Cereal Aphids

  • Cereal aphids usually dominate the aphid bulletin from midsummer onwards. These species can increase the risk of aphid-transmitted potato viruses, including PVY, because they often occur in high numbers in the suction traps and individual species can make a high contribution to the overall aphid vector pressure index.

  • The three main cereal aphid vector species recorded during the season are the rose-grain aphid (Metopolophium dirhodum), the grain aphid (Sitobion avenae) and the bird cherry-oat aphid (Rhopalosiphum padi).

  • Cereal aphids are also important pests of cereal crops; they cause direct damage through feeding and transmit viruses such as barley yellow dwarf virus (BYDV).

First flight predictions for season 2026

Rothamsted Research uses the mean temperatures over January and February to predict first flights and numbers by 1st July (found at Aphid Forecast | Insect Survey). The 2026 predictions are:

Rose-Grain aphid (Metopolophium dirhodum):

  • First flight prediction: 17th May for Edinburgh and 27th May for Dundee 
  • Predicted total numbers by 1st July: 40 individuals for Edinburgh and 27 for Dundee
     

Grain aphid (Sitobion avenae):

  • First flight prediction: 22nd May for Edinburgh and 29th May for Dundee. 
  • Predicted total numbers by 1st July:  25 individuals for Edinburgh  and 24 for Dundee.
     

Bird Cherry-Oat aphid (Rhopalosiphum padi):

  • First flight prediction: 11th May for Edinburgh and 16th May for Dundee.
  • Predicted total numbers by 1st July: 56 individuals for Edinburgh and 46 for Dundee.

Cereal aphids and PVY transmission in 2025 into 2026

  • In 2025, cereal aphids arrived early and in high numbers after an unusually warm spring. Although numbers did not reach average July peaks and the final seasonal totals were below average, high numbers were caught when crops were most vulnerable.

  • This means PVY spread was still a significant risk in 2025, and the anticipated incidence of plants showing mosaic symptoms remained relatively high.

  • In 2026, aphid activity is expected to be closer to the seasonal average, especially in Dundee. However, growers should be vigilant towards aphid activity and sources of virus during the 2026 summer due to the level of inoculum present and the risk of potential extreme weather.

  • Potato varieties that have shown a higher risk of acquiring PVY include King Edward, Harmony, Shepody, Maris Peer and Nicola.

Cereal aphids in 2026:

As the Inverness trap only started trapping in April 2019 and the Ayr trap has data gaps over the last 10 years, we currently report on Edinburgh and Dundee catches only.

  • Cereal aphid activity started around one week later than average, with most first catches happening around mid-May. The grain aphid (Sitobion avenae) was the exception which arrived three (3) weeks earlier than predicted on 30th April at Gogarbank.

  • Despite the unsettled spring weather and their late arrival, trap data now suggests the cereal aphids are slightly ahead of average and the summer migration may peak before mid-July, around two (2) weeks early.

  • The graphs below show actual aphid numbers from the Edinburgh and Dundee suction traps on a log scale. This makes early-season changes easier to compare for species with high seasonal peaks.

Rose-Grain aphid in 2026:

The first Rose-Grain aphid (Metopolophium dirhodum) was caught in Edinburgh on 18th May, only one day earlier than predicted. The first Rose-Grain aphid caught at Dundee was on 21st May, six days earlier than predicted. 

The cumulative total as of 02 August is 2120 ranking 18th over the last 40 years of trapping. 

89% of the cumulative total has been caught at Dundee; 11% at Edinburgh. 

Metopolophium dirhodum graph

Grain aphid in 2026:

The first Grain aphid (Sitobion avenae) was caught in Edinburgh on 30th April and in Dundee on 29th May - around three weeks earlier than predicted at Edinburgh, but arriving exactly on its predicted date at Dundee. 

The cumulative total up to 02 August is 1716, ranking 12th over the last 40 years of trapping.

79% of this cumulative total was caught at Dundee; 21% at Edinburgh.

Sitobion avenae graph

Bird Cherry-Oat aphid in 2026:

The first Bird Cherry-Oat aphid (Rhopalosiphum padi) in 2026 was caught in Dundee on 21st May and in Edinburgh on 28th May.

The cumulative total up to 02 August is 123, ranking 36th out of the last 40 years.

72% of this cumulative total was caught at Dundee; 28% at Edinburgh.
 

Rhopalosiphum padi graph

Apple-Grass aphid in 2026:

The first Apple-Grass aphids (Rhopalosiphum oxyacanthae) were caught in Edinburgh on 18 May and in Dundee on 21 May.

The cumulative total up to 02 August is 15, ranking 39th out of the last 40 years.

33% of this cumulative total was caught at Dundee; 67% at Edinburgh. 

 

Rhopalosiphum oxy graph