Potential of strawberry aphids control by parasitoids

In Belgium, three main species of aphids, Rhodobium porosum, Chaetosiphon fragaefolii and Aulacorthum solani can be present simultaneously and provoke huge losses in strawberry crops. The aim of the present work was to compare the activity and parasitism rates of seven species of Hymenoptera parasitoids to analyse their biocontrol potential on each aphid species. Using video recording of their behaviour, we first determined the acceptance of host aphid by parasitoids based on the numbers of antennae contacts followed by ovipositor contact, aphid survival, numbers of mummies produced and rate of parasitoids emergence under standardized conditions. We also determined the parasitism rate after a 24 h contact with 100 aphids. Finally, cage experiments under glasshouses conditions were done to assess the control capacities of selected parasitoids Aulacorthum solani was parasitized by Aphidius ervi, Aphidius matricariae, Ephedrus cerasicola and Praon volucre with parasitism rates ranging from 24% to 51%. Rhodobium porosum was only parasitized by A. ervi and Aphelinus abdominalis at a rate from 1.6 to 7% while C. fragaefolii was parasitized by P. volucre and E. cerasicola. Cage experiments showed that the parasitoid species selected on the basis of these experiments are well able to significantly reduce the aphid population