Advisory Board: Integrated Pest Management Advisory Committee
Subject: : 4. RECEIVE a presentation on Ailanthus altissima (tree-of-heaven) and ADVISE staff, as appropriate
Presenter: Bill Neill
Contact: Wade Finlinson, 925.655.3214
Information:
The bylaws of the Integrated Pest Management Advisory Committee (IPMAC) list several purposes of the Committee. Those include:
• Making policy recommendations upon assessment of current pest issues and evaluation of possible IPM solutions.
• Providing a forum for communication and information exchange among members in an effort to identify, encourage, and stimulate the use of best or promising pest management practices.
Referral History and Update:
On November 20, 2025, IPMAC received presentations on the County’s development of an Urban Forest Management Plan (UFMP) and revisions to the Tree Preservation Ordinance. During these and previous discussions, Committee members have raised concerns about Ailanthus altissima or tree-of-heaven (ToH).
ToH is a widespread noxious weed that is considered a significant urban and agricultural pest. In urban conditions, aggressively spreading root systems can damage infrastructure within the built environment. It also crowds out native species and attracts nuisance insects that excrete honeydew and creates a substrate for sooty mold. In Agricultural settings, ToH is the preferred host for the spotted lanternfly (Lycorma delicatula) (SLF). If SLF arrives in California, it will pose a significant threat to grapes and other important crops.
Bill Neill has worked to combat ToH and variety of other invasive species for several years in Southern California. In consultation with the IPMAC Chair, Mr. Neill has been invited to present at this meeting. A copy of slides he presented on the topic at a California Invasive Plant Council (Cal-IPC) symposium are attached. An LA Times video documenting his recent work in the areas that burned last January is available at the following link: <https://www.latimes.com/0000019a-2d56-d87b-a7fe-ff5770300000-123>
Additional information is available from the University of California Agriculture and Natural Resources, Cal-IPC, and Calflora.org. Also, review presentations from the Sonoma County Agriculture Commissioner and Sonoma Resource Conservation on ToH that comprise the first forty minutes of the 2024 Statewide Weed Management Areas (WMA) Meeting at this link:
<https://www.youtube.com/watch?v=QsmqGwoIOUM&t=1512s>
Recommendation(s)/Next Step(s):
Staff recommends receiving the presentation and advising on potential next steps.