Pest insects in carrot and Apiaceous crops: monitoring and forecasting carrot flies

Learn about monitoring and forecasting carrot fly to get on top of crop infestations before it’s too late. 
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Monitoring carrot fly

You can use orange sticky traps to monitor adult carrot fly numbers in susceptible cropsAngle your traps at 45° to the vertical. They will then become very selective for carrot flies, which prefer to land on the lower surface. 

Studies have shown that carrot fly numbers and subsequent damage are at their highest close to field margins and that fly numbers decrease quite rapidly a short distance into the crop. Consider that when placing your sticky traps. 

Treatment thresholds have not been established in the UK. 

Graph comparison of observed (trap captures) and forecast carrot fly activity in 2015 at Wellesbourne.

Forecasting carrot fly

The timing of the various stages in the carrot fly life cycle can be predicted using a computer program developed with funding from Defra and AHDB. The output from this program is currently available as part of the AHDB Pest Bulletin. The forecast indicates when flies of each generation will emerge from pupae and when they will lay eggs. 

Useful links

Find out how to reduce the impact of carrot fly Download the full report: Pest insects infesting carrot and other Apiaceous crops Read the Carrot & Parsnip Crop Walkers' Guide

If you would like to order a hard copy of the Carrot & Parsnip Crop Walkers' Guide, please contact or call 0247 799 0069.

Content for this web page was originally authored by Rosemary Collier, University of Warwick.

Dawn Teverson

Knowledge Exchange Manager - Field Vegetables (Alliums, Brassicas, Carrots, Legumes)