Disease epidemiology and management of phytophthora root rot and wilt of red raspberry

R.R. Burlakoti, S. Sapkota
Phytophthora root rot and wilt (PRRW) caused by Phytophthora rubi is an economically important disease of red raspberry in Canada and other growing regions in the world. Large-scale field surveys were conducted in different raspberry fields from 2018 to 2020 to understand the prevelance of PRRW in British Columbia (BC), Canada. Three years (2020-2022) of field trials were also conducted in pathogen-inoculated microplots to evaluate different foliar (fosetyl-Al and phosphites) and soil-drench (oxathiapiprolin, metalaxyl-m, and cyazofamid) fungicides and their application timing for controlling PRRW. Weather variables, including temperature and rainfall, were recorded. PRRW disease symptoms were found in all three years (2018-2020); however, the PRRW incidence in raspberry fields was higher in 2020 compared to 2018 and 2019. Disease incidence was higher in susceptible cultivars (‘Chemainus’, ‘Squamish’, ‘Meeker’, ‘Rudi’) than in the moderately resistant ‘Cascade Bounty’. Tank mix applications of oxathiapiprolin and metalaxyl-m alone or in combination with cyazofamid significantly increased (P<0.05) the number of primocanes and floricanes, floricanes weight, and fruit yield compared to controls. Our findings indicates that PRRW is a major problem of raspberry growers in BC, and applications of soil drench products with different modes of action were quite effective in reducing PRRW.
Burlakoti, R.R. and Sapkota, S. (2024). Disease epidemiology and management of phytophthora root rot and wilt of red raspberry. Acta Hortic. 1388, 217-222
DOI: 10.17660/ActaHortic.2024.1388.33
cyazofamid, fungicides, metalaxyl-m, oxathiapiprolin, phosphites, Phytophthora rubi, Rubus idaeus

Acta Horticulturae