Oilseed Rape Establishment Updated for 2020
Key points to aid establishment of your oilseed rape crops this year
1. Leave a long stubble and conserve moisture – Adult CSFB can distinguish green oilseed rape cotyledons emerging against a brown seedbed. Avoiding a “brown” seedbed and leaving stubble/residue present can confuse the adult flea beetle as they migrate into crops around mid-August. – Retaining stubble/residue will also help to conserve soil moisture and consider double-rolling, flat rolling or using a press.
2. Drill when conditions are right – Forget calendar date and instead only drill when there is enough moisture present in the seedbed and more forecast. This can be anytime between late July/early August to mid-September. Use a vigorous variety and appropriate seed rates. – Early drilling (Late Jul/early Aug) may improve your chances against CSFB but can create additional problems e.g. Cabbage Root Fly, increased risk of Verticillium Wilt and Club Root.
3. Early nutrition – The use of DAP, sewage cake, digestate in the seedbed will help promote growth, thus increasing plant tolerance to adult cabbage stem flea beetle damage. – There is anecdotal evidence that the ‘smell’ of organic manures can help deter migrating adult CSFB from feeding on emerging OSR crops.
4. Leave existing OSR volunteers as a trap crop – Leaving the harvested oilseed rape volunteers can provide a “trap crop” for migrating adult CSFB. ADAS trials have shown a 74% reduction in adult feeding damage in newly emerging crops when volunteers were left until mid-September.
5. Home-saved seed checklist – remember the following: – Only select seed from a weed-free area of crop that has not been desiccated with glyphosate. – Seed should be tested for Germination and Erucic Acid before committing to home-saving. DO NOT home-save seed which tests above 2% for Erucic Acid. Consider also testing seed for Verticillium Wilt if this has historically been an issue on your farm. – Only conventional varieties can be home-saved, and seed must not be home-saved for more than 1 generation. BSPB royalties apply to most conventional varieties.
6. Companion crops & volunteers – There is anecdotal evidence that companion crops such as buckwheat, berseem clover and spring beans can reduce CSFB activity. White mustard is another option but should only be used in combination with the Clearfield system. – Consider leaving barley/wheat volunteers slightly longer than you may normally to act as a companion crop – but beware they can become competitive very quickly.
7. Defoliate over winter – If larvae numbers in the stem are high consider defoliating (topping or grazing) the oilseed rape crop over winter to a height of 1-2”. Ensure the crop has a sufficient tap root and avoid defoliating after the crop has entered stem extension in the spring.