Factsheet DSS carrot rust fly

Carrot rust fly is an insect that can cause damage to carrots and some other crops. The first generation of adult carrot fly emerge from pupae in the soil in the spring, and lay eggs close to the base of vulnerable crops. Larvae initially feed at the surface, then tunnel into the tap root. Adults emerge mid-July and can lead to a second generation. Treatments may need to be applied soon after adults arrive in the crop, before larvae tunnel into the crop roots. The DSS determines the start of the flight period for the 1st generation of carrot rust fly based on accumulated degree-days (260 day-degrees) over a base temperature of 5°C. The model uses daily air temperature; the default starting day is 1 March. Please adapt if necessary for your country. Be aware that in areas with field covers (plastic, single or double non-woven covers, etc.) with early crops the preceding season (either on the current field or neighbouring fields), the flight period can start earlier than predicted due to higher soil temperature under the covers. The DSS shows accumulated day degrees after 1 March and thresholds for the start of the flight period and the threshold for the peak of the flight period. When the first flight is expected, placing yellow sticky traps in the field is recommended to monitor if the flies indeed are present in the field. The DSS was developed by Luke, Finland, and is considered applicable, but not yet validated, in the United Kingdom, Belgium, The Netherlands, France, Germany, Luxembourg and Denmark.