Phytophthora root rot and stem blight impacts greater than 100 of the hottest and generally grown panorama perennials and annuals, together with annual vinca, petunia, and daylily, all through the U.S. and worldwide. The finest technique is to keep away from introducing Phytophthoras into the panorama as a result of as soon as Phytophthora species are established, they’re unattainable to eradicate with out extraordinary measures which can be impractical or costly as a result of they will survive for a few years. Therefore, resistant crops are the subsequent most suitable choice, however there may be restricted info on which plant species or cultivars make for appropriate replacements for infested panorama beds.
How We Determined Phythophthora Resistance
In 2018, we evaluated one to a few cultivars every of 15 annual and 12 herbaceous perennial plant species in every of three panorama beds in North Carolina. After crops had been established, every mattress was inoculated with three species of Phytophthora generally discovered affecting ornamentals in North Carolina: P. dreschleri, P. nicotianae, and P. tropicalis.
Plants had been evaluated for look and illness presence each two weeks. Known inclined crops reminiscent of gerbera daisy, petunia, dusty miller, and annual vinca had been planted in every mattress to make sure inoculum was energetic. All inclined crops died from Phytophthora by the finish of the season.
At the finish of the season, we recognized 14 cultivars amongst 9 annual plant species and eight cultivars amongst six herbaceous perennial plant species that had been rated as wonderful or good all through the rising season.
Other crops rated as honest or poor had been affected by different illnesses both recognized or not recognized together with Verticillium wilt, Phytophthora, Fusarium, powdery mildew, or abiotic illness of unknown origin. More outcomes are posted on the Meadows Plant Pathology Lab website.
This analysis was supported by a grant from the Horticultural Research Institute (HRI). Its contents are solely the accountability of the authors and don’t essentially characterize the views of HRI.