South: Aphid activity remains high in Kent’s crops

With all winter crops drilled and generally good pre- or peri-emergence herbicide results, the weather is dictating further applications to crops. Field brassicas are in good order, though when we next get a dry leaf a final, robust fungicide should see them through winter. Aphid activity is still high locally, so an insecticide will be included in the mix.

There are significant numbers of bird cherry-oat aphids on Deter (clothianidin) treated September drilled winter wheat, so any pass through for weed control will include an aphicide. I am still seeing “feathering” of wheat from slug grazing, so keep monitoring and pellet where needed – ferric phosphate being the best bet in wet conditions.

Soil temperatures remain high for propyzamide (Kerb) applications on oilseed rape (around 11C here in East Kent), though where Astrokerb (propyzamide + aminopyralid) is used, it could be argued that aminopyralid activity will benefit from the warmer conditions. At this time of year, with a fungicide to be applied as well, it is probably best to take whatever opportunity the weather allows. Although visible symptoms of light leaf spot are hard to find, the forecast risk is high – ensure your fungicide has activity against this as well as phoma.

I’ve spent a lot of time soil sampling over recent weeks, and suggest that adding an organic matter measurement to the usual analysis of pH, P, K and Mg is a worthwhile expense (less than £10 per sample). With less mixed farming and tighter rotations many arable soils have had their organic matter (OM) levels depleted over recent years and it’s worth considering how to raise the levels if your test results indicate they are low. Higher OM improves the resilience of soil and crops to extremes of wet and dry and improves retention of nutrients and moisture. Dung, compost, chopped straw, green manures and cover crops can all go some way to improving the soil and reducing the impact of extremes of wet and dry during key phases of crop establishment and growth.

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