The recent warm spell has triggered cereal aphids flights with several species flying into crops in the last couple of weeks. The return to cooler wet weather will slow them down, but aphids can now be found building up numbers on crops.
Look for aphids on leaves on warm sunny days, and consider an aphicide if aphid colonies can be found on 50% of plants. If you are seeing ladybirds or hoverflies in crops then hold off on any aphicides, as these specialist aphid predators will do a good job of mopping up aphids. Check crops again a few days later and if aphids are still on 50% of plants then consider the aphicide option.
Note that there is evidence of resistance in the grain aphid to the pyrethroid insecticides in Scotland, so use these insecticides with caution and only treat crops if thresholds have been exceeded.
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