02306nas a2200205 4500008004100000022001400041245012500055210006900180260002900249300001400278490000700292520164900299100001701948700001601965700001201981700001501993700001502008700002202023856005502045 2011 eng d a1439-032900aPotential susceptibility of Australian flora to a NA2 isolate of Phytophthora ramorum and pathogen sporulation potential0 aPotential susceptibility of Australian flora to a NA2 isolate of bBlackwell Publishing Ltd a305–3200 v423 a

Phytophthora ramorum is an invasive plant pathogen and the cause of considerable and widespread damage in nurseries, gardens and natural woodland ecosystems of the USA and Europe. It is considered to be a significant plant disease as it could cause biodiversity loss and severe economic losses in plant industries in areas where it is not yet known to exist, such as Australasia. Foliar susceptibility and sporulation potential were tested using detached-leaf assays for 70 Australian native plant species sourced from established gardens and arboreta in California using a NA2 isolate of P. ramorum. Correa ’Sister Dawn’, Eucalyptus regnans, Isopogon cuneatus, I. formosus, Leptospermum scoparium, L. lanigerum and Melaleuca squamea were identified as potentially highly susceptible host species. Hedycarya angustifolia, Olearia argophylla, Phyllocladus aspleniifolius, Pittosporum undulatum and Podocarpus lawrencei were identified as potentially resistant. All 70 species were able to be infected with P. ramorum, as confirmed by reisolation. Putative sporulating hosts include five members of the Myrtaceae, Agonis flexuosa, Corymbia ficifolia, Eucalyptus haemastoma, E. delegatensis and E. viminalis. As a part of a precautionary strategy, the potentially highly susceptible species found in this study are suitable candidates for targeted surveillance programmes in high-risk incursion areas of Australia and within the global horticultural trade.

1 aIreland, K B1 aHüberli, D1 aDell, B1 aSmith, I W1 aRizzo, D M1 aHardy, St., G E J uhttp://dx.doi.org/10.1111/j.1439-0329.2011.00755.x