Chemical control of Phytophthora ramorum
In Poland, the efficacy of 6 fungicides (phosetyl Al, furalaxyl, fenamidone + phosetyl Al, propamocarb + phosetyl Al, oxadixyl +mancozeb, cymoxanil + famoxate) against twig blight of rhododendron, caused by Phytophthora ramorum (EPPO Alert List), was assessed. Laboratory studies and glasshouses trials were conducted with artificially inoculated soils and plants, and the tested compounds were applied at a dose of 8 µg of a.s/cm². The inhibition of zoosporangia formation in treated soil extracts was recorded after 6 days of incubation in the laboratory. In glasshouse trials, the length and diameter of necrosis on stems and leaves was recorded at 7 and 14 days after inoculation. All tested compounds significantly inhibited the development of twig blight, but furalaxyl was found to be the most effective.
Sources
Orlikowski LB (2004) Chemical control of Rhododendron twig blight caused by Phytophthora ramorum.
Journal of Plant Protection Research, 44(1), 41-46.