South: Secondary oilseed rape flowering causing concern

Despite some seriously cold nights through much of May, we’ve seen remarkably even oilseed rape pod set from a good and not overly-prolonged flowering. Pod density is far from excessive and most of our crops are well-structured and standing strongly at a reasonable height with pods filling nicely.

It’s pleasantly surprising to see so much green leaf so well down our plants, confirming we’re getting the sort of light penetration throughout the canopy we really want. And there’s little, if any, light leaf spot to speak of.

The only possible fly in our oilseed rape ointment at the moment is the sudden, late flush of secondary flowering we’ve had in some varieties on our thinner ground, along tramlines and in areas of pigeon damage. The number of small, later maturing pods we’re seeing on sub-branches of secondary racemes here could give us a big desiccation timing headache as well as robbing resources from our main yield-bearing pods.

With the sort of modern hybrid canopies we’ve built this year we’re going to have to be more patient than ever with our pre-harvest glyphosate. To capture as much yield and oil as possible we must avoid going in too early, waiting instead until the pods lower in the canopy carrying most of our gross output are fully ready. The pod shatter resistance we have in much of this year’s crop will be really valuable in giving us this leeway, without going overboard on pod stickers.

An unsettled and decidedly windy May has been far from ideal for our wheat spraying, giving a long tail to our T2s. Even so, good early spray timing and the cooler weather has allowed us to keep septoria well under control. This means most of our wheats are going into flowering with three or even four very clean leaves.

We’re seeing a good bit of tipping on the flag leaves, but this almost certainly reflects some very cold nights around their emergence. So, with our emphasis on quality wheats, fusarium and microdochium are our key concerns as our thoughts turn to T3.

We’re building our programmes around prothioconazole with tebuconazole for the best balance of ear disease control. Having deliberately supported SDHIs with epoxiconazole and metconazole at T2, this is also giving us the triazole rotation we’re looking for to keep up the pressure on any late season septoria development.

The great unknown with the wheat just now is orange wheat blossom midge (OWBM). Unsurprisingly, with the weather as it has been up to the end of the first week in June, our trapping has shown little or no activity so far. Which means our earliest wheats – just coming into flower – won’t need any protection. We’ll be keeping a very close eye on the traps everywhere else, though; especially if the weather turns as warm and settled as some forecasters have been predicting.

Here’s hoping for an altogether stress-free flowering and a sunny, but none too hot run-in to harvest.

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