California Ag Network

Tag: Grapevine Leafroll Disease

  • Vine Mealybug Control in California Vineyards

    Vine mealybug (Planococcus ficus) has become one of the most economically damaging pests in California vineyards. Left unmanaged, infestations can reduce yield, weaken vines, lower sugar content and spread viruses like leafroll, which contribute to sudden grapevine collapse.

    The good news is effective control is possible with the right timing and integrated approach.

    In this guide, we break down proven strategies used by California growers to control vine mealybug based on field insights and expert interviews featured on the California Ag Network channel.

    What is Vine Mealybug?

    Vine mealybug is a small, sap-feeding insect that:

    ·      Hides under bark, in clusters and on roots

    ·      Produces sticky honeydew that attracts ants and encourages sooty mold

    ·      Reproduces rapidly in warm climates like California’s Central Valley

    Why it’s so dangerous?

    ·      Multiple generations per year.

    ·      Protected hiding spots make detection more difficult and contact sprays less effective.

    ·      Can vector or spread various vineyard diseases like grapevine leafroll disease and others.

    Signs of Vine Mealybug infestation

    ·      White, cottony masses under bark or on clusters

    ·      Sticky residue (honeydew) on leaves and fruit

    ·      Black sooty mold developing on vines

    ·      Increased ant activity (ants protect mealybugs)

    Ant presence is often your first indicator of vine mealybug. If you have ants in your vineyard, you probably have vine mealybug.

    So, you’ve scouted your vineyard and found vine mealybug: what next?

    Integrated Vine Mealybug Control Strategy

    The most effective approach combines timing, chemistry, biology and monitoring.

    ·      Dormant and early season control

    ·      Growth stage foliar sprays

    ·      Biological control (natural enemies)

    ·      Ant control

    ·      Monitoring and timing

    Dormant & Early Season Control

    Prevention is the best medicine. An insecticide spray during late dormancy or at bloom is usually enough to control their population all season long for milder infestations. There is a lot that goes into determining which chemistries to use such as soil conditions and specific regional climates. The UC Cooperative extension also recommends considering other pests in your treatment in strictly preventative situations. Broad spectrum pesticides can take care of more problems than just vine mealybug and reduce the number of passes through the vineyard. Be aware, however, that broad spectrum insecticides can also reduce beneficial insect populations so be sure to consult your Pest Control Advisor for the best dormancy and bloom treatments.

    Other helpful strategies include:

    ·      Remove loose bark to expose hiding populations

    ·      Apply delayed dormant insecticides if the pressure is high

    This stage is critical because you’re targeting populations before they explode

    In-Season Chemical Control

    While the vine mealybugs are developing, it’s essential to use systemic insecticides applied through drip irrigation where possible for the deepest control. Contact insecticides and foliar systemic sprays can contribute to control as well. The crawler stage is when they are most vulnerable so be sure to target early season.

    Biological Control

    Beneficial insects play a critical role in long -term suppression

    ·      Parasitic wasps

    ·      Mealybug destroyer

    It’s important to avoid broad spectrum sprays that kill beneficials, so be sure to consult your pest control adviser for the best in-season treatments.

    Ant Control

    Ant control is critical in managing growing vine mealybug infestations as ants will protect them in exchange for their honeydew. Without controlling ants, your biological control strategy becomes less effective, and infestations can spread more quickly. To control ants, you can:

    ·      Setup bait stations

    ·      Apply sticky trunk barriers

    ·      Apply targeted insecticides

    Monitoring and Timing

    Monitoring populations is essential as it allows you to time sprays effectively and reduce unnecessary applications thus improving ROI on inputs. Understanding the movements and stages of the infestation is essential for effective control. Growers often use a combination of pheromone traps and visual scouting under the bark to detect and track vine-mealybugs.

    Key Takeaways for Growers

    ·      Vine mealybug requires year-round management.

    ·      Timing of control methods is everything.

    ·      Combine chemical control, biological control, and ant management strategies.

    ·      Monitoring tools dramatically improve effectiveness.

    Vine mealybug is not a one-time fix; it’s a management system. Growers seeing the best results stay proactive, use integrated strategies and adjust based on monitoring data.

    Check out this video on control of Vine Mealybug HERE

    Check out our webcast on scouting for Vine Mealybug HERE

    —   By Hyrum Malcolm, Publisher

  • What Growers Need to Know about Sudden Grapevine Collapse

    Sudden Vine Collapse is a disease complex that has become a lot more widespread across California than was previously thought. First coined by growers as Mystery Vine Collapse, researchers now have some answers.  Watch this brief interview with UC Davis Plant Pathologist Akif Eskalen to find out more and read about it in American Vineyard Magazine.
     
    Please thank this video’s sponsor Suterra for their industry support.

  • California FSA Now Offers Assistance from Losses due to Grapevine Leafroll Disease

    The USDA California Farm Service Agency State Committee has approved Grapevine Leafroll Disease (GLD) under the Tree Assistance Program (TAP). Vineyard producers who incurred vineyard losses due to GLD will be able to sign-up under the Tree Assistance Program.

    Producers may sign up for Grapevine Leafroll Disease (GLD) at any time in their local county office. The deadline to apply for losses is 90 days after the loss became apparent to the producer. Producers applying for losses due to GLD must adhere to all TAP eligibility requirements.

    TAP was authorized by the Agricultural Act of 2014 as a permanent disaster program. TAP provides cost share financial assistance to qualifying orchardists and nursery tree growers to replant or rehabilitate eligible trees, bushes and vines damaged by natural disasters or plant disease which now includes Grapevine Leafroll Disease (GLD).

    Important: TAP requires preliminary inspections, including environmental compliance, prior to ground disturbance. Producers interested in the TAP program are advised to not conduct any ground disturbance (including, but not limited to, removal of vines, trellis and stakes) prior to obtaining permission from the FSA County Executive Director (CED) where the ground is located. Disturbing the ground prior to release by the CED will result in ineligibility for program benefits.

    To qualify for TAP:

    • The orchardists must suffer a qualifying tree loss in excess of 15 percent mortality from GLD, plus an adjustment for normal mortality (3%).
    • The eligible vineyards must have been owned when the GLD occurred; however, eligible growers are not required to own the land on which the eligible vineyards were planted.
    • The owner must provide evidence that trees existed and were lost due to GLD.
    • Receipts must be provided for actual expenses associated with removal, purchase and planting of vineyards.
    • An individual or entity’s average Adjusted Gross Income (AGI) cannot exceed $900,000
    • Other program and payment eligibility may apply

     

    If the TAP application is approved, the eligible vineyards must be replaced within 12 months from the date the application is approved.

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