The forecast outputs below are based on weather data collected by Plantsystems Limited and funded by Syngenta. The forecasts predict the timing of fly activity. They do not predict the number of insects present in the crop, as this depends on the size of the local fly population. For control purposes, we consider that the pest has become active when 10% of the insects have emerged/laid eggs and that the peak of activity has occurred when 50% have emerged/laid eggs. The predictions will change over time depending on weather conditions.

Updated 29 September 2022

Region	Second generation Forecast 10% EGG-LAYING in 2022	Second generation Forecast 50% EGG-LAYING in 2022	Third generation Forecast 10% EGG-LAYING in 2022	Third generation Forecast 50% EGG-LAYING in 2022
Cornwall (Newquay)	23 Jun	15 July	21 August	6 September
Kent (Canterbury)	6 Jul	23 July	7 September	17 September
Suffolk (Woodbridge)	21 Jun	13 July	8 August	5 September
Wellesbourne (Warwick)	24 Jun	13 July	8 August	5 September
Norfolk (Norwich)	27 Jun	19 July	19 August	6 September
South Lincolnshire (Boston)	30 Jun	29 July	26 August	10 September
Nottingham (Bilsthorpe)	1 July	29 July	28 August	18 September
Lancashire (Ormskirk)	8 Jul	30 July	4 September	20 September
York (Market Weighton)	8 Jul	5 Aug	4 September	21 September
Scotland (Blairgowrie)	10 Aug	30 Aug	-	-