Tillage: Beneficial organisms can only do so much for pest control
Published 11/11/2015 | 02:30
The unseasonably warm weather over the last month has allowed for a lot of winter cereals to be sown in excellent conditions and for those crops to emerge well.
Strong vibrant rows bursting from the soil are the order of the day and are a joy to look at in most cases.
However, in some respects, it's easy to get carried away with such excellent conditions.
Warm autumn weather can cause problems too. The priority action is aphid control. High temperatures have allowed for a huge influx of aphids to proliferate, and where seed treatment was not chosen, control is a priority on emerged crops. However, I have noticed very high levels of beneficial organisms such as ladybirds and spiders, no doubt as a result of the high temperatures and abundant food supply.
Ladybirds have been absent for most of the season and a late season flush is notable, but their presence at such high levels does provoke a conundrum.
Even putting aside the environmental implications, in the right circumstances beneficial organisms are a far more effective control mechanism for aphids than any insecticide.
For one thing they don't turn their nose up at knock-down resistant (KDR) aphids when they are selecting their next meal. KDR aphids are resistant to synthetic pyrethroids, the mode of action for all insecticides (except for one, the most non-selective of them all) that have label recommendations for autumn application on cereals.
The question that has to be asked is should aphid control be left to nature?