Oak killer found in rhododendrons

gen as a Plrytophthorn species, have now found the same disease agent in Santa Cruz County rhododendrons. This suggests the disease agent could spread over long distances on ornamental plants, and that it may be able to infect other plants as well. The counties hardest hit by SOD have been Marin, Sonoma and Santa Cruz, but it is also present in Monterey, Napa, Santa Clara and San Mateo. UC Berkeley geographer Nina Maggi Kelly has been monitoring and mapping the infestations (see p. 9). The exact number of trees that have succumbed to SOD is unknown, but using field plots, aerial photography and satellite imagery, Kelly hopes to understand the overall impacts of the disease on oak forests and the surrounding communities. ”Never before have we experienced such a rapid death of oaks,” says Marin County horticulture advisor Pave1 Svihra. ”When symptoms start to manifest, it will last no more than 6 to 8 weeks, then the tree is gone.“