South: Oilseed rape hit by feathered pests

One of the reasons I like winter barley in an arable rotation is that it allows us to get winter oilseed rape drilled in a timely fashion, from mid August onwards. It also allows us to have a five-year gap between rape crops, which helps to negate some of the detrimental effects of earlier drilling. A fairly commonly expressed observation this year was that the longer the gap between rape crops the better – or least badly – it yielded.

So this year, quite a chunk of OSR was drilled around 20 August. Only to get 75mm rain dumped on it over the August bank holiday. The crop didn’t like it one bit, and, having panicked the growers into camping out to watch for flea beetle, some crops started to disappear. Ironically not from flea beetle, and to a large extent not even slugs, but from pigeons and partridges taking advantage of a slow-emerging rape crop, giving them a tasty, tender morsel of a rape plant at cotyledon stage.

Fortunately, on the whole, the re-drilled crops have come away and have recovered well. We still haven’t experienced the flea beetle problems that have plagued the eastern counties, but the blackgrass emergence has been astonishing. Carpets of blackgrass (even after glyphosate before re-drilling) at two leaves with a rape crop at cotyledon stage – I think we’ll be putting a lot of hope on our propyzamide and carbetamide applications this year.

Having had a wet, cold August we’ve gone into a hot, dry September. Winter cereal drilling is well on its way, with some finished already. A technical meeting with the major residual herbicide manufacturers revealed that even in dry conditions it’s worth pushing ahead with pre-emergence strategies. Just be aware that in conditions like these, seed-bed quality and coverage (ie spray quality) are even more important. Basically, no air-induction or low-drift nozzles.

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