Susceptibility levels of Rhododendron species and hybrids to Phytophthora ramorum

Abstract

Until now there has been little scientific information available about the susceptibility of different Rhododendron species and cultivars to Phytophthora ramorum. However, growers could use this knowledge as part of their control strategy. In our susceptibility screening we first optimized different inoculation methods on stem and leaf material. Four methods were chosen for the actual screening: two on detached leaves and two on detached stems, each time involving either wounded or non-wounded tissues. Finally, 63 Rhododendron species and hybrids were screened and the correlation between the different inoculation methods was investigated. Inoculation methods involving wounding revealed limited differences in susceptibility between the species and hybrids. However, inoculation methods on non-wounded tissues showed a larger degree of variation in susceptibility. This suggests that when some form of resistance is present, it probably takes place at the level of tissue penetration.

Parent Publication

• Proceedings of the sudden oak death second science symposium: the state of our knowledge

Citation

De Dobbelaere, Isabelle; Heungens, Kurt; Maes, Martine. 2006. Susceptibility levels of Rhododendron species and hybrids to Phytophthora ramorum. In: Frankel, Susan J.; Shea, Patrick J.; and Haverty, Michael I., tech. coords. Proceedings of the sudden oak death second science symposium: the state of our knowledge. Gen. Tech. Rep. PSW-GTR-196. Albany, CA: Pacific Southwest Research Station, Forest Service, U.S. Department of Agriculture: 79-81