Warm weather increases aphids on cereal ears

Summer aphids may be a threat to harvest this year, with grain aphid numbers increasing with the recent warm weather. Growers are being advised to use a pyrethroid insecticide, such as esfenvalerate, Sumi-Alpha, to reduce direct feeding damage and loss of grain value.

"Aphids are now being found widely in wheat crops. The current warm weather is conducive to their build up and current levels could quickly increase. Not only can grain aphids cause a yield penalty by direct feeding, but their exudates can encourage the development of saprophytic fungi, leading to grain discoloration and loss of grain value. More significantly this year there appears to be low levels of natural predators, so any increase in the aphid population may not be sufficiently checked," says Dr. David Stormonth, Technical Manager for Interfarm UK Ltd.

"Control is relatively easy and inexpensive, with the use of an effective pyrethroid insecticide with a quick knockdown, such as esfenvalerate. Sumi-Alpha is a highly active and fast-acting pyrethroid, giving good knockdown and with long lasting persistence, making it very suitable for this purpose. Other pyrethroids may give knockdown, but aphid colonies can re-establish," warns David.

Containing 25 gms ai/litre esfenvalerate, Sumi-Alpha is recommended on all varieties of wheat and barley for the control of aphids at a dose rate of 200 ml/ha. "This is a higher dose rate than the autumn BYDV rate because of the larger crop canopy. Lower rates may give knockdown, but with reduced persistence. Use water volumes of at least 200 litres/ha for coverage. Sumi-Alpha can be used up to Growth Stage 77 (grain milky ripe) in wheat and up to Growth Stage 73 (early milky ripe) in barley," says David.

For further comment and information, please contact Dr. David Stormonth, Technical Manager, Interfarm UK Ltd. on 01354 741414 or 07818 036506 (mobile) or via e-mail david.stormonth@interfarm.co.uk