The Spotted Lanternfly Comes to Ohio!

​

Spotted lanternfly (SLF) is an invasive insect that has spread in other states including New Jersey, New York, Connecticut, Maryland, Delaware, Virginia, and West Virginia and most recently Ohio, including Franklin County!  SLF feeds on the sap of many different plants including grapevines, maples, black walnut, and other important plants , while also attacking Tree of Heaven (ailanthus).   SLF is a plant stressor that, in combination with other stressors (e.g., other insects, diseases, weather), can cause significant damage to its host. SLF alone may not kill the tree.

SLF cannot bite or sting. They feed on plant sap through a tiny, straw-like mouth part.  As SLF feeds, the insect excretes honeydew (a sugary substance) which can attract bees, wasps, and other insects. The honeydew also builds up and promotes the growth for sooty mold (fungi), which can cover the plant, forest understories, patio furniture, cars, and anything else found below SLF feeding.

The Ohio Department of Agriculture asks to please report any suspected SPL infestation at any life stage by taking a picture or collecting a sample and report the finding to the ODA Plant Pest Control using the Ohio Plant Pest Reporter.

Life stages of spotted lanternfly

SLF Life-Cycle

The eggs are laid in the fall (September to November) and hatch in the spring (late April to June). Egg masses are laid on the surfaces of trees, decks, houses, outdoor equipment, rocks, etc., and are protected with a mud-like covering. Each egg mass contains an average of about 35 individual eggs. After hatching and before reaching adulthood, SLF goes through four nymphal stages (wingless) as shown in the diagram below. Newly hatched nymphs are small (~⅛ inch) and can be hard to find, and may be mistaken for small ticks or spiders. With each molt to the next stage, the nymphs roughly double in size, and are black with white spots. The last (fourth) stage is red with white dots and black stripes and roughly ½ inch long. SLF nymphs and adults are strong jumpers.  SLF adults begin to emerge in summer and remain active as adults until they are killed by hard freezes later in the fall. Adults are the most obvious and easily detectable stage because they are large (about 1 inch) and highly mobile. Adults have black abdomens with yellow bands that become visible as they mature. Their forewings are gray with black spots, and the tips are black with gray veins, while their hind wings are red, black, and white. Only the adults have wings and can fly. However, because SLF adults walk more than fly, their wings often remain closed, leaving only the forewings visible. This makes them more difficult to identify in low numbers, from a distance, or when they are high in a tree.

Spotted lanternfly life cycle. Illustration © Emily S. Damstra.

Feeding Damage

SLF feed on plant sap using piercing-sucking mouthparts. They acquire nutrients from the plant sap and also rely on associated bacteria in their guts to support their nutritional requirements. The sap they ingest contains high amounts of sugar, which is not completely digested by the insect. They excrete the excess as a liquid waste substance called honeydew, which can build up below the feeding insects. On sunny days, honeydew can be seen falling from trees, resembling a light rain. Honeydew is attractive to ants, wasps, bees, and other sugar-loving insects. As the honeydew accumulates, it is often colonized by sooty mold (fungi). Sooty mold does not directly harm plants or the surfaces on which it grows, but it does physically cover leaves, reducing photosynthesis. With dense groupings of SLF, understory plants may die because of the sooty mold buildup on their leaves. Sooty mold frequently stains objects such as tree trunks, decks, patios, and vehicles that are underneath affected trees. These stains can be very difficult to remove.

Consequences of direct feeding damage by nymphs and adults to the host trees vary greatly by host species, numbers of SLF feeding, and environmental conditions. While SLF feeding can stress plants and cause localized branch damage, it is not known to kill plants except for grapevines, Tree of Heaven, and black walnut saplings.

SLF, especially the nymphal stage, will feed on vegetable, fruit, and herb plants. However, damage is seldom reported and only seen when plants are subject to very high SLF populations. Watch for SLF feeding on cucumber, basil, horseradish, raspberries, asparagus, and other herbaceous plants.

SLF thrives on Tree of Heaven, an important invasive tree degrading many areas in Ohio.  Its important to identify and control it to also potentially reduce SLF populations.  While Tree of Heaven is a preferred food source, SLF does not require it to complete its lifecycle

Management

It is important to understand that SLF cannot be prevented from coming onto any one property. SLF is a complex pest problem, and unfortunately, there is no “one size fits all” solution. Each situation is different and deciding on a plan of action requires everyone to assess their situation and decide what makes sense for them. Properties can experience sudden increases in populations of nymphs, but this occurs more commonly with adults. SLF adults tend to fly to new trees to feed in the late summer. Additionally, the presence of low numbers of SLF may not necessitate treatment.

There are many things to consider before deciding to use an insecticide to kill SLF on landscape trees or shrubs. SLF nymphs and adults are both fairly easy to kill with insecticides; even the less-toxic, registered insecticides like soaps and oils can work well. Some things you should take into account are (1) the number of SLF present, (2) whether they are on a preferred host plant, where they are likely to remain, or on a plant they will move away from after a shorter visit, (3) the size and health of the plant, (4) the presence or absence of preferred host plants in the landscape, and (5) the life stage of SLF present.

Currently, there are no known natural enemies of SLF that are expected to significantly reduce SLF populations in the United States. Some generalist predators (spiders, praying mantises, parasitoids, birds, etc.) will attack and eat SLF.

SLF eggs can be destroyed by scraping them from the surface where they were laid into an alcohol solution (e.g., rubbing alcohol or hand sanitizer) where they should be left permanently.  Eggs can also be destroyed by thoroughly smashing them.

Female SLF will lay their eggs in a variety of places and on a wide range of surfaces. One common place to find eggs is on or near trees where females were feeding during the egg-laying period in the fall. Tree hosts preferred by SLF during the fall include red maple, silver maple, and willows—these trees are an excellent place to start looking for egg masses. SLF will also lay eggs on other trees on which they do not typically feed. They will lay eggs in protected areas under rocks and on lawn furniture, decks, fences, rusty metal, and many other surfaces.

Each destroyed egg mass can remove about 35 SLF from the next year’s generation, but you are unlikely to destroy all SLF in an area. Continued management strategies may be necessary the following year.

Acknowledgments

This article was largely based on information from the Penn State University Extension Services, and is current as of June 2023.  We appreciate their permission to share their excellent materials.  Additional information is available at the Penn State  Spotted Lanternfly Management Guide (psu.edu). They recommend checking the online version of this management guide and always look for the most up-to-date information. When using any pesticide, follow the pesticide label for directions, application rates, methods, and appropriate protective equipment. Remember, the label is the law.