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ARS Home » Pacific West Area » Salinas, California » Crop Improvement and Protection Research » Research » Publications at this Location » Publication #379283

Research Project: Management of Pathogens for Strawberry and Vegetable Production Systems

Location: Crop Improvement and Protection Research

Title: New techniques exploring relationships between pathogen pressure and disease progression in strawberry

item Matson, Michael
item HANG, MICHAEL - California State University
item PASTRANA LEON, ANA - University Of California
item CROUCH, UMA - Former ARS Employee
item Goldman, Polly
item Henry, Peter
item MELTON, FORREST - California State University
item Martin, Frank

Submitted to: American Phytopathological Society Annual Meeting
Publication Type: Abstract Only
Publication Acceptance Date: 3/25/2020
Publication Date: 8/10/2020
Citation: Matson, M.E., Hang, M., Pastrana Leon, A.M., Crouch, U., Goldman, P.H., Henry, P.M., Melton, F., Martin, F.N. 2020. New techniques exploring relationships between pathogen pressure and disease progression in strawberry. American Phytopathological Society Annual Meeting, August 10-14, 2020 (virtual).

Interpretive Summary:

Technical Abstract: Resurgences of soilborne diseases in strawberry production due to the phaseout of methyl bromide has necessitated a better understanding of how different levels of pathogen presence contribute to subsequent disease. We modeled the distribution of Verticillium dahliae microsclerotia (MS) prior to fumigation in a 10 acre field in Watsonville CA. 96 sample points were arranged in a grid, and samples were collected via pooling five individual subsamples originating from the center and edges of a 5 ft radius circle. Following fumigation, plant health was monitored by remote sensing drone flights and there was an end-of-season soil recollection of 36 soil samples to reassess pathogen presence and distribution. We identified a modest correlation between MS/g values and disease progression in prefumigation soil samples, but a poor correlation between end-of-season values and disease progression, likely due to low inoculum levels. A similar experiment in fields showing disease due to Fusarium oxysporum f.sp. fragariae utilized both direct plating colony counts and a new method for extracting DNA from large volume soil samples for the purpose of qPCR based prediction of CFU/g. These end-of-season soil samples showed a better correlation between measured CFU/g levels and remote sensing NDVI values than from V. dahliae. These results validate that pre-fumigation of modelling of pathogen distribution can predict subsequent disease severity, but that some pathogens can persist following fumigation to levels below meaningful detection thresholds while still contributing to disease.