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Control 2025
SLF Now
SLF stands for Spotted Lantern Fly, and it is now well established in Rockbridge C o u n t y . There is a good chance Rockbridge will experience a significant rise in its Spotted Lantern Fly population in 2025 and now is the time to take action to limit the impacts around your property.
The Ailanthus tree, widely known in Rockbridge as the “Paradise Tree” or “Tree of Heaven” is the preferred feeding and egg-laying destination for SLF. While SLF will feed on and lay eggs on a wide range of tree species, their favorite is the Ailanthus and destroying all the Ailanthus trees we can is the best strategy we have at this point to limit the impacts of SLF. We cannot eliminate Spotted Lanternfly, but destroying Paradise trees will curb SLF impacts and presence.
Fortunately, control strategies for Ailanthus this time of year can be adapted to help treat a rogue’s gallery of weeds that plague Rockbridge because they are highly susceptible to herbicide treatment in the fall.
September through October is an ideal time to kill certain perennial trees and herbaceous plants because, in response to shortening day length and cooler nights, these are retarding their growth rate and translocating more nutrients from the leaves into the root system. This creates an opportunity to maximize the extent to which our herbicide treatments penetrate into the root systems of these perennials.
Many landowners object to the use of any herbicides. Eliminating Ailanthus, Autumn Olive, and other woody perennials solely by physical removal demands multiple cut-and-remove efforts each year and new seedlings will constantly be reestablished. “Home remedies” such as vinegar, garlic, or petroleum products are not effective.
The most common herbicides employed in control are triclopyr (Remedy or Garlon), 2,4-D and Dicamba (sold under a number of different names) and aminopyralid (Grazon Next). Glyphosate (Round-Up) can be effective but is not ideal because this is a broader spectrum herbicide that is more likely to impact grasses and non-target plants. Effective herbicide options that minimize the amount of chemical released to the environment include painting the bark with a 33% herbicide, 66% oil mix. The oil carrier can be diesel fuel, kerosene, or a more environmentally benign crop oil.
Many folks cut the Ailanthus and immediately treat the cut stump. A number of agronomists have advised your columnist that while a cut stump treatment can be effective, a basal bark spray or paint brush application the full circumference of the tree from very close to ground level to 12 or 18-inches above ground and then delaying cutting for a few weeks better assures full uptake of the herbicide by the tree. Areas where Ailanthus trees have been cut and/ or sprayed previously often have significant resprouting of seedlings that are now 1 to 5 high. These can be effectively and more efficiently treated by spraying the leaf area with a broadleaf herbicide mixed with water and surfactant.
Basal bark treatment of large specimens and spray treatment of shorter leafier seedlings also is very effective this time of year on Autumn Olive, Sumac, Poison Hemlock, and thistle species. For the later two on this list, the tall dry stalks from this year are not the target, rather the fine diffuse leafy rosettes found at the base of these stalks are the target.
For resources to assist you in developing a weed control strategy, contact the Rockbridge Extension Office at (540) 463-4734 or by e-mail to [email protected].
