MAINE — Egg masses of the spotted lanternfly (SLF) have been found in Maine and experts are asking people to be on the lookout for all life stages of this new invasive insect.

According to a release last week from the Maine Department of Agriculture, Conservation and Forestry, “SLF (Lycorma delicatula) is an invasive sap-feeding insect from Asia first found in the United States in 2014, in Pennsylvania. The egg masses were found on trees from Pennsylvania (where SLF is established) planted in Boothbay, Freeport, Northeast Harbor, and Yarmouth.”

The release continued, “DACF urges anyone who received goods or materials, such as plants, landscaping materials, or outdoor furniture, from a state with a known SLF infestation to carefully check the materials, including any packaging, for signs of SLF. There are currently known populations of SLF in Connecticut, Delaware, Maryland, New Jersey, New York, Pennsylvania, Virginia and West Virginia.”

“While the preferred host plant of this pest is tree-of-heaven (Ailanthus altissima), spotted lanternfly attacks over 100 species of trees, shrubs, and vines, and has the potential to impact a broad range of agricultural commodities, including apples, peaches, grapes/wine, maple syrup, as well as the ornamental nursery industry,” the release noted.

“These most recent finds call attention to the fact that there are many ways that spotted lanternfly can travel here from other states,” State Horticulturist Gary Fish said in the release. “Early detection plays an important role in the protection of our state’s economic and ecological resources from invasive species, and we ask anyone who may have received shipments of wood, ornamental plants, or any other materials from Pennsylvania or other Northeastern states to help protect the natural resources and agricultural industries of Maine by checking for and reporting any signs of spotted lanternfly.”

“Spotted lanternfly prefers tree-of-heaven which is very rare in Maine,” Fish said in an email Tuesday, Oct. 6. “We only know of a few spots in York County and maybe some in Bangor, but there has never been a concerted effort to survey for tree-of-heaven in Maine. SLF feeds on over 100 other plants. It has been found feeding on birch, maple, walnut, butternut, cherry, willow, dogwood, elm, apple, peach, pear, plum, grapes, etc.”

Scars or anything like that will not be seen from damage caused by SLF, he said.

“It will cause the plant to lose vigor. The real evidence of infestation is the copious quantities of excrement they poop out,” Fish said. “It is honeydew (sugar water) and it covers the stems and many other surfaces and then attracts other insects and black sooty mold will grow on it as well. It causes grapes to be ruined for the wine or fresh market and the sooty mold fouls apples and other fruits.

“It has caused complete crop loss for vineyards in Pennsylvania.”

SLF has the potential to damage vegetable crops and berries, but it has not been a big problem thus far, Fish said.

“It prefers trees and other plants that are producing plenty of sap,” he noted. “The honeydew, sooty mold and loss of vigor are the problems for the nursery industry as well as the work that has to be done to make sure there are no egg masses on trees to be shipped or hitchhiking nymphs or adults. Nurseries with active infestations must apply pesticides to prevent the spread.”

“Penn State is working on finding natural enemies in its (SLF) native China, Japan and Korea. Birds eat them, but because they are so colorful many birds and animals may see them as poisonous even though they are not,” Fish said. “Many systemic as well as contact pesticides are effective to control them.”

A resource on management with or without pesticides is https://extension.psu.edu/spotted-lanternfly-management-for-residents.

Whether Maine winter temperatures are too cold for SLF eggs and/or adults to winter over and where it might survive is still unknown, Fish said.

“Winter survival of eggs will be one determining factor,” he said. “If eggs are under snow, they may survive better than exposed eggs. One other factor we are not sure about yet is whether there are enough degree days in Maine to allow the adult SLF to come to full egg laying maturity before the first frosts kill them.”

According to a fact sheet on SLF from Cornell University New York State Integrated Pest Management, spotted lanternflies, true bugs, molt to progress between stages. Egg laying occurs from September to November or until the first killing freeze. Eggs hatch in May and June. The first three nymph or instar stages begin then and go through June or July. These instars are black with white spots with the first about 1/4 inch and sometimes mistaken for ticks. After molting, which can occur in July through September, the fourth instar takes on a red coloration with white spots and can be up to 3/4 inch. The adult stage emerges from July to December.

“We really don’t know what will happen in Maine,” Fish said. “It appears that egg laying will be about two months after molting, but this is where we are not certain what will happen in Maine, especially away from the coast.

“No analysis has been done of the annual economic impact SLF could have in Maine if it were to become established.”

There is speculation that SLF won’t be able to complete its life cycle in Maine, he added.

Anyone who thinks they might have found life stages of SLF are asked to mark the spot where they found them, take clear pictures and send the pictures to bugwatch@maine.gov or to call Fish at 207-287-7545.