Coles Contracting delivers vineyard management, contracting and grape harvest services throughout Marlborough, New Zealand’s largest winegrowing region. Their Viticultural Operations Manager Richard Barnes has worked in the wine industry across New Zealand and Australia following his graduation from Lincoln University.
Richard says the attraction of viticulture is its combination of art and science. “We work with people with vineyards from three to 100 hectares in size – it’s a very dynamic business. I really enjoy being a part of the wine industry.”
Richard says he’s had to manage blocks with glyphosate-resistant ryegrass, but it wasn’t an issue that was new to him, having already encountered it in Australia.
“Over time, ryegrass competes with vines for moisture and nutrients, affecting their vigour. Viticulturists also have the task of preventing resistant ryegrass spreading to neighbouring blocks or adjacent properties.”
Before using the residual herbicide Katana, Richard had tried other herbicides with varied success, often adding extra herbicide passes.
“It was an easy process to apply on the SWNZ website to use Katana on a block that had glyphosate-resistant ryegrass. The herbicide was then applied pre bud-burst and we found its five month residual effect cut out an extra herbicide pass. It was successful and the client was happy with the result.”
Containing 250 g/kg flazasulfuron in the form of a water dispersible granule, Katana provides long-term residual control of problem weeds.
Alex Easton, UPL NZ Ltd Regional Manager Upper South Island, says the results being obtained with Katana are exciting.
“We believe Katana is going to be important for growers in terms of savings on fuel and staff time as it can provide control for up to five months. Its long-lasting efficacy means vineyards can focus labour and resources on other jobs. It also has a long and flexible application window, and we’ve seen it work well in some tough conditions.”
Katana should ideally be applied in winter, between harvest and bud-break, when soil is bare and there is no green cover. Please note, Katana can’t be used on the same block two years in a row.
Fruitfed Supplies Senior Technical Horticultural Representative Blair McLean recommends careful preparation before spraying Katana, using a systemic herbicide for optimal results.
“We’ve followed several years of trial work with Katana. One grower used Katana as soon as it was registered, and the results we saw on resistant ryegrass and other weeds were outstanding.
“It can save one or two passes of alternative herbicides. The following year, growers have also found the weed pressure was decreased.”
Rapidly absorbed by roots and shoots, Katana inhibits acetolactate synthase (ALS), a key enzyme of base amino acid production. As a result, downstream synthesis of vital plant proteins is stopped, and the plant dies. When used on germinating seedlings, Katana acts in the soil to prevent further plant growth and emergence.
Soil needs to be free of significant plant material before using Katana. If weeds are present, Katana can be mixed with a knockdown herbicide. However, if there is significant weed cover, apply a knockdown herbicide first, then use Katana once weeds have collapsed.
More than 15 trials were conducted in Marlborough, Hawke’s Bay and Gisborne throughout 2016-2021. In addition, pot trials were carried out at Massey University to confirm Katana’s efficacy on glyphosate-resistant ryegrass. Glyphosate remains one of the most widely used herbicides in New Zealand and can be mixed with Katana. Prior to use, SWNZ members must apply for written permission before using Katana as it is registered for glyphosate-resistant ryegrass. This is a simple process on the NZ Wine website.
For more information on successful weed control in your vineyards with Katana, talk to your Fruitfed Supplies Technical Horticultural Representative.
