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John R. Yeo, Jerry E. Weiland, Dan M. Sullivan, and David R. Bryla

Phytophthora cinnamomi is a highly virulent root rot pathogen of highbush blueberry and is present in most growing regions worldwide ( Strik and Yarborough, 2005 ; Zentmyer, 1980 ). Symptoms of infection include poor shoot growth, root necrosis

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Kyle E. LaPlant, Gregory Vogel, Ella Reeves, Christine D. Smart, and Michael Mazourek

are cultivated for food as immature fruit (summer squash) and mature fruit (winter squash and processing pumpkins), and they are also grown for fall decorations, such as jack-o’-lanterns and gourds ( Paris, 2016 ). Phytophthora crown and root rot

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Ariadna Monroy-Barbosa and Paul W. Bosland

New Mexico ( Leonian, 1922 ). This pathogen can completely devastate a field of chile peppers ( Sanogo and Carpenter, 2006 ). The pathogen causes multiple disease syndromes such as phytophthora root rot, fruit rot, stem blight, and foliar blight ( Sy

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Benjamin K. Hoover and R.M. Bates

drained soils, PRR is the limiting factor in fraser fir production and is the only serious disease affecting fraser firs in Pennsylvania. Multiple species of Phytophthora are known to contribute to root rot in fraser fir ( Benson et al., 1976 ; Kuhlman

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Benjamin K. Hoover and R.M. Bates

.M. Sellmer, J.C. Despot, D.A. 2004 Postharvest characteristics of canaan fir and fraser fir Christmas trees HortScience 39 7 1674 1676 Benson, D.M. Grand, L.F. Suggs, E.G. 1976 Root rot of fraser fir caused by Phytophthora drechsleri Plant Dis. Rptr. 60 3

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John R. Yeo, Jerry E. Weiland, Dan M. Sullivan, and David R. Bryla

Phytophthora cinnamomi Rands is a soilborne pathogen that causes root rot in >900 plant species worldwide, including northern highbush blueberry ( Zentmyer, 1980 ). Currently, there are two groups of fungicides (phenylamides and phosphonates

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Charles S. Krasnow, Andrew A. Wyenandt, Wesley L. Kline, J. Boyd Carey, and Mary K. Hausbeck

Phytophthora crown and root rot is a destructive disease of pepper that causes significant annual losses throughout the United States ( Hausbeck and Lamour, 2004 ; Ristaino and Johnston, 1999 ). Michigan and New Jersey are important producers of

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David R. Bryla and Robert G. Linderman

the study was started. Thus, any Phytophthora and Pythium spp. infecting the roots probably originated with the planting stock. It should not be discounted, however, that ‘Duke’ is highly susceptible to root rot and therefore could develop

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Stephen L. Krebs and Michael D. Wilson

Fifty-seven rhododendron cultivars (genus Rhododendron L.) were screened for resistance to root rot caused by Phytophthora cinnamomi, using two levels of inoculum. While a majority (77%) of genotypes was susceptible, six cultivars had moderate resistance, and seven cultivars exhibited a high level of resistance to the disease. In these resistant groupings, the severity of root rot did not increase significantly with a 3-fold increase in inoculum. Comparisons of micropropagated and conventionally propagated plants revealed no significant difference in root rot ratings. The species R. keiskei was identified as a possible source of resistance to P. cinnamomi in two of the rhododendron cultivars.

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M.A. Ellis and S.A. Miller

A commercially available serological assay kit (flow-through enzyme-linked immunosorbent assay, Phytophthora F kit) was compared to a culture-plate method for detecting Phytophthora spp. in apparently diseased (phytophthora root rot) and apparently healthy red raspberry (Rubus idaeus subsp. strigosus Michx.) plants. During 4 years of testing, 46 tests were conducted on apparently diseased roots. All diseased plants gave a strong positive reaction, a result indicating that Phytophthora spp. were present. Of the 46 plants that tested positive, Phytophthora spp. were recovered from all but one using a selective medium for Phytophthora and the culture-plate method. When the same test was conducted on 27 apparently healthy plants, all had a negative reaction for the presence of Phytophthora except one sample, which had a slight positive reaction. No Phytophthora spp. were isolated from any apparently healthy plants. Our results indicate that the serological test kit enables rapid, dependable, on-site diagnosis of raspberry phytophthora root rot.