Dubbo grower makes knockout blow in fight against ryegrass

Tom and his wife, Cathy, together with their son Nick and the help of nephew, Sam Coady, grow wheat, lupins, chickpeas and canola and also run cattle on their 2200-hectare ‘Enterprise’ farm, which comprises sandy and red loam soils.

The cropping program follows a wheat-canola-wheat-legume rotation and Tom said the ryegrass was becoming a growing issue across multiple crops, with resistance to Group A and B herbicides emerging in some paddocks.

“We had it really bad a couple of years ago,’’ Tom said.

The Harveys have experienced varying success with existing herbicides including Boxer Gold®, triasulfuron, as well as clodinafop with the highest label rates of the latter proving ineffective. Under certain conditions, triasulfuron also poses crop safety risks.

“We were getting a level of control, but we were relying on the legume and canola cropping phase to get good control,’’ Tom said.

On the worst paddocks, the family decided to grow herbicide tolerant canola in 2012 and this year, in the wheat phase, they have applied the new pre-emergent herbicide, Sakura® 850 WG, containing the active ingredient, pyroxasulfone.

“We are looking to use all options,’’ Tom said.

“We think we will go to windrow burning and fallow will be part of the toolbox going forward too.’’

Sakura, a highly concentrated granule from Bayer, has a low use rate of 118 g/ha.

For the Harveys, it proved to be a knockout blow in the fight this season, showing good compatibility in separate tank mixes with glyphosate as well as with glyphosate and triasulfuron for their Suntop, Livingston and Gregory wheat crops.

“We had zero summer rainfall and it was a late break (10 mm of rain on May 22), but we got a good pre-sowing germination of ryegrass,’’ Tom said.

“A week later we had 25 mm and we sowed the wheat from the 6th of June. Then we had half-an-inch (12.5 mm), then 15 mm and then 26 mm.

“Anything that germinated underneath was taken out by the triasulfuron and the Sakura got the surface germinators.

“In July we had 10 mm and then 12 mm, which fired the chemical back up, and then the rain stopped.

“It did a magic job because of the rainfall and against massive ryegrass numbers.

“The Sakura and triasulfuron was a good combo. It was a big lick at around $40 (per hectare) upfront, but it had good activity. The Sakura was magnificent and probably did 80 per cent of the job.

“With the weed spectrum we had in the problem areas, nothing else known to man would have controlled it.

“With the rain cutting off in July, if we hadn’t achieved that weed control, we wouldn’t have half the crop we have now.

“There are some strips where the boom failed and no chemical, or not a lot of chemical, went on and the difference is clear.’’

The other bonus with the Sakura herbicide this season for the Harveys was its suppression of isolated patches of wild oats, which are typical throughout the region.

“We normally spray 40-50 % of the program for black oats – and coming back later can be difficult,’’ Tom said.

“Because the country was so clean this year with the Sakura, we only had to come back in the missed strips.’’

Dean Walton, of Walton Rural at Dubbo, said the Group K herbicide definitely had a place within integrated weed management programs for the region’s growers.

“We have had an over-reliance on post-emergent herbicides and it is not working,’’ Dean said.