EPPO Express Pest Risk Analysis Chaetosiphon fragaefolii Norway 2014

Pest risk analysis areas (PRA) were all strawberry producing areas in Norway, but especially coastal areas with mild winters and clusters of growers aiming to extend the season (e.g., Agder and Rogaland).

The tolerance level of 1% of plants harbouring C. fragaefolii makes the likelihood of entry with imported plants and establishment during the growing 
season very high. The likelihood of long-term establishment through several years is smaller. Still, if viruses are present in imported material together with C. fragaefolii, these viruses may be spread by winged aphids to other plantings before winter, regardless of the fate of the aphid population in winter. We perceive this mechanism as the greatest phytosanitary risk. Statistically, if 1 % of plants harbour virus, and 1 % aphids, 
one plant in every 10 000 plants will have both, and there will be 3 such double-infected plants per ha.

Importers/ growers should check imported plants for 
aphids throughout the season, and inspections from the National Food Authority should take place. A guideline for aphid management in imported plants, especially in protected crops, should be made. The aphidicides used at the export sites should be made known to the buyers to slow down resistance development. Buying CATT (Controlled Atmosphere Temperature Treatment) plants will probably lower the risk of introducing live aphids, especially in plants not subjected to long cold storage.

Bioforsk