Canary grass is a growing problem on Irish tillage farms. Its small seeds allow the grass weed to spread easily. It is extremely competitive and while there is little information on it, its appearance in the field suggests a significant effect on yield, aside from difficulty at harvesting.
Lesser canary grass is turning into a serious problem in some areas, particularly where spring barley is common and continuous.
At present there is no known evidence of resistance to herbicides in lesser canary grass.
The strong-stemmed grass is extremely difficult to control without a herbicide
However, current control options are limited, usually not on the label and can add significant cost to a crop’s herbicide programme. That said, it should be noted this is a necessary cost if canary grass enters your fields.
The strong-stemmed grass is extremely difficult to control without a herbicide as it tends to scatter itself across fields, showing a dotting of individual plants across crops, as well as appearing in thick bunches, outcompeting the main crop.
At present, herbicide options for control are limited. Axial Pro and Foxtrot both offer control, although it is not listed on their labels (Foxtrot has awned canary grass on its label). A rate of 0.82 litres/ha of Axial Pro is needed for control of canary grass, while a rate of 1.0 l/ha of Foxtrot is needed.
Early use of these herbicides is best, but Axial Pro can be applied up to GS41 – the flag leaf sheath extending stage on winter and spring wheat and barley. Foxtrot can be applied up to GS31 (first node detectable) on winter and spring barley and GS39 (flag leaf ligule visible) on winter and spring wheat.
Keep the weed at bay
With more and more resistance developing in grass weeds, it is essential to keep competitive weeds like canary grass at bay. Canary grass germinates in May, so if a small number of plants are found on the farm, when it is too late to spray, it is essential to rogue the weed or even spray off that particular patch with glyphosate or cut the area before the plant goes to seed.
If you know you have a problem, as there was canary grass in a field in the previous season, then spraying is advised to suppress the weed.
As mentioned earlier, and like many grass weeds, canary grass is easily spread from one field to another.
If you are harvesting in a field with canary grass, do not travel to the next field without cleaning down the combine.
Spraying is costly and is also the last line of defence
For this reason it can also make sense to spray headlands where the combine first travelled as it may have carried and spread seeds to them.
Canary grass mainly begins to germinate in May, but can germinate again later in the season once a crop has been harvested. These late-germinating plants should not be allowed to go to seed. Cultivate the area or spray with glyphosate to prevent this.
Spraying is costly and is also the last line of defence. Like many grass weeds, canary grass makes its way into the field from the headlands. Where the plant was been seen in the headlands and action was taken to control it then, it may be worth spraying the headlines again the following year to avoid spread into the field.