Tuesday, August 17, 2021

Keep an Eye Out for the Spotted Laternfly

This summer the Spotted Lanternfly (lycorma delicatula) is making its way through New Jersey unimpeded, it would seem. The images to the left were taken by yours truly in two different patches of woodland, and represent the insect in two of its phases of growth. The full set of four phases are illustrated at the bottom of this post. As for why these invasive pests pose a problem, here's what the New Jersey Department of Agriculture has to say: 

Spotted Lanternfly (SLF), Lycorma delicatula, is an invasive planthopper native to China, India, and Vietnam; it is also established in South Korea, Japan and the U.S. It was first discovered in the U.S. in Pennsylvania in Berks County in 2014 and has spread to other counties in PA, as well as the states of New Jersey, Delaware, Maryland, Virginia, West Virginia, New York, Connecticut and Ohio. 
This insect has the potential to greatly impact agricultural crops and hardwood trees. SLF feeds on the plant sap of many different plants including grapevines, maples, black walnut, and other important plants in NJ. While it does not harm humans or animals, it can reduce the quality of life for people living in heavily infested areas. 
Why You Should Care 
SLF is a serious invasive pest with a healthy appetite for our plants and it can be a significant nuisance, affecting the quality of life and enjoyment of the outdoors. The spotted lanternfly uses its piercing-sucking mouthpart to feed on sap from over 70 different plant species. It has a strong preference for economically important plants and the feeding damage significantly stresses the plants which can lead to decreased health and potentially death. 
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.

As bad as this seems, I'm hoping that the species already present in North America will prey on SLFs. According to an informal PennLive survey of gardening groups on Facebook last year, some creatures have been observed doing just that.

From hundreds of responses, the No. 1 and 2 reports were of praying mantises seen eating adult lanternflies and garden spiders at least snaring lanternflies in their webs and killing them, if not eating them. 
Others reported yellow jackets, gray catbirds, wheel bugs, hornets, fishing spiders, green frogs, dogs, cats, goldfish, koi and ducks eating the invasive insects. Some chicken owners reported that their birds ate lanternflies, while others said the chickens avoided the insects after one taste.

The simple truth is that there's no way to safely and completely exterminate this species now that it is present in North America. I've taken to killing them as often as I see them, though I know that makes only a minimal difference. One thing that might help is the elimination of Tree of Heaven (ailanthus altissima). This invasive tree species from China is the favored refuge of SLFs. They eat the tree's sap and lay their eggs on it, preferentially. If landowners, both public and private, were to remove this tree from their properties it could potentially help reduce the impact of these pests.