Expert advises how to get the best grass weed control from tri-allate this autumn 

The dummy granules can be used up to three times before they need to be replaced, and farmers can request them through the Gowan website.

Gowan’s country manager Hank King said: “These are the same granules that are used in the product, just without the active ingredient, and they closely reflect the product. Using dummy granules ensures the most accurate calibration. 

“Accurate calibration is important for product stewardship, which is complementary to efficacy. Grass weed control is a huge challenge, and we want to ensure growers get the most from the herbicides they use.” 

Runs well for the whole season 

Oxfordshire farmer and contractor Will Hazell utilises a Techneat applicator mounted to a 24m Sands self-propelled sprayer. He farms light brash and sandy soils, whereas the main customer base for his Avadex spreading service is further east on heavy clay land, which tends to have more challenges with grass weeds. 

Mr Hazell has spent some time with the Techneat experts calibrating his applicator. Combined with the GPS autosteer on the Sams sprayer, he finds the Avadex application highly accurate. 

The farmer said: “The Avadex (granule size) is so consistent out of the bag. Once you have it set right, it tends to run well for the whole season. 

From a peak of applying 2,000 ha per season of Avadex to customers’ farms, demand for spreading contractors in the areas has reduced locally, according to Mr Hazell. 

“I wouldn’t say the usage of Avadex has gone down. With the grants available, a lot of people have bought new drills, and they tend to spend a little extra to have an Avadex applicator fitted to the back.  

“I know some farmers who won’t even think about planting wheat without using Avadex,” he added.  

Despite the challenges of establishing crops last autumn, the farmer still expects most heavy land growers with grass weed concerns to drill the bulk of their crops well into October.  

Best practice when applying Avadex with a drill 

The benefit of applying Avadex with a drill-mounted applicator is that a farmer is guaranteed a robust start to their herbicide program if the weather changes and compromises following pre-emergence applications, said Gowan’s country manager. 

Additionally, it saves the cost of an additional pass to apply Avadex Excel separately. 

“Given the uncertain weather we have seen over the last few years at drilling time, it makes complete sense to take this approach where possible.” 

Mr King has further advice for the growing number of farmers applying Avadex Excel at drilling.  

He explained: “The most important requirement is that the product is applied according to the label and, being a pesticide, the drill operator must be PA4G qualified if the application is to be made in the same pass as the drilling operation. 

“The granulator applicator also needs to be calibrated in its own right and include patternation testing. The aim is uniform coverage across the drill width for best efficacy.  

When using Avadex, the expert advises operators to sow winter wheat below 40mm. The crop seeds can potentially germinate within the herbicide residual layer in the soil if it is sown shallower than this.  

It is also essential that the drill slots are adequately closed, and the seed covered before Avadex is spread at the back of the drill.  

Mr King continued: “Drills can often be run at a decent forward speed, but operators must remember that they need to drill at the speed of the slowest operation. In some cases, this means slowing down to ensure optimum Avadex coverage.  

“It is the same for weather conditions. Drilling can carry on in substantial winds without a problem, but this is not true for Avadex spreading.”  

He also said that rolling will consolidate the seedbed, which aids crop establishment, reduces slug activity, and provides better conditions for the efficacy of pre-emergent herbicides.  

However, the 40mm drilling depth needs to be maintained to ensure the safety of the crop, and whilst Mr King has seen no issues with rolling after applying Avadex Excel with the drill, the seed depth must not compromised due to the rolling action. 

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