Peach-Potato Aphid

  • The peach-potato aphid (Myzus persicae) is considered to be the most important aphid vector of potato viruses, especially potato leaf roll virus (PLRV).

  • In Scotland, the peach-potato aphid usually appears later and in lower numbers than in warmer countries, but mild winters can increase the risk of virus transmission seed potato crops.

  • Cold winters reduce survival and can delay aphid population build-up the following growing season. SASA predicts peach-potato aphid activity using the mean temperatures over December to February (which differs from Rothamsted who only use January & February mean temperatures).

Alate Myzus persicae

First flight predictions 2026

  • Winter 2025-26 was warmer than average in Edinburgh and close to average in Dundee; 4.98°C at SASA (Edinburgh; mean = 4.1°C) ranking 16th from the last 57 years and 3.7°C at JHI (Dundee; mean = 3.75°C) ranking 35th from the last 59 years.

  • Based on winter temperatures, SASA's predictions for the first flight of M. persicae is 29th May in Edinburgh and 11th June at Dundee (Table 1). This suggests activity may start about two (2) weeks earlier than average in Edinburgh and around average at Dundee.

  • SASA predicts the number of M. persicae caught by 31st July 2026 are 30 individuals at Edinburgh and 19 at Dundee. Although aphid numbers are expected to be below average, PLRV levels were above average in 2025, so potato leaf roll virus (PLRV) risk remains high.

  • Growers should remain vigilant and continue active virus management throughout the 2026 season.

Table 1 – Myzus persicae predictions 2026

M. persicae Dundee Edinburgh
First catch in 2026*

1 June

1 June
Predicted first catch in 2026 11 June 29 May
Average date of first Catch 11 June 12 June
Total catch to 31 July 2026

120

60
Predicted total catch to 31 July 2026 19 30
Average total catch to 31 July 57 34

*Date of first catch is provisional and may change due to incomplete catches from early in the season

Peach-potato aphids in Scotland 2026:

  • The first peach-potato aphids of 2026 were caught at both Edinburgh and Dundee on 1st June. This was slightly later than predicted, but about 10 days earlier than average at both sites. The timing was within the expected range range for a typical Scottish spring (based on our 75% confidence limits for each site).

  • As of 02 August 2026, 183 peach-potato aphids have been caught; 61 at Edinburgh and 122 at Dundee. This ranks 7th when compared to the last 39 years at this point of the season.

  • During week 27 July to 02 August 2026, 5 peach-potato aphids were caught; 1 at Edinburgh and 4 at Dundee.

The table below uses a logarithmic scale to make lower catches easier to compare with high-peak years such as 2023.

Myzus persicae weekly totals