A new, longer-acting pre-emergent grass and broadleaf weed herbicide for use in vine and tree crops already has demonstrated its strong effectiveness for growers in trials, including for control of weeds along property fence lines.

Alion is a new Group 29 (formerly Group O) broad-spectrum herbicide containing the active ingredient, indaziflam.

Developed by Bayer, it provides pre-emergence weed control for up to 10months, offering potential to save on applications and, importantly, allowing growers to focus on other management activities. 

Tim Murphy, market development agronomist with Bayer in SA, said in addition to vineyards, Alion could be used in almond and citrus orchards for pre-emergent grass and broadleaf weed control.

“Traditionally, grape growers will base their herbicide program around a knockdown product, and some will also include a pre-emergent herbicide,” Tim says.

“Alion now provides those growers with an alternative Group 29 mode of action herbicide to use under vines, as well as a very flexible window of application. 

“It can be applied from dormancy through until after budburst. The timing of application is only limited by the knockdown herbicide you choose to mix with it.”

Much like in vines, Alion delivers an alternative mode of action herbicide for almond and citrus growers to use, with the same flexible application window benefit.

“The long-term residual control is especially useful to citrus and almond growers, particularly for keeping the ground clear of weeds for harvesting in almonds and ensuring the weeds that harbour pests that are detrimental to export of citrus are not present, “Tim says.

“Another feature of Alion is its flexible, low dose rate range. Alion can be applied from 50 mL per hectare all the way up to 150mL/ha.

“In the first year of application, Bayer recommends Alion be applied at 150mL/ha to get weeds under control and reduce weed seed banks, and then the rate can be adjusted in following seasons.

“Growers could go to one application of 100 mL/ha in the second year, or they could go with two low-dose applications, at say 50-75mL/ha, split over a six-month period.

“As long as growers don’t exceed150mL/ha sprayed area over a12-month period, they really can select the rate required to gain the length of weed control desired,” he says.

Tim says the trials around the country, featuring long-term, repeat applications of Alion in crops, have also demonstrated exceptional crop safety across the application window.

Fence line trials on properties are highlighting the benefit of the alternative mode of action herbicide as well for safe, long-term control of grass and broadleaf weed populations, which also provides a breakthrough in herbicide resistance management.

Tim says the trials around the country, featuring long-term, repeat applications of Alion in crops, have also demonstrated exceptional crop safety across the application window.

Fence line trials on properties are highlighting the benefit of the alternative mode of action herbicide as well for safe, long-term control of grass and broadleaf weed populations, which also provides a breakthrough in herbicide resistance management.

He says on many properties, fence lines provided a good bridge for weed seeds to spread, as well as a green bridge for harbouring pests and diseases, and Alion allowed alternative mode of action chemistry to be used along fence lines compared to that commonly used in paddocks.

“It can help break the bridge and limit resistance development.”

Along fence lines, he says Alion is ideally used prior to weed germinations, where it remained on soil surfaces for up to four weeks before rainfall incorporation. If weeds are present, it always should be applied with a knockdown herbicide.

“It’s very compatible with pretty well all knockdown products currently used in the industry and it has a sufficient margin of safety when applied near trees, as reflected in the ability for it to be used in high value orchard and vine crops, allowing it to be applied along all fence lines,” Tim says.

An exceptionally long-term fence line trial at Birdwood in the Adelaide Hills, on an existing weed population, has compared Alion applied at 150mL/ha with Roundup UltraMAX at 2.5L/ha alongside an industry standard, Terrain Flow, applied at 730mL/ha with the same rate of Roundup UltraMAX.

“A unique aspect of the trial is we had some perennial and annual grasses, so it has given us a good view of what Alion will do against all species along the fence line.”

“Another interesting point is that the Alion sat on the surface for about three weeks before around 12 mm of rainfall was received to incorporate it.

“What we saw after the rainfall was initial flushes of grass and broadleaf weeds and they were quickly controlled as they emerged. We saw that through the whole growing cycle as weeds germinated following rainfall events.

“We are now well into the second year of the trial and we’re starting to see some weeds emerge in all treatments, but the Alion plots are still relatively clean, which is showing depletion of the weed seed bank and the long-term residual control it provides.

“In the terrain flow industry standard treatments, weeds started to come through after the nine-month period, with the perennial grasses dropping seeds for the season to come, whereas the Alion plots had very few weeds coming through.”

Tim says the Birdwood site featured a heavier soil type, which, also with good rainfall through the Adelaide Hills, added to the strong length of control from Alion. Other trials on lighter soils have shown slightly shorter weed control of around nine months plus.

Heading into winter, Tim says he expected weeds would emerge in all treatments, but there could be less in the Alion plots “because it has depleted the seed bank beautifully”.

He says an effective, long-term fence line weed control strategy with Alion could include two years of applications at 150mL/ha, before rotating to perhaps knockdown product or introducing alterative mode of action treatments and other long-term industry standard pre-emergent herbicides in the third year.

Further trials with Alion are being conducted by Bayer and vine and tree crop growers have the opportunity to view its effectiveness first-hand and understand how it could be used in their weed management programs.

For further information on Alion and the trials, growers can contact their local Bayer representative or sales agent.