the last 25 years and look at the full picture before recommending a product.
“If it comes down to a product that has to be applied, it's always got to be something which is reputable, and something where we get some really good backup support.”
