Winter cereal growers urged to remain vigilant against aphid pests after mild autumn

Aphids are soft-bodied insects with piercing-sucking mouthparts
Aphids are soft-bodied insects with piercing-sucking mouthparts

Winter cereal growers are being urged to remain vigilant against aphid vectors of barley yellow dwarf virus (BYDV) after the mild start to autumn, warn crop specialists

Farmers are urged to remain vigilant, especially when growing crops with a high yield potential, such as hybrid barley.

Aphids are soft-bodied insects with piercing-sucking mouthparts. They feed in the phloem which circulates carbohydrates throughout a plant. Aphids often excrete a sugary waste called ‘honeydew’, and usually feed in colonies on new, succulent shoot tips or young leaves. Heavy infestations delay plant development and impair plant health—causing leaf curling, stunting, or wilting.

According to Syngenta field technical specialist, Max Newbert, yield losses from BYDV can be as high as 70-80% in winter barley and as high as 25-30% in winter wheat.

Barley yellow dwarf disease is transmitted by aphids
Barley yellow dwarf disease is transmitted by aphids

BYDV was particularly bad last season after a similarly mild autumn plus a mild winter allowed prolonged aphid activity, he says, so growers have to be vigilant against a similar thing happening again.

“Last season, there were a lot of issues with BYDV because people only relied on a seed treatment without using a follow-up aphicide spray,” says Mr Newbert.

“Most growers will have used a seed treatment against BYDV again this season. But if they drilled early, that seed treatment could be running out of steam. Also, there are similarly high numbers of bird cherry aphids about – one of the main vectors of BYDV – as there were last year.

“Farmers need to be sure to check crops regularly for the first sign of aphid activity, indicating when seed treatment protection may be running out.

“The thing to remember about BYDV is that spraying against it is a relatively low input cost, but with these sort of yield losses at stake effective prevention can give a massive benefit – especially if you’re growing a high yielding crop, such as hybrid barley."

The initial symptoms of BYDV infection are normally seen as individual plants scattered through the crop with bright yellow upper leaves. Later, as infection spreads, larger areas of the crop become infected appearing as patches of bright yellow and severely stunted plants. BYDV is most damaging to plants infected in the early growth stages. The effects of BYDV may be exacerbated by other stress factors, including adverse weather conditions, soil acidity and other pests and diseases.