Almeida R P P, Wistrom C, Hill B L, Hashim J, Purcell A H
Department of Plant and Environmental Protection Sciences, University of Hawaii at Manoa, Honolulu 96822.
Department of Environmental Science, Policy, and Management, University of California, Berkeley 94720.
Plant Dis. 2005 Apr;89(4):419-424. doi: 10.1094/PD-89-0419.
Homalodisca coagulata (Say) is a sharpshooter leafhopper vector of the bacterial plant pathogen Xylella fastidiosa. Introduced into California about 15 years ago, this insect triggered recent outbreaks of Pierce's disease of grapevine in the state. H. coagulata has been observed feeding on dormant grapevines during the winter, raising the possibility of X. fastidiosa transmission during that season. We tested whether H. coagulata can acquire X. fastidiosa from and inoculate the bacterium to dormant grape (Vitis vinifera) in the laboratory and in the field. Usually, >90% of H. coagulata survived on dormant plants in the laboratory and field. Field experiments showed that H. coagulata can inoculate X. fastidiosa into dormant plants, yet field acquisition experiments did not result in transmission. Transmission to dormant plants during the winter is a potential problem in California vineyards adjacent to citrus groves or other habitats with large overwintering populations of H. coagulata. Because dormant plants have positive root pressure, our findings provide evidence that X. fastidiosa transmission does not require negative pressure in plant xylem to be inoculated into plants.
葡萄叶蝉（Homalodisca coagulata (Say)）是细菌性植物病原体木质部难养菌（Xylella fastidiosa）的一种叶蝉传播媒介。大约15年前被引入加利福尼亚州，这种昆虫引发了该州近期葡萄皮尔斯病的爆发。有人观察到葡萄叶蝉在冬季以休眠葡萄藤为食，这增加了该季节木质部难养菌传播的可能性。我们在实验室和田间测试了葡萄叶蝉是否能从休眠葡萄（欧亚葡萄）获取木质部难养菌并将其接种到休眠葡萄上。通常，在实验室和田间，超过90%的葡萄叶蝉在休眠植物上存活。田间试验表明，葡萄叶蝉能将木质部难养菌接种到休眠植物上，但田间获取试验并未导致传播。在加利福尼亚州与柑橘园或其他有大量葡萄叶蝉越冬种群的栖息地相邻的葡萄园，冬季向休眠植物的传播是一个潜在问题。由于休眠植物有正向根压，我们的研究结果提供了证据，证明木质部难养菌的传播不需要植物木质部的负压就能接种到植物中。
