IF spring does not throw any abnormal conditions at us, aphids could be flying around two weeks earlier than they would be expected to historically, according to AHDB’s aphid service.

This is a reversal of last year’s cold weather, as unseasonably warm weather at the end of February this year has pushed winter temperatures up by around 1°C above the 30-year average temperature throughout

most of Britain.

Experts are now suggesting that first aphid flight may be about two weeks early, based on the forecasts gleaned from mean temperatures in January and February during the past 55 years.

The temperatures in January and February have the potential to ‘reset’ aphid activity each year, with temperatures in November/December or March/April having little apparent impact.

Sue Cowgill, who manages pest research at AHDB, said: “When it comes to the first aphid flights, temperatures in January and February are critical. The spell of unseasonably warm weather at the end of February, in particular, has really helped push aphid development along this year.”

Two forecasts are available – the one for cereals covers bird cherry-oat aphid, rose-grain aphid and grain aphid; while the other covers brassica and potato threats from the peach-potato aphid, potato aphid and mealy cabbage aphid.

The estimated date ranges for the first aphids to be caught at suction trap sites across Britain are detailed in the forecasts. However, there is considerable uncertainty associated with the forecast dates at specific sites. The main purpose of the forecasts is to indicate how the current season compares with the long-term average. The information can be used to help focus in-field monitoring efforts.

It is also important to note that some aphids overwinter in crops and are likely to be present before aphid flights commence.

The latest aphid forecasts, as well as information on how to sign up to receive Aphid News, are published on the AHDB website: ahdb.org.uk/aphid-news

The table gives information for myzus persicae, macrosiphum euphorbiae and brevicoryne brassicae