Assessing risk of False Blossom Disease and vector introduction and establishment to Washington and Oregon Cranberry Producing Regions

Project Overview

Project Type: Professional + Producer
Funds awarded in 2024: $74,527.00
Projected End Date: 03/31/2027
Grant Recipient: Washington State University
Region: Western
State: Washington
Principal Investigator:
Dr. Laura Kraft
Washington State University


  • Fruits: berries (cranberries)


  • Pest Management: disease vectors, field monitoring/scouting, prevention

    Proposal abstract:

    Preventing the introduction and establishment of an invasive
    species is more cost-efficient and environmentally sustainable
    than attempts to manage it later. The phytoplasma called False
    Blossom Disease threatens cranberries on the East Coast and in
    Wisconsin. This disease results in stunted flowering that causes
    permanent yield loss in these perennial plants, which must then
    be removed. False Blossom Disease (FBD) can be spread either
    through nursery cuttings, like those used to replant or
    ‘renovate’ a cranberry bog, or via an insect vector, the Blunt
    Nose Leafhopper. Currently, there are no recorded cases of FBD on
    the West Coast (United States and Canada) but it is uncertain if
    the insect vector already exists here.

    We propose an intensive sampling program of the major cranberry
    growing regions in Washington and Oregon to scout for the vector.
    If found, or if bogs contain symptoms of FBD, then we will use a
    nested PCR design to test for FBD.

    During sampling, we will work with growers in Washington and
    Oregon to educate them on the disease and its identification as
    well as to provide growers with guidance on how to prevent this
    disease-pest system from spreading to the West Coast, by
    attempting to change renovation practices whereby growers
    purchase untested vines from Wisconsin and New Jersey. To
    evaluate our program, we have designed a pre- and post-test on
    knowledge of false blossom disease, a pre-/post-survey and a
    pre-/post-focus group on behaviors and attitudes towards
    renovation practices and prevention of spread of this disease.

    Project objectives from proposal:

    Research Objective 1. Characterize and determine relative
    abundance of leafhoppers, including the blunt-nose leafhopper, in
    Washington and Oregon cranberry growing regions.
    each bog sampled, we will measure leafhoppers from samples to
    genus noting diversity and abundance. Samples can be kept in 70%
    ethanol almost indefinitely which will allow us to quantify
    samples in winter once field work has been completed. Samples
    will be taken and quantified during 2024 and 2025.

    Research Objective 2. Determine if false blossom disease
    is present in cranberry bogs that have the blunt-nose leafhopper
    and/or vines with symptoms similar to false blossom with
    molecular diagnostic assays.
     All bogs with BNLH
    present or with symptoms will be tested for presence/absence of
    FBD phytoplasma using a nested PCR diagnostic test by the USDA
    team that has experience with plant pathology testing. Any
    necessary sampling and testing will be done in field seasons
    2024-2026 depending on when BNLH or FBD symptoms are found.

    Educational Objective 1. Improve grower knowledge of
    False Blossom Disease, its symptoms, its potential economic
    effects to the region, and where it is currently found (including
    updated research from the survey of West Coast bogs).
    will use a pre/post-test, which Kraft frequently uses to assess
    knowledge gain to capture this output. The pre-test will be
    handed out in 2024 at the start of the project while the
    post-test will be taken in winter 2025-2026 at the culmination of
    the project.

    Educational Objective 2. Design a survey tool and host
    informal focus groups in each region during their regular annual
    meetings to discuss the threat of FBD and determine behavior and
    attitudes at the start and end of the program.
    survey will specifically focus on questions regarding behavior
    and attitudes as written in collaboration with a social scientist
    on another project and will capture measurable change in
    behaviors and attitudes when used twice as a pre/post-survey. We
    will give growers the survey in winter 2023-2024 before this
    project would start and again in spring/summer 2026 when the
    project wraps up.

    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.