Item

Land-use changes influence the sporulation and survival of Phytophthora agathidicida, a lethal pathogen of New Zealand kauri (Agathis australis)

Lewis, KSJ
Black, Amanda
Condron, LM
Waipara, NW
Scott, P
Williams, Nari,
O’Callaghan, M
Date
2019-02-14
Type
Journal Article
Fields of Research
ANZSRC::3007 Forestry sciences , ANZSRC::3108 Plant biology
Abstract
Phytophthora agathidicida is the accepted causal agent of dieback in remnant stands of long-lived indigenous New Zealand kauri (Agathis australis) and poses a significant threat to the long-term survival of this species. Little is known about the effect of key soil physicochemical characteristics on the growth of P. agathidicida. In this study, we investigated the growth of P. agathidicida in soils collected from adjacent areas under original kauri forest, short rotation pine (Pinus radiata) plantation forest and grazed pastures. A growth response assay was used to quantify asexual (sporangia) and sexual (oospore) spore counts over 8 days in soils sampled from each land-use. Significantly higher numbers of sporangia (p < 0.001) and oospores (p < 0.01) were found in pasture and pine forest soil within 2 days of the growth assay trials, suggesting these soils may favour asexual/sexual reproduction in the early stages of P. agathidicida establishment compared to kauri forest soils. Additionally, oospore production significantly increased over 8 days in pine forest soil, suggesting that with an increase in inoculum loads, these soils potentially act as pathogen reservoirs. The soil physicochemical properties (e.g., pH, C and N, phosphorus content and electrical conductivity) investigated in this study did not significantly correspond to spore count data between land-uses, suggesting that differences in growth response are driven by other edaphic factors not explored in the present study.
Rights
© 2019 Blackwell Verlag GmbH
Creative Commons Rights
Access Rights