RASPBERRY ROOT ROTS IN THE PACIFIC NORTHWEST

Root necrosis, wilting of primocanes, and premature senescence of floricanes are symptoms associated with root rot in the Pacific Northwest.
The fungus Phytophthora erythroseptica, the root lesion nematode Pratylenchus penetrans, and tomato ringspot virus vectored by Xiphinema americanum can each cause some of these symptoms.
At the Southwestern Washington Research Unit, Vancouver, where the population of P. penetrans was very low and Xiphinema spp. were not detected, twice yearly soil drench applications of the fungicide Ridomil (CGA-48988) effectively controlled root rot caused by P. erythroseptica in new and established plantings of ‘Willamette’ red raspberry.
Control of root rot persisted for at least one year after applications were discontinued.
At this location the nematicide Nemacur had no effect on the disease, and in a greenhouse test P. penetrans was unaffected by Ridomil.
Of nineteen fields where root rot was suspected nine had P. penetrans populations above 900 nematodes per 500 cc of soil and Xiphinema spp. were detected in 10 fields.
Ridomil reduced the incidence of primocane wilting in several of these fields but only in those where the population of P. penetrans was low.

Symposium on Breeding and Machine Harvesting of Rubus

P.R. Bristow

https://doi.org/10.17660/ActaHortic.1980.112.4