New technologies to help kick Caltrop to the curb

30 January 2020

Preventing Caltrop from becoming a thorn in the side of viticulturists this summer was the focus of a recent weed control workshop held in Auburn.

Attended by more than 30 Clare Valley Wine and Grape Association (CVWGA) members, the event demonstrated new and emerging technologies for controlling weeds. Several members of the CVWGA worked closely with Primary Industries and Regions SA (PIRSA) pest and weed coordinators to plan the event.

Kirribilly Viticulture Site Supervisor Allen ‘Spog’ Weedon said the workshop identified several alternatives to spraying herbicides that could be part of an integrated pest management approach.

“It was great to learn some new options for weed control, instead of just relying on spraying year after year, which is becoming more difficult as the number of vineyard-registered herbicides decline,” he said.

“Caltrop and Silverleaf nightshade are the biggest weed issues for us and while Silverleaf nightshade has been relatively easy to keep at bay with spraying, Caltrop spreads rapidly because its spiny burrs stick to tractor and car tyres, along with footwear, and are carried to other areas.”

Mr Weedon was impressed with the workshop’s demonstration of the Aussie Prickle Picker, a tow-behind roller that collects the Caltrop burrs as it moves along vineyard rows. “I think the Aussie Prickle Picker will be really effective in reducing the Caltrop seed bank and it also helps us to cut down our chemical use,” he said.

Natural Resources Northern and Yorke Landscapes Officer Cameron Watson said recent rain events in the region combined with hot days were ideal conditions for weeds like Caltrop (Tribulus terrestris) to emerge. “Caltrop is a summer-growing weed that germinates after summer rain and grows very quickly. It thrives on bare ground, so spraying with glyphosate and removing surrounding vegetation can help rather than hinder it,” he said.

“Each plant can produce more than 1000 seeds which can remain viable for many years, so it’s important for grape growers and other landholders to act quickly to keep on top of it.”

Mr Watson, together with Troy Bowman and Jennifer Gillis from PIRSA provided information about best practice weed control for participants at the breakfast event, which showcased a range of weed technologies including organic herbicides, steam weeding, the Aussie Prickle Picker and the Rotowiper, which applies herbicide via a carpeted, rolling drum.

Held at Schobers Vineyard earlier this month (10 January), the event was delivered in partnership with CVWGA and PIRSA Biosecurity, Invasive Species Unit and funded by Agricultural Competitiveness White Paper and Northern and Yorke NRM Board’s Bite-Size Grants program.

For information or assistance in managing weeds, please contact Natural Resources Centre in Clare on 8841 3444. Further information is also available from PIRSA’s Established Weed Facilitator, Troy Bowman via email Troy.Bowman@sa.gov.au