Spotted Lanternfly: A New Pest in Arboriculture
The spotted lanternfly, Lycorma delicatula, is an invasive plant hopper native to China, Vietnam, and India. The spotted lanternfly was confirmed in Pennsylvania in September 2014. Adults can lay eggs on any smooth surface like rocks, siding, or bricks which make them extremely easy to spread. If left unchecked, this pest can result in the major decline of many ornamental trees.
While the tree of heaven (ailanthus) is the most common host tree, adult insects are known to feed on around 70+ species of plants including trees, shrubs, and agricultural crops.
How Does it Harm Trees?
Adults and nymphs feed by sucking sap from the leaves and stems of their host plants, causing the wounds to ooze and leaving a foul odor. Weakened plants are open to attack from other pests and diseases, which can further stress or kill the plant. On tree of heaven, its preferred host, trees typically die within 2-4 years after initial attack.
A Nuisance to People
Along with the physical damage these insects cause, they secrete a sticky substance (called ‘honeydew’), which spreads over anything underneath the attacked tree. Surfaces covered by the honeydew will subsequently be covered in a black sooty mold, resulting in a dirty appearance to patio furniture and other infrastructure as the mold grows.
Reduce the Spread
If you spot egg masses or the insect itself the best option is to contact your local Extension agency or your State Plant Regulatory Official. These egg masses can be found on the bark of host plants or any smooth surface such as cars, trailers, siding, brick, stone, and so on. Make sure to inspect vehicles before taking trips. Adults are easiest to spot at dusk when they congregate on host plants moving up and down the trunk.
A Special Local Need label has been approved in Pennsylvania for Transtect 70 WSP to treat Tree of Heaven as a basal trunk spray. Trees should be treated between mid-late May and August. Transtect can be used as an annual treatment to protect high value trees.
Transtect is a soil applied, systemic insecticide that provides season long control of a broad spectrum of pests. Its unique properties provide rapid uptake and efficacy. Transtect can be used for a variety of situations where fast results are needed including recovery treatments on infested trees.
Brandon Gallagher Watson is an ISA Certified Arborist and the Creative Director of Rainbow Tree Company. Rainbow consists of a full-service tree care company, a lawn care and pest control division, and Rainbow Treecare Scientific Advancements, a research & development branch dedicated to developing tools and protocols for science-based tree care.