The Spotted Lanternfly Threatens Forests and Agriculture

The spotted lanternfly (lycorma delicatula)  is an invasive insect first discovered in Pennsylvania in 2014.   The adults are one and a half inches long.   The abdomen is yellow with black bars, the forewing is gray and speckled black, and the hind wing is bright red with a white stripe in the middle and the black tip.   The nymphs are black with white spots.  They are confirmed in Pennsylvania, New Jersey, Virginia, and Delaware.  They have been detected in Connecticut, Maryland, and New York, though an entire population has not been confirmed in these states   It is believed that egg masses arrived in the U.S. via a shipment and were not detected.

They are native to China, India, and southern Asia.   They feed on sap, which depletes the nutrients in trees, especially in high density.   They attack a large number of species,    which includes apples, plums, cherries, peaches, nectarines, apricots, almonds, grapes, maples, oaks, pines, walnuts, poplars, willows, sycamores, and the tree of heaven.  According to Heather Leach, the Extension Associate for the Department of Entomology for Pennsylvania State University, few trees have died as a result of infestation, but some such as the black walnut, red maple, and silver maple have shown signs of stress.  Leach said it was too soon to tell what effect the stress was having on trees, but she “expected” they would have a harder time recovering, especially in unfavorable weather conditions.   She also said some trees were “oozing”  and researchers were “paying close attention to trees showing stress.”  As to whether certain species were more susceptible than others, Leach said not much is known about the lanternfly’s preferences and that they appear to be dependent on what is available.   She also said, however, that there was some evidence that they were attracted to black walnut, river birch, grapes, hops, silver maple, red maple, sycamore, and willow.

The symptoms of infestation include weeping wounds, grayish or black trails of sap, and egg masses that have a gray covering that can appear dry and cracked.  In the fall adults congregate on tree trunks and lay eggs in late September on trunks, branches, stones, and other smooth surfaces.  The egg masses generally contain 30-50 eggs that are an inch long.   They are gray and covered in a waxy material that dries and cracks.  The nymphs hatch in the spring and mature in the summer.

Management options include removing host trees, creating traps by spraying trees with insecticide, putting sticky bands on trees, and scraping off egg masses.  Leach said that insecticide has been the most effective management tool to date, though sticky bands and removing egg masses may help to reduce populations locally.  She also said that not much is known about what preys on the spotted lanternfly in its native range, but researchers have found several parasitic wasps  that were promising biological control and are currently in a quarantine facility for potential release in the U. S.  She stated that the best way to prevent the spread was to report it, so they could be killed when found in new areas.

With the almost constant movement of people and goods, it is nearly inevitable that there will be unwanted passengers and sometimes these passengers can do enormous harm.   The spotted lanternfly is no exception.  Nevertheless, reporting signs of infestation and following quarantines can go a long way to reducing the effects on farms, forests, and ecosystems.


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