MANAGING WILD OATS WITH RESISTANCE TO GROUPS A, B & Z.

 

Background

Peter suspected he had problems with the Group A chemistry about 10-12 years ago. It is possible that the resistant weeds actually turned up in seed that was brought onto farm. He incorporated the use of Clearfield technology into his cropping program which allowed him to control the wild oats.

 

In 2007 samples of wild oats were tested with the following herbicide resistance results :- 20% to Wildcat^® , 10% to Topik^®, 30% to Atlantis^® and 15% to Mataven^®. So we now have problems with Groups A, B and Z.

 

Discussion

The extensive use of the Clearfield crops and herbicides, whilst solving the immediate issues at the time, has probably led to some other issues over time.

 

The usual rotation has been Wheat / Barley / Canola for many years. Last year we included fababeans and chickpeas into the system. Moving forward we will include all these crops, as well as look at TT Canola and if necessary, Sorghum.

 

Whilst the inclusion of sorghum is probably an obvious move, Peter has a desire to grow winter crops for numerous reasons, the most important being to maintain trash levels to minimize the erosion risk.

 

The numbers of wild oats on the farm is generally low and of little economic consequence to the crops that are grown. The plan is to drive numbers even lower by using different chemistry groups where possible such as Group C (simazine, atrazine) and products within Group A that are still providing control (such as Axial^®, Verdict^®, Select^®).

 

Crop competition is a very valuable tool in weed control and we will have a strong focus on the establishment of uniform and competitive plant stands in the future.

 

Summary

When we got the results of the resistance test, Peter thought he was doomed. After several conversations and planning sessions, we see the issue as a manageable one.

 

To avoid or reduce herbicide resistance to Groups A, B & Z we need to consciously rotate to other chemical groups such as Group C, D & J. If the opportunity arises in the rotation where proper incorporation can be achieved, the use of Trifluralin (D) and Avadex (J) should be considered.

 

The solution to the resistance will not be in rotation of chemical groups alone, but will include an integrated approach involving crop selection, crop density, cultural practices, etc.

 

Take the time. If you fail to plan, then you plan to fail.  

 

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