Weather conditions and innovations in crop protection products have driven a shift in weed control for oilseed rape growers in Ireland.
A significant number of farmers are returning to the crop due to high prices and strong market demand.
Corteva Agriscience is urging farmers to familiarise themselves with how weed control strategies have evolved in the past three years as the window for post-emergence herbicide applications open.
Corteva says those growers may not be familiar with recent advances in weed control products which allow them to reduce their establishment risk and be more targeted in their approach to weed control.
This is expected to be especially important in 2022 as dry weather has prevented some pre-emergence applications. Where sprayers did run, a lack of moisture may have reduced the efficacy of the chemistry.
Targeting cleavers, poppy, shepherds purse and fumitory, Belkar® herbicide offers an alternative to traditional approaches which rely on pre-emergence control and, as autumn temperatures fluctuate, chemistry that will cope with the swings in day and night temperatures.
Corteva’s National Field Technical Manager for Ireland, Liz Glynn, said: “As an industry we have learnt a lot very quickly about how to establish the crop while reducing risks at the same time.
“Belkar allows for a fundamental change in farmers’ strategies for controlling weeds. It means they can tackle what is visible, and not spend on herbicides before they know how well the crop is going to emerge.”
Arylex™ active has been formulated with picloram to create Belkar and the product can be applied from 2 true leaves all the way through to side shoot development (GS21).
“As little as 0.25l/ha after emergence can effectively control the most common broadleaf weeds,” Liz said.
“Chemistry will be more effective when weeds are small and not shadowed by the crop, which can stop weeds in their tracks before they have a chance to really get going. Waiting until spring is tempting, but by that point they will be more difficult to control with the added risk of resistance.
At two true leaves, an application of Belkar at 0.25l/ha will take out the weeds which have germinated alongside the crop and, in some circumstances, that will be enough broad-leaved control before an application of Astrokerb® (propyzamide + aminopyralid) or similar later on.
In high weed pressure situations where a second germination is visible, growers have the option of a second 0.25l/ha spray two-to-four weeks after the first application.
Depending on workloads, growers can wait until six true leaves of the oilseed rape to tackle bigger weeds at a rate of 0.5l/ha of Belkar which will take care of the weeds going into the autumn.