Sources of inoculum for Phytophthora ramorum in a redwood forest
Sources of inoculum for Phytophthora ramorum in a redwood forest
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DOI：
10.1094/phyto-98-8-0860
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发表时间：
2008-08-01
期刊：
影响因子：
3.2
通讯作者：
Rizzo, D. M.
中科院分区：
文献类型：
--
作者：
Davidson, J. M.;Patterson, H. A.;Rizzo, D. M.
对红杉林中的疫霉 (Phytophthora ramorum) 的主要宿主接种物来源进行了调查。在实验室中对受感染的月桂树 (Umbellularia californica)、石栎 (Lithocarpus densiflorus) 和红杉 (Sequoia sempervirens) 的树干、树枝和/或叶子进行孢子囊生产测试。孢子囊发生在所有植物组织上，其中月桂叶和橡树小枝上的百分比最高。为了进一步比较这两个物种，在 2003-04 和 2004-05 雨季进行了接种物产量和感染的现场测量。两个季节中，月桂树的径流雨水和个体感染的接种量均显着高于茶橡树。 2004-05 年期间，当降雨持续到春季较长时，月桂树接种量的两次测量值均显着增加，而 tanoak 的接种量在这两年之间没有显着差异。 2003-04 年，Tanoak 树枝比月桂叶更容易被感染，2004-05 年也同样可能被感染。这些结果表明，红杉林中的大部分 P. ramorum 接种物是由月桂树叶上的感染产生的。长时间降雨的年份会增加塔诺橡树的风险，因为接种量较高，而且感染期会持续到春末。
Sources of inoculum were investigated for dominant hosts of Phytophthora ramorum in a redwood forest. Infected trunks, twigs, and/or leaves of bay laurel (Umbellularia californica), tanoak (Lithocarpus densiflorus), and redwood (Sequoia sempervirens) were tested in the laboratory for sporangia production. Sporangia occurred on all plant tissues with the highest percentage on bay laurel leaves and tanoak twigs. To further compare these two species, field measurements of inoculum production and infection were conducted during the rainy seasons of 2003-04 and 2004-05. Inoculum levels in throughfall rainwater and from individual infections were significantly higher for bay laurel as opposed to tanoak for both seasons. Both measurements of inoculum production from bay laurel were significantly greater during 2004-05 when rainfall extended longer into the spring, while inoculum quantities for tanoak were not significantly different between the 2 years. Tanoak twigs were more likely to be infected than bay laurel leaves in 2003-04, and equally likely to be infected in 2004-05. These results indicate that the majority of P. ramorum inoculum in redwood forest is produced from infections on bay laurel leaves. Years with extended rains pose an elevated risk for tanoak because inoculum levels are higher and infectious periods continue into late spring.