Elucidating the Spread and Transmissibility of Blueberry Mosaic Virus, a New Disease of Blueberry in the Southeastern U.S.

Final Report for OS13-076

Project Type: On-Farm Research
Funds awarded in 2013: $15,000.00
Projected End Date: 12/31/2016
Region: Southern
State: Kentucky
Principal Investigator:
Dr. Nicole Ward Gauthier
University of Kentucky
Expand All

Project Information

Abstract:

After the first year of the project, there were major changes to the grower farm, and thereby to the scope of the project. Unfortunately the blueberry grower (location of BIMaV infected plants) destroyed all plants and sold the farm.  Because this project was based on a new (first report) disease for the SSARE region, the project did not follow the original proposal.

After Year 1 of the project, however, we determined several details about the virus. First, our analysis by qPCR determined that most plants within the field were infected, including asymptomatic bushes (those without symptoms, healthy appearance).  Next, our collaborating virologists, in their 2014 manuscript, characterized BIMaV as an ophiovirus, which is transmitted by soilborne parasites.  Both chytrids (true fungi) Olpidium spp. and polymyxa (protists) Polymyxa spp. and Spongospora sp. were found to transmit the virus.  Briefly, both vector groups are obligate (cannot survive without hosts), intercellular parasites of roots that produce motile zoospores.  Zoospores do not move far from host roots, and primary movement is extremely slow.  Thus, we have determined that natural virus movement is unlikely, even within a field planting.  Unless blueberry plants are positioned with overlapping roots, spread throughout a field can take decades.  It is then most likely that the virus spreads more rapidly through cuttings and movement of whole plants.  We determined that our cooperating grower obtained infected plants when establishing his orchard.  Virus details and findings are published in “A new ophiovirus is associated with blueberry mosaic disease by T. Thekke-Veetil et. al. 2014.”

During Year 2 of the project, we requested an alternative project scope and submitted a budget revision to reflect loss of the experimental farm and the new research findings. Overall, this virus BIMaV, like many diseases of blueberry of small fruit, are best managed by cultural practices, especially sanitation.  Thus, we revised our budget and objectives to increase disease-management outreach to assist blueberry growers and other fruit growers within the SSARE region with virus and disease management.

We created educational materials to produce fact sheets and video tools for Extension agents/educators, commercial growers, and residential hobbyists. Additionally we extended pest management and IPM training to a broader group of growers within the state by sponsoring educational events and workshops.  Finally, we surveyed blueberry growers for suspect infections and confirmed that, besides the test farm, BIMaV was only present in one other location in Kentucky. 

Project Objectives:

Objectives of this revised project included:

  • Survey blueberry growers in Kentucky and determine whether there were other cases of BIMaV in the state.
  • Expand disease management outreach to growers of blueberry and other fruit crops in Kentucky.  Shift focus to include sustainability and low-input disease-management strategies.
    • Develop a series of videos for online training - appropriate for county agents/educators, commercial growers, and backyard hobbyists
    • Develop a series of disease management fact sheets and publications that include a focus on cultural practices (as explained through pathogen biology), giving growers a better understanding of management options and approaches.

Research

Participation Summary
1 Farmer participating in research

Educational & Outreach Activities

Participation Summary:

Education/outreach description:

Research Reports and Journal Submissions

  • Gauthier, N. A., Polashock, J., Thekke-Veetil, T., Martin, R. R., Beale, J. 2014.  First report of blueberry mosaic disease caused by blueberry mosaic associated virus in Kentucky. Plant Disease.
  • Fulcher, A., Ward Gauthier, N., Klingeman, W. E., Hale, F., White, S. A. 2014. Blueberry culture and pest, disease, and abiotic disorder management during nursery production in the Southeastern US: A review. Journal of Environmental Horticulture.

eXtension Submissions

  • Ward Gauthier, N., Koester, D., Tewksbury, F. 2014.  Vineyard Sanitation for Pest Control.  Grape Communities of Practice.
  • Ward Gauthier, N., Sears, A. 2014.  Managing Diseases without Fungicides – A Focus on Sanitation. Garden Professors series, Consumer Horticulture Community of Practice.

Extension Fact Sheets and Outreach Publications (http://www2.ca.uky.edu/agcollege/plantpathology/extension/pubs.html#Smallfruit)

  • Commercial Fruit Pest Management Guide - Annual spray guide, Midwest Fruit Workers project, added cultural practices and low input options.
  • Fruit, Orchard, and Vineyard Sanitation.
  • Midwest Blueberry Production Guide (edited and published at UK) - new publication, focus on plant health and cultural practices.
  • Backyard Fruit Disease Management Using Cultural Practices (with low spray, not spray, and organic options) - co-sponsored by UK SARE funding, series of four guides to cover apple, peach, grape, brambles, strawberry, and blueberry.

 

 

Project Outcomes

Project outcomes:
    • Agent In-Service, Organic and Sustainable Approach training 2015- Attendees expressed a 41% increase in understanding of organic and sustainable approaches fruit and vegetable gardening/production and anticipated being 50% better able to assist stakeholders after the training. Agents indicated that the new knowledge would be utilized to advise stakeholders, in county trainings, and in newsletters.
    • Blueberry School survey 2013 and 2015 - Growers reported an increase in understanding of more than 30% in plant disease management, insect management, weed management, fertility and composting, and organic certification.
    • KY fruit grower survey 2014 – Survey results indicated an overall 34% increase in profit and 43% increase in fruit quality as a result of Extension-related trainings and resources.  Overall, 56% of growers reported that they consulted university Extension specialists/agents when making pest-management decisions, 60% consulted Extension publications, and 51% utilized weather prediction models.
Any opinions, findings, conclusions, or recommendations expressed in this publication are those of the author(s) and do not necessarily reflect the view of the U.S. Department of Agriculture or SARE.