East: Oilseed rape desiccation and aphids

Desiccation of oilseed rape crops is well underway with only the later-maturing varieties and fields remaining.  Most have been treated with glyphosate plus pod sealant. Harvest should be relatively straightforward, as most crops are shorter than normal, providing they desiccate evenly.

The June rain has helped fill seeds and pods, although there are noticeable areas of pod abortion, especially in lower lying areas of fields and poorer soils. Hopefully, pod fill will have compensated for some of this early pod loss.

So far its been a bonanza summer for aphids. They have moved into every crop I have looked at. Despite being easily found in wheat in most cases they haven’t reached threshold for treatment.

Most spring crops have needed spraying with pirimicarb and peas and beans are still being treated where infestation is occurring. Ladybird adults and larvae are helping to mop up large numbers of aphids and in some crops are keeping a lid on populations.

Looking around winter cereals in the last few weeks it is heartening to see very good control of grassweeds. Last autumn provided ideal conditions for early season grassweed control. Moisture to encourage blackgrass germination pre-drilling allowed a glyphosate tidy-up. In many cases, delayed drilling was enforced by the rain towards the end of September. Then good conditions prevailed for pre-emergence residuals.

There were also noticeable benefits from stacking active ingredients at this timing. In many cases few blackgrass plants survived and were then mopped up with Atlantis or Pacifica (iodosulfuron + mesosulfuron). Where there are any surviving patches of blackgrass these really need to be tested for resistance and if Atlantis-resistant the mechanism of resistance needs to be established.

Trials this year on Atlantis-resistant populations have achieved 95% blackgrass control with residual stacking and sequencing. This sort of approach might be needed this autumn if crops are going to be drilled earlier as delaying drilling from mid-September to early October can have a massive impact on blackgrass numbers.

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