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Poster: Diseases of Plants: New & Emerging Diseases


The impact of laurel wilt caused by Raffaelea lauricola on clonal populations of pondberry (Lindera melissifolia)
S. BEST (1), S. Fraedrich (1) (1) USDA Forest Service, Athens, GA, U.S.A.

Pondberry is a rhizomatous, clonally reproducing, woody shrub species that is federally endangered. Like other members of the Lauraceae that occur in the United States (US), pondberry is highly susceptible to laurel wilt, a disease caused by Raffaelea lauricola and vectored by the redbay ambrosia beetle (Xyleborus glabratus). A study was initiated in 2012 to assess the potential impact of the disease on clonal populations of pondberry. Individual pondberry plants were planted in nursery beds near Athens, Georgia and grown for approximately 3 years, and during this time individual plants produced many ramets. The original plant in two populations were inoculated with R. lauricola in July, 2015 and plants were monitored regularly. After 12 wk, 55 ramets died in one population at distances up to 172 cm from the original inoculated plant, and in the other population 22 ramets died at distances up to 337 cm. R. lauricola was reisolated from 84% of the wilted ramets. The study confirms that pondberry is highly susceptible to laurel wilt and that the disease can spread rapidly through rhizomes of infected plants. Although pondberry is a small shrub that is not often attacked by X. glabratus, when infections occur they could be detrimental to populations. Additional studies are being conducted to examine the feasibility of using trenching around infected plants to prevent disease transmission, and the use of chemicals to protect plants from infection.