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ARS Home » Pacific West Area » Corvallis, Oregon » Horticultural Crops Research Unit » Research » Publications at this Location » Publication #317975
Title: Root removal to improve disease management in replanted Washington red raspberry fields

Author
item Weiland, Gerald - Jerry
item Zasada, Inga
item DEVETTER, LISA - Washington State University
item WALTERS, THOMAS - Washington State University Extension Service
item RUDOLPH, RACHEL - Washington State University
item WATKINSON, SEAN - Washington State University

Submitted to: American Phytopathological Society Annual Meeting
Publication Type: Abstract Only
Publication Acceptance Date: 3/25/2015
Publication Date: 11/1/2015
Citation: Weiland, G.E., Zasada, I.A., Devetter, L.W., Walters, T., Rudolph, R., Watkinson, S. 2015. Root removal to improve disease management in replanted Washington red raspberry fields. American Phytopathological Society Annual Meeting, August 1-5, 2015, Pasadena, California.

Interpretive Summary: Washington leads the nation in the production of red raspberries for processing. Soilborne pathogens (certain types of nematodes and fungi) are a production constraint in this $61 million industry with growers relying on soil fumigation for their management. However, current fumigation methods can be ineffective, leading to replant disease issues and decreased crop lifespan. It is suspected that residual root debris remaining in the field after destroying the previous crop serves as a refuge protecting pathogens from lethal doses of fumigant. Residual roots would therefore act as a bridge for reintroducing pathogens to young raspberry plants in replanted fields. In 2014, three root removal devices were tested for their ability to remove roots from fields slated for fumigation and replanting. All three devices were equally effective and lifted about 95% of residual roots. A field trial was then implemented to look at the effect of fumigation alone, root removal alone, and a combined treatment with both root removal and fumigation on reducing pathogen populations. No treatment was effective at reducing nematode populations. However, both root removal alone and fumigation alone reduced fungal pathogen populations, with the combined root removal + fumigation treatment providing the best control and reducing soil populations by 64 and 69%, respectively.

Technical Abstract: Washington leads the nation in the production of red raspberries for processing. Soilborne pathogens are a production constraint in this $61 million industry with growers relying on preplant soil fumigation for their management. However, current fumigation methods can be ineffective, leading to replant issues and decreased crop lifespan. It is suspected that residual root debris remaining in the field after destroying the previous crop serves as a refuge protecting pathogens from lethal doses of fumigant. Residual roots would therefore act as a bridge for reintroducing pathogens to young raspberry plants in replanted fields. In 2014, three root removal devices (a Lundeby plant lifter, a potato harvester, and a beach cleaner) were tested for their ability to remove roots from fields slated for fumigation and replanting. All three devices were equally effective and lifted about 95% of residual roots, but the potato harvester was fastest. A field trial was then implemented with fumigation as the main plot and root removal as the subplot to determine the effect of root removal on reducing pathogen populations. Ten weeks after root removal and fumigation, no treatment was effective at reducing Pratylenchus penetrans populations. However, both root removal alone and fumigation alone reduced Fusarium and Pythium populations, with the combined root removal + fumigation treatment providing the best control and reducing soil populations by 64 and 69%, respectively.