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Haloxyfop in canola

30/4/2024

In recent years, residue testing by the National Residue Survey has detected haloxyfop residues above the Australian Maximum Residue Limit (MRL) of 0.1 mg/kg in canola traded domestically. Verdict™ 520, Firepower®, Exert™ 520, Asset™ and Inquest® are examples of common trade names for haloxyfop.

In response to these detections, CBH has been testing for haloxyfop in canola for the past five seasons. CBH tests for chemical residues during and after harvest to help maintain Western Australia’s reputation for supplying clean and safe grain. This testing has revealed a significant decrease in haloxyfop use by Western Australian growers. 

The European Union (EU) recently announced that the haloxyfop MRL in canola will be reduced to 0.05 mg/kg, or half of the Australian MRL. 

To maintain our strong trading reputation and ensure continued market access, it is critical that exported canola meets import country MRLs. Current CBH stocks are well below this new MRL allowing Western Australian growers continued access to this valuable market.

Technical details

The label use of haloxyfop in canola can result in residues in grain exceeding the Australian MRL.

For example, below is an excerpt of the “Directions For Use” from the Verdict® label:

"Apply from 2nd leaf to 6 leaf stage of crop growth and before bud development."

"DO NOT apply after the commencement of stem elongation."

"This means that application must not occur after the 6th leaf stage, or if stem elongation commences before the 6th leaf stage, application must not occur after stem elongation has commenced."

 

Please visit the APVMA website for all Haloxyfop chemical labels available in Australia. 

 
This only allows a very narrow window for application if observing the 2-6 leaf stage guide, which can be reduced further if plants begin stem elongation before the 6-leaf stage, which frequently occurs. Delays due to breakdowns, weather events and logistical complications, combined with earlier planting times, can easily result in the crop growing past the label application stage for haloxyfop. Staggered germinations from dry starts can also increase the complexity of herbicide timing.

Haloxyfop was first registered in canola in 1998 when the most common varieties grown in Western Australia were Karoo, Narendra and Oscar. Since 1998, canola varieties that are grown have changed dramatically with the introduction of shorter season varieties and hybrids. These newer, advanced varieties may transition into stem elongation earlier than the traditional varieties, used for testing when haloxyfop was first registered. The varieties grown today also yield a lot higher and can have increased efficiencies in use of water and nutrients, which could result in higher levels of haloxyfop accumulated in the grain.

CBH encourages you to discuss alternatives to haloxyfop with your agronomist. There are other products that can be used to control grass weeds in canola that do not cause a residue issue. If targeting erodium, there are some canola systems with alternative methods of control. Manipulating pastures in the rotation is also a helpful way to reduce erodium numbers; haloxyfop and many other products can be applied to legume pastures.

For more information:
Growers reminded to avoid haloxyfop use after EU confirms decision - Grains Australia 

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