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Mechanisms of woolly aphid [Eriosoma lanigerum (Hausm.)] resistance in apple

Sandanayaka, W.R.M., Bus, V.G.M., Connolly, P.
Journal of applied entomology 2005 v.129 no.9-10 pp. 534-541
cultivars, apples, germplasm evaluation, Eriosoma lanigerum, varietal resistance, resistance mechanisms, population growth, Malus domestica, insect development, insect reproduction, pest resistance, mortality
The sourcing of new resistant accessions and understanding their resistance mechanisms are significant aspects of a breeding strategy for durable resistance. Resistance of a number of apple accessions to the woolly apple aphid (WAA) [Eriosoma lanigerum (Hausm.)] was assessed based on the biological parameters of the insect. Two experiments were conducted under glasshouse conditions in two consecutive years during January-February of 2002 and 2003. In Expt 1 in 2002, settlement, development and survival of the aphids were assessed on five apple accessions [Roter Eiserapfel (RE), Freiherr von Berlepsch (FvB), Braeburn (B), Willie Sharp (WS) and Royal Gala (RG)]. RG was the most susceptible and WS the most resistant accession to WAA. RG and WS were included as references in Expt 2 in 2003, with 11 further accessions (Malus floribunda 821 OP (open-pollinated) G01-078 (MF), Korichnoe Polosatoje OP G01-104 (KP), Geneva (G), Raritan (R), Malus 6 (M-6), Twenty Ounce (TO), Winter Majetin (WM), Aotea (A), Irish Peach (IP), Court Pendu Plat (CPP) and Colonel Vaughan (CV). Daily reproductive rate and colony establishment were added to the three paramaters assessed in Expt 1. The overall results showed resistance in G, MF, WS and KP to settlement and development with low survival at the larval stage of the aphid, whereas R showed resistance in all the parameters tested. RG and CPP have proved to be susceptible while A, WM, TO, M-6, IP and CV were partially resistant.