June
What’s happening in oilseed rape in June
At the end of May oilseed rape crops are in varying stages of flowering, with most coming to the end of their flowering period, depending on location.
The focus for June will be the build up to seed maturity and judging when to apply glyphosate to desiccate the crop.
Spraying at the right time is vital for effective pre-harvest desiccation. Spraying too early will result in loss of yield but spraying too late increases the risk of pod shatter.
Dekalb varieties, and some other hybrids, have in-build pod shatter resistance which prevents some seed shedding in wind and hail and offers a degree of flexibility in the timing of desiccation sprays.
To judge seed maturity, get into the crop and walk fields to take samples. Don’t just sample from the edges of the field, since there is considerable variability within fields and between fields, especially where earlier pigeon attack hindered canopy development. Ideally, sample 20 pods from areas of the crop that hold the majority of the yield.
During sampling, look for seed colour change. When the majority of seeds have changed from green to brown, seed maturity is around 30% and ready for spraying.
When spraying, pay attention to spray quality for optimum coverage and canopy penetration. Using water volumes of 200 – 250 L/ha will help in thicker crops. Then benefit of low-drift formulations of glyphosate, such as products in the Roundup range will also aid coverage of the crop.
Spraying earlier in the day when the relative humidity is higher will help the spray to better penetrate the crop. Where spray timing isn’t optimal, Roundup is formulated to work better than generic glyphosate formulations in hot and dry weather, and is also rainfast in one hour.
A pre-harvest glyphosate application will also remove any remaining weed populations, particularly difficult to control grass-weeds, before harvest.
After spraying, it’s important to be patient and wait for pods and stems to be fully fit for combining., Usually this is a minimum of two to three weeks, depending on the weather.
Priorities now:
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Walk fields to monitor seed maturity
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Apply glyphosate as a desiccant before harvest