Grass weed control before and during harvest
Author: Jimmy Staples
Unfortunately, there is no room for a holiday when it comes to controlling grass weeds as one slip-up can lead to large quantities of seed being introduced back into the seed bank and undoing a lot of the good work that has already been done during the growing season. There are a number of actions that can be taken now and during the harvest that can complement actions already taken and enhance the level of control achieved.
With the plant protection season drawing to a close, now is a great time to get back into crops and identify any potential issues. At this time of the year, grass weeds will have emerged above the crop canopy and when they have headed out, it is the easiest time to identify them. The main grass weeds that we need to be concerned about are as follows:
Grass Weed Control: Before Harvest
All of these grass weeds can multiply rapidly so a zero-tolerance approach should be taken especially where herbicide resistance has been identified. At this stage in the year, preventing seed return should be a priority. Walking your crops after the final sprays have been applied is a good habit to get into as it allows you to identify any troublesome patches within fields that may not have been controlled by herbicides.
It’s worthwhile taking samples from these weeds and sending them off to the Teagasc Enable Conservation Tillage Programme for resistance testing. We have confirmed resistance in populations of wild oats and ryegrass here in Wexford so it pays to be vigilant.
Where crops are clean and herbicides have done their job, pay attention to areas where the sprayer may have missed such as the ins and outs on headlands, field gaps/gates and areas on the headland where turning. These areas can provide useful information about what weeds are in the field and allow you to plan ahead if something new or unusual is found.
Practical options for preventing seed return will focus on rogueing which is your most cost-effective tool where populations are low. Where larger patches are identified, crop destruction or whole cropping may have to be considered depending on the current crop and your planned rotation.
Grass Weed Control: During Harvest
Avoid harvesting areas where a significant population of grass weeds is present as you risk spreading weed seeds further across the field and potentially through your farm or where harvesting and baling are done on hire to another farm.
During harvest, machine hygiene has become increasingly important to help stop the spread of grass weeds and particularly where resistant weeds have been identified. Combines and balers are two of the biggest culprits when it comes to the spread of grass weeds, therefore it is important to clean down these machines when moving from field to field or farm to farm where grass weed issues have been identified.
Where possible, combines and balers should be blown down before moving to a new field or farm. Many newer combines will have a cleaning programme which can simplify the task and reduce the time involved. Having a compressor or a leaf blower at hand will greatly speed up the job. Nobody can be expected to fully clean down a combine or baler in the field but spending half an hour cleaning down a machine could prevent years of heartache and frustration.
Putting a strategy in place to help control and stop the spread of grass weeds can be relatively straightforward, it’s just a matter of finding the time to sit down and make a plan.
If any customers have an issue with grass weed, please contact Jimmy Staples directly.
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