Spotted Lanternfly & Ailanthus Project

Ecological Concern

Two Invaders, One Complex Alliance

Spotted Lanternfly and Tree-of-Heaven are interlinked species, managing one requires understanding both. SLF strongly prefers Ailanthus as a host, creating concentrated zones of infestation wherever the tree is present, while also feeding on many native trees. Controlling Ailanthus is therefore a key strategy for reducing SLF populations across the Hudson Valley.

Spotted Lanternfly (SLF)

Lycorma delicatula

Origins & Spread: Planthopper native to Asia, first detected in the US in 2014. Reached the Hudson Valley by November 2020 and was officially confirmed on Mohonk Preserve in late 2023. Spreads primarily by hitchhiking on vehicles and clothing.

Agricultural Impact: A severe plant stressor whose heavy feeding impacts important economic crops including hops, grapes, and apples as well as native trees like black walnut and red maple.

Property Impact: High populations excrete sticky "honeydew" that coats surfaces and attracts stinging insects, creating significant nuisance and aesthetic issues for homeowners.

Tree-of-Heaven

Ailanthus altissima

Origins: This tree, which is native to China, was introduced to the United States in the 1700s as an ornamental plant. Once valued for its resilience, it now actively out-competes native flora across the region.

Aggressive Survival: Reproduces rapidly via seeds and clonal root shoots. Uses allelopathy secreting toxic chemicals from its roots to actively suppress neighboring native vegetation.

Removal Danger: Cutting Ailanthus triggers a survival response where the root system can send up to 300 new clonal sprouts. Felling just 2 trees can yield 600 new sprouts.

Conservation Efforts

Mohonk Preserve's Operational Year

Our Conservation Science team and trained volunteers follow a precise seasonal workflow tracking, trapping, treating, and documenting at every stage of the SLF lifecycle.

Phase 1

Winter / Spring

November – May

Surveys at trailheads and high-traffic zones for egg masses, prioritizing known Ailanthus stands.

Egg masses counted, documented, and scraped to prevent hatching.

Three trap types deployed mid-April ahead of nymph emergence: circle traps (wrap tree trunks), sticky traps (adhesive capture), and lampshade traps (intercept egg-laying).

Phase 2

Spring / Summer

April – August

Surveys at trailheads and high-traffic zones for nymphs and adults, prioritizing known Ailanthus stands.

Weekly trap monitoring all captured specimens documented and destroyed.

Concurrent trailhead monitoring for new Ailanthus growth from April through July.

Year-round interior forest health surveys to check for new SLF infestation and Ailanthus growth.

Phase 3

Late Summer / Fall

July – December

Targeted herbicide application via foliar, basal bark, or hack-and-squirt methods.

Treatment targets tree infrastructure with reduced native plant byproduct risk when applied correctly.

Mechanical extraction of above-ground Ailanthus should only occur after tree death is confirmed.

Why Ailanthus Management Is Important to Successful SLF Management: Ailanthus is the highly preferred host tree for Spotted Lanternfly, and reducing its abundance directly limits the habitat and food sources that sustain SLF populations. This is why Mohonk Preserve's Ailanthus removal efforts are central to our SLF management approach treating both species together is more effective than addressing SLF in isolation.

Scientific Monitoring

Data Insights & Field Findings

Our field data informs adaptive management. The following visual analyses are shared for scientific transparency and community engagement. Full interactive maps are available via Mohonk Preserve's GIS portal.

Bar Chart

Trap Detection Rate by Site

Table Rocks Trail, Kleine Kill Farm, and Cedar Drive identified as high-likelihood SLF detection zones based on trap data.

Timeline Scatter

First Adult Detection Date by Site

Comparing adult SLF emergence shifts between 2024 and 2025 across key hubs including the Visitor Center and Brook Farm.

Heat Map

Adult SLF Sum by Location

Geospatial heat map of adult SLF abundance using exact latitude/longitude clusters recorded across the Preserve.

GIS Map

SLF Detection Locations & MP Boundary

Regional GIS map showing localized infestation points overlaid on official Mohonk Preserve parcel boundaries.

GIS map of SLF detection locations and Mohonk Preserve boundary

Research Presentation

NYS Invasive Species Expo September 2025

Invasive Species Technician Melissa Torchio presented findings at the 2025 NYS Invasive Species Expo: "Tracking Changes in Abundance and Spread of Spotted Lanternfly." Images, slides, and supplementary data available upon request.

Presenter standing with SLF research poster

SLF research poster presented at the NYS Invasive Species Expo

Take Action at Home

Homeowner Management Guide

Property owners play a critical role. Here's what you can do right now and what you should avoid to prevent spreading these invasives.

Spotted Lanternfly Control

Circle Traps: Best for tree trunks over 15 inches. Source via Great Lakes IPM or build your own using PennState Extension's free guide.

Lampshade Traps: Constructed to intercept egg-laying. UMass Amherst provides detailed build guides. Especially effective in high-density SLF zones.

Egg Mass Removal: Scrape and destroy egg masses between late fall and spring. Each mass harbors 30–50 eggs. Scrape into a jar of rubbing alcohol to kill on contact.

Report Sightings: Log all SLF observations on iNaturalist or iMapInvasives while on the trails or on your property.

Recommended apps:

iNaturalist iMapInvasives Penn State Extension Great Lakes IPM

Ailanthus (Tree-of-Heaven) Control

Best Management Practices

DO NOT simply fell Ailanthus trees. Cutting triggers a survival response where the root system generates up to 300 new clonal sprouts per tree. Felling just 2 trees can produce 600 new sprouts, dramatically worsening the infestation.

Integrated Vegetation Management (IVM): The only effective long-term strategy targets tree mortality, not just above-ground growth.

Herbicide Application: For stems under 6 inches, apply systemic herbicide (triclopyr or glyphosate) directly to the lower bark (basal bark method) no cutting required. For stems over 6 inches, use the hack-and-squirt method: make cuts in the bark and apply herbicide directly into the living tissue for maximum tree uptake. Note: some herbicide applications require a licensed professional.

Mechanical Removal: Above-ground growth can be extracted anytime after tree death is confirmed.

Safety First

Always wear full Personal Protective Equipment (PPE) because Ailanthus sap can cause skin irritation. Consider hiring a licensed professional removal service for large specimens.

Get Involved

Join the Forest Guardians

Work directly alongside our Conservation Science team performing species and habitat surveys, mapping invasive distribution, and assisting in hands-on removal efforts. Your time makes a measurable difference in protecting Mohonk's native ecosystems.

Email Community Science Apply Online to Volunteer

Must be 18+ to apply online. Paper copies available at the Visitor Center. | research@mohonkpreserve.org

Spot Something on the Trails? Report SLF or Ailanthus sightings directly from your phone no account required for basic reports.

iNaturalist iMapInvasives

Every data point strengthens our detection map and shapes future management decisions.