The challenge of controlling vine suckers in the current labour markets is being addressed with a herbicide option on many vineyards across the Barossa region of South Australia.
Agronomist Shaun Falkenberg, Farmer Johns in Nuriootpa, SA, says unwanted shoots are 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,” he says.
“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 says another problem with suckers at the bottom of the vine is 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.”
Shaun says one option for growers was to remove the suckers manually.
“Physically removing them is extremely expensive, with the current labour market, with most people paying between $30 and $40 an hour for labour,” he says.
“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. “
So, we found a very effective way to remove them was with a product called Spotlight Plus Herbicide.
It is registered for sucker removal, and we target them before they are 250mm to 300mmin length and as long as we get good coverage, it burns them of 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.”
Shaun 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 of immediately,” he explains.
“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 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 Herbicide 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.”
As an agronomist in the Barossa Valley, Shaun 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 past 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.”
