South: Aphids numbers surge in crops

Insects are the big watch out for us here at the moment. Aphid numbers on cereals and oilseed rape are the highest for many years and we’re finding the first gout fly eggs on wheat. Leaf miner is making its presence felt in many oilseed rape crops. There’s more than enough cabbage stem flea beetle damage too, while little black turnip sawfly caterpillars we first encountered four years ago are proliferating.


This is hardly surprising given one of the warmest Septembers in the past 100 years, let alone the early October heat wave. With the exception of aphids, these insects rarely present a major threat on their own. But the combinations we’re seeing this season can be very damaging.


We’re gearing-up to nip problems in the bud wherever necessary with a timely insecticide spray, especially in oilseed rape which is all too easy to ignore between early weed control and traditional phoma spray timing given competing autumn demands.

The dry conditions have meant little or no phoma development to date. But insect threats could well necessitate an earlier initial rape spray than usual. In which case, we’ll need to review our second phoma timing – particularly if it stays mild – so we don’t leave too great a gap. Thankfully, the modern hybrids with top stem canker resistance scores we’re increasingly growing should give us the maximum flexibility in this respect.


Our earlier sown wheats on lighter soils took advantage of excellent seed-bed conditions to come through the ground rapidly – in just six days in some cases. However, later-sown crops have been far more variable – increasingly hot and dry conditions have made some seed rate decisions look a little on the low side, putting a premium on early action to minimise pest damage.


Ironically, perhaps, the dry conditions are also concentrating the mind as far as slug control is concerned. As heavier ground has dried out cereal seed-beds have become more open and less well consolidated. As a result, we’ve seen more seed hollowing than for many years, even with Deter-treated crops. Heavier areas of ground have already needed two pellet applications.


With autumn drilling drawing to a close, we’ll start setting up spring barley ground in the next few weeks. By getting groundwork done early the crop will go into as much moisture as possible once conditions allow from late February.

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