HWA: Treatment Options

Hemlock Woolly Adelgid Management Strategies

Hemlock woolly adelgid (HWA) is a tiny exotic invasive pest plaguing hemlocks in the Eastern U.S., killing 90% of hemlock trees in Shenandoah National Park, VA, as well as vast stands of hemlocks in North Carolina, Eastern Tennessee and Northern Georgia. Research has demonstrated that Safari® Insecticide can protect hemlock trees from HWA.

Due to its unique chemical properties (high solubility and low binding to organic matter), high amounts of Safari are rapidly absorbed by hemlock trees and then transported in the vascular system to where HWA feeds. This results in faster control of HWA than with less systemic products and also extends the application window later in the season.

HWA does not have to be a death sentence for hemlock trees. Systemic insecticides are effective at protecting hemlock trees from HWA infestation and can also be used to save trees already showing early signs of infestation.

  1. Tree removal

    • Will not stop HWA spread
  2. Insecticide treatment

    • High rate of success
    • Preventive or early curative application key
  3. Biological control with Pt beetles

    • Difficult and expensive to rear
    • So many hemlocks, so few beetles
    • Not recommended for a home or nursery setting
  4. Combination of 1 and 2

    • Treat signature/high-profile trees
    • Remove stressed or less desirable trees
  5. Product Choice Considerations

    • Efficacy is NOT the only consideration
    • Also consider:
      • Speed of application (labor)
      • Ease of application (applicator training)
      • Flexibility of application (use methods)
      • Customer budget (cost)
      • Level of tree injury (preventive vs. curative)
      • Time of application (season)

Safari Advantages

Because Safari is highly systemic, it penetrates the bark into the xylem when applied to the trunk and is then quickly transported upwards to where pests feed.

Safari delivers:

  • Super-systemic activity means rapid uptake and control following soil application
  • Broad spectrum control
  • Unsurpassed residual performance
  • Favorable environmental profile

Safari Controls Hemlock Woolly Adelgid in Landscape

Find a Tree Care Specialist to Treat Your Trees


Safari Insecticide is also available for homeowners who prefer a do-it-yourself approach to tree and shrub care. Tree & Shrub Insect Control with Safari 2 G Insecticide is available at local lawn and garden stores across the country. Visit www.greenlightco.com to purchase Tree & Shrub online or locate the retailer nearest you.