What is the most effective treatment for Spotted Lanternflies?
First I’d like to address the idea of why removing Tree of Heaven hasn’t been effective in eradicating Spotted Lanternflies. While the Tree of Heaven is their preferred host, the Lanternflies have adapted here in the US and will gladly infest Maples, Willows, and many other trees and vines as well as vegetables and fruits. There are over 70 known host species they will feed on. Tree of Heaven has been named an invasive species so there might be other good reasons for removing them. However, removing otherwise healthy non-invasive deciduous trees is definitely not the answer as we need more trees to help the environment, not less. If you have a Tree of Heaven in your yard, you might actually want to consider keeping it for now and using it as a bait tree to keep the Lanternflies away from your other trees. The Tree of Heaven could be treated by a pest control company that is licensed to treat trees in order to help reduce the number of Lanternflies in your yard.
Spotted Lanternflies have 3 stages: egg stage, nymph stage, and adult stage. While it appears there is no way to completely eradicate these pests at this time, we can take steps to greatly reduce their numbers.
The Spotted Lanternflies lay their eggs in the fall. The eggs are protected by a substance that gives egg masses a cracked whitish to gray appearance. The mass protects the eggs during the winter months. Each mass can hold 30-50 eggs. The egg masses are up in the trees, usually on the underside of branches but can be in congested areas of trees where they are difficult to spot. If you see them they can be scraped off and killed by placing in a bag with rubbing alcohol or something along those lines. However, since they can be high up in the tree, this won’t be effective in getting most of them. Same goes for home made spray remedies for the eggs. It would be impossible for most home owners to reach the tops of trees with sprays. Penn State researchers have found that the egg masses can be smothered by applying Horticultural Oil in a general spray all over the tree. We have a spray truck with a compressor that allows us to reach the tops of most trees and we can apply Hort Oil in an attempt to reduce the numbers. However, this will not eradicate the problem completely. Some eggs might survive the spray and once hatched the insects can come back from surrounding areas or neighboring yards.
The eggs begin hatching in the spring, usually in May, but can continue to hatch into June. Once the eggs hatch, the nymphs will eventually fall to the ground and begin crawling up the tree to feed on it. This is when we actually like duct tape bands to trap and kill many of them and reduce their numbers. It’s a good idea to apply two separate bands, sticky side out, around the trees and wrap them as tightly as possible. We recommend applying the first maybe a foot or so off the ground and the second band maybe another foot higher. We like duct tape better than the wide sticky tape bands sold in stores because those have such an extremely wide sticky surface that they end up catching and killing squirrels and birds. We definitely don’t need any further decrease in bird populations. If you are going to use those wide sticky bands, you will need to secure window screening around them to prevent this from happening. We haven’t seen anything other than insects caught when using a single band of duct tape with another maybe a foot up from it. The duct tape must be changed weekly since it won’t be as sticky after a rainfall. We haven’t seen any butterflies or bees killed with this method so far. This could be because we are placing the bands lower to the ground and we are not using them on shrubs which would attract butterflies. We are only using the duct tape bands on our deciduous trees.
Once the Lanternflies’ wings have sprouted they will be more difficult to control since they can easily make their way over from neighboring yards until they have infested entire neighborhoods. Lanternflies are leaf hoppers and don’t actually fly. They glide from tree to tree and can make it quite a distance before landing and taking off again. This enables them to easily travel from neighbor’s trees making them difficult to control. If you have a severe infestation, you might want to consider trying pesticides at that point to get them under control and again reduce their numbers. There are pest control companies who are licensed to spray trees also. We don’t use pesticides because we prefer to stick with organic products. However, there are several companies we know of in the area that can spray your trees for Lanternflies. It is usually expensive because the treatment recommended by Penn State research is a very expensive product to purchase. There are pesticides on the market now, which are labeled for use on Lanternflies by homeowners, however, we have not tested these so we can’t say whether or not they would be effective long-term. They would likely reduce the numbers but if you are considering these, please do a little research to make sure they won’t harm your trees or you.
It appears as though Spotted Lanternflies are going to be an ongoing problem. Recent research has shown that while the pests are a problem, they aren’t killing trees so far as was once feared. Homeowners should all take steps to reduce their numbers such as duct tape bands, which are changed weekly. If you notice you have a severe infestation and are seeing them in large numbers, you can call us here at Joyce Tree Service for Horticultural applications in early spring to kill the egg masses. Also, you can apply the duct tape for the ones the spray might miss or that hop over from neighboring yards. In the summer once the wings have sprouted, you can try one of the pesticide companies who are licensed to treat the trees if the infestation is severe enough to warrant extreme measures. Hopefully, if we all do our part to reduce their numbers, these pests will at least be under control until the scientists can find a way to eradicate them.