State agriculture departments across the country are urging people to show no mercy if they encounter a spotted lanternfly. The invasive species sucks the life from trees and crops while leaving behind a nasty residue that encourages the growth of sooty mold. Native to China, India, and Vietnam, the spotted lanternfly was first detected in Pennsylvania in 2014 and has since spread to multiple counties in that state and at least six other eastern states. The pest is now moving into southern New England, Ohio, and Indiana, and experts fear it’s only a matter of time before it spreads to most parts of the country.
The spotted lanternfly is easy to kill, susceptible to most pesticides as well as heat, frost, and good old-fashioned squishing. However, the species also reproduce quickly. Spotted lanternflies lay egg masses – 30 to 50 eggs at a time – in late summer and autumn on the trunks of trees and virtually any smooth-surfaced item sitting outdoors. The egg masses, which resemble smears of dry mud, can also be laid on the surfaces of cars, trucks, and trains. Then, they can be unintentionally transported to any part of the country in just a few days. Once the eggs hatch, the nymphs crawl to nearby host plants to start a new infestation.
With few natural predators in the U.S., spotted lanternfly populations can easily build to huge numbers in a short period of time. According to Frank Hale, a Professor of Horticultural Crop Entomology at the University of Tennessee spotted lanternflies were introduced into South Korea in 2004 and spread throughout that entire country – which is approximately the size of Pennsylvania – in only three years.
While the tree of heaven is the pest’s preferred host, the insect is of agricultural concern as its host range covers some 70 different species of plants. It is also fond of grape and fruit trees, hops, blueberry, oak, pine, poplar, and walnut. Adult spotted lanternflies mainly feed on grapevines and tree of heaven, while nymphs feed on a wide range of hosts.
Both adults and nymphs feed on stems and leaves. They feed by piercing the bark of trees and vines to tap into the plant’s vascular system to feast on sap. The feeding seriously stresses trees and vines, which lose carbohydrates and other nutrients meant for storage in the roots and eventually for new growth. Infested trees and vines grow more slowly, exhibit dieback, and can even die. The damage that the lanternfly feeding inflicts also leaves plants more susceptible to other insects and diseases. Spotted lanternflies also excrete copious amounts of clear, sticky “honeydew” that can coat trees, plants, and anything beneath. A black sooty mold grows wherever the honeydew has been deposited and, while it isn’t harmful, it can quickly become a blight on the landscape. The honeydew also attracts other insects.
Several state ag departments have placed counties under quarantine in an effort to curb the spotted lanternfly’s spread. Many have also come up with aggressive campaigns to raise awareness and hopefully encourage more residents to join the fight. According to the Ohio Department of Agriculture (ODA), now through November is the best time to identify the SLF because it is in its most recognizable stages as a nymph and a moth. After hatching in the late spring, the SLF goes through four nymph stages. By midsummer, the nymph SLF can be identified by its red body, roughly a half-inch in size, with black stripes and white dots. During the late summer until roughly November, the SLF is in the adult moth stage. These adults are larger, roughly one inch in size, with black bodies and brightly colored wings.
Experts say the most effective way to stop the spread of spotted lanternflies is to remove their favorite food source, the tree of heaven, which is itself an invasive plant species from China. Destruction of eggs can help reduce the number of Spotted Lanternflies. Scraping the egg masses off trees and destroying them manually or with the chemical chlorpyrifos can reduce their numbers, but experts warn it is not likely to stop an infestation completely. If you think you’ve seen spotted lanternfly in your area, contact your state Department of Agriculture to find out the best course of action. PennState Extension has a good general information page on spotted lanternfly with links to other resources HERE. (Sources: ODA, PSU, The New York Times)