The role of woolly apple aphids (<i>Eriosoma lanigerum</i>) at vectoring <i>Neonectria ditissima</i> conidia

Abstract

Colonies of woolly apple aphids (Eriosoma lanigerum) were sampled from canker lesions from apple orchards in Motueka New Zealand between February and April 2015 to determine their ability to vector the fungus Neonectria ditissima the causal organism of European canker Five percent of collected aphids carried N ditissima conidia Galls formed on young shoots by the feeding behaviour of these aphids also harboured symptomless infections of N ditissima (180) when such galls were incubated on apple sap amended water agar (ASAWA) Exposing some woolly apple aphids to N ditissima conidia contaminated glass slides for <2 min showed that 55 of the aphids were able to carry an average of 463 and up 184 conidia Approximately 125 of aphids were still found to carry viable conidia 10 days post contamination Woolly apple aphids might play a role in the epidemiology of N ditissima but their relative importance still needs investigation