What’s the connection between Washington’s fruit crops and tree-of-heaven?

An invasive insect harming grape vines and other crops in the northeastern United States might show up in Washington soon and scientists are using another invasive species to help them detect it early. Tree-of-heaven (Ailanthus altissima), an invasive tree species found in Washington, is a preferred host plant for spotted lanternfly (Lycorma delicatula), a potentially devastating insect pest known to attack apples, cherries, grapes, hops and many other plants. Although the insect hasn’t been found in the state yet, Washington State Department of Agriculture (WSDA) is asking for information on where tree-of-heaven is growing so they can monitor for it, hopefully before it finds its way to our crops and native plants. For many excellent images of spotted lanternfly and tree-of-heaven, see the University of Georgia Forestry Images website.

Here is the full scoop on why WSDA is worried about spotted lanternfly from Dr. Chris Looney:

Let’s get ready for Spotted Lanternfly, by Dr. Chris Looney, WSDA

Spotted lanternfly (Lycorma delicatula) is a species of piercing-sucking insect native to Asia. Adults and nymphs feed on sap from leaves and stems. The insects are strikingly colored and fairly easy to identify. The species became established in Pennsylvania by 2014, and quickly spread throughout the state. It has since been detected in Delaware, New Jersey, New York, and Virginia.

Spotted lanternflies have reached vast population levels in parts of Pennsylvania, and they feed on a wide variety of plants. Apples, cherries, grapes, and hops are just a few of the important species in Washington that they are known to attack. High infestations in Pennsylvania have resulted in the death of well-established grape vines. They also generate enormous amounts of honeydew excretions, which can cover plants, promotes the growth of molds, and attracts other insects.

While the adults can disperse by flying, transportation by humans is likely their fastest way of invading new areas. Adults prefer to feed and lay eggs upon the tree of heaven (Ailanthus altissima), a class C noxious weed in Washington State. Because of this, we are seeking to better understand the distribution of Ailanthus in the state, to consider whether removal of the species along critical pathways is feasible, and if some trees can be monitored to help detect the insect quickly once it arrives in Washington State.

Please add Ailanthus to your monitoring activities, and record precise locations when you see them. We already know the plant is widespread, but better data will help us evaluate our options for responding to this insect’s inevitable arrival in our state.

Further Information:

For more information or to report spotted lanternfly contact Dr. Chris Looney, WSDA, and for more information about tree-of-heaven or to report locations, contact your local Noxious Weed Control Board or Greg Haubrich with WSDA ghaubrich@agr.wa.gov. You can also report locations online at EDDMapsWest.org https://www.eddmaps.org/west/ or, in King County, you can use our Report-a-Weed online form.