Worry? That depends.
First, spotted lanternflies do not bite or sting.
They feed exclusively on plants outdoors and can only survive for about 48 hours without feeding on a plant. In natural and residential areas, they feed on Tree of heaven (Ailanthus), black walnut, maples (they will preferentially feed on silver maple, then red maple), willow, river birch, black cherry, tulip poplar, and other trees. Like agricultural crops (with the exception of grapes), they do not appear to be damaging trees. They can, however, be a nuisance because of their sheer numbers.
Because spotted lanternfly, a phloem feeder, consumes large quantities of a plant’s sugary sap to extract nitrogen and amino acids, it expels large quantities of excess sugar-water (honeydew). Honeydew—often misidentified as sap—shows up on outdoor equipment, decking, and vehicles as well as pets and your clothing and hair. Left to accumulate outdoors, honeydew acts as a growth medium for thin, dark layers of sooty mold fungi. Bees and wasps are also attracted to the sweetness, so there can be an increased stinging risk around infested plants.
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Spotted lanternfly has proven to be a serious pest of grapes (both cultivated and wild). They are swarm feeders and up to 400 SLF adults per vine have been reported. Feeding by a population this high has been shown to weaken the vine, leading to loss of winter hardiness, reduced or no return bloom or crop, and even vine death. They don’t seem to be causing significant damage to agricultural crops like hops, apples, or peaches, but the issue is still being studied.
Spotted lanternfly will be a nuisance pest for some and a big concern for others such as vineyard owners. The extent of their spread and their subsequent establishment and feeding damage is yet to be determined. NY State’s Agriculture and Markets, the NYSIPM Program, and many others have been actively watching and planning. Tactics have been discussed but the public’s help will always be needed.
Why are they here? Why MY YARD?
Spotted lanternflies are common hitchhikers at all life stages, but adults and egg masses are most commonly moved.
Adults will fly into open windows of vehicles, into picking bins, and into the back of trucks while they are being loaded; eggs can be found on almost any outdoor surface. Transportation by human activity is the most common form of movement and the main reason SLF populations have spread significant distances.
Moving an outdoor item that unknowingly has an egg mass to a new location is a common way spotted lanternflies spread to a new location. Common items on which egg masses have been laid include firewood, motor homes, recreational vehicles, building materials, and even kiddie pools. To reduce the risk of these hitchhiking pests, the NYSIPM Program has created a SLF Checklist to use when visiting an area with known populations of SLF.
This series of blog posts reflect our spotted lanternfly resources in September of 2021. All content here is adapted.
OUR FULL RESOURCES ON SPOTTED LANTERNFLY ARE AVAILABLE ON OUR WEBSITE AT: https://nysipm.cornell.edu/environment/invasive-species-exotic-pests/spotted-lanternfly/