Invertebrates
Spotted Lanternfly
Lycorma delicatula · also called spot clothing wax cicada
On a summer tree trunk in eastern Pennsylvania you might find fifty of them lined up head-down, grey wings folded, drinking sap — and when you wave a hand, a dozen flash bright red and hop away. The spotted lanternfly is one of the most disruptive insect invasions the United States has faced this century, and it arrived, most likely, as a clutch of eggs on a stone shipment.
Overview
Lycorma delicatula is a planthopper, not a fly, native to eastern China. The adult is about 25 mm long with grey-brown forewings marked by black spots and hidden scarlet hindwings. It feeds by pushing a needle-like beak into bark and leaves and drinking sap, favouring the invasive tree-of-heaven but attacking more than a hundred plant species, including grapevine, walnut, maple, and fruit trees.
Why it matters
Lanternflies feed in dense clusters and excrete a rain of sugary honeydew that coats everything below an infested tree and grows black sooty mould. This fouls crops, kills grapevines, and makes yards unusable. The insect threatens vineyards, orchards, hops, nurseries, and the hardwood timber and maple syrup industries across the north-east and midwest.
A hitchhiker
Adults are poor fliers and nymphs cannot fly at all, so the insect spreads mainly by human transport. Females lay grey, mud-like egg masses on any hard surface — tree bark, rocks, patio furniture, and especially vehicles — and an egg mass laid on a car in an infested county can hatch hundreds of kilometres away. Quarantine zones now ask residents to inspect their vehicles before travelling.
Status
The spotted lanternfly is Not Evaluated and is not a conservation concern — the opposite. First detected in Berks County, Pennsylvania, in 2014, it has spread to more than a dozen states despite quarantines and public squashing campaigns, and the management goal is simply to slow it down.
Spotted Lanternfly: common questions
Is the spotted lanternfly actually a fly?
No. It is a planthopper, a member of the insect family Fulgoridae within the order Hemiptera, which makes it a relative of cicadas, leafhoppers, aphids, and true bugs rather than of houseflies. Like all of those, it feeds by piercing plant tissue with a slender beak and drinking sap, and it has sucking mouthparts rather than the sponging mouthparts of a fly. The lanternfly name is applied across the Fulgoridae because some tropical members have an inflated, snout-like head that early naturalists wrongly believed was luminous. This species has no such head and does not glow.
Why is the spotted lanternfly a threat to agriculture?
It feeds in large groups, sometimes hundreds on a single trunk, drawing off so much sap that it weakens or kills the plant. Grapevines are especially vulnerable, and vineyards in south-eastern Pennsylvania have lost vines and suffered reduced yields and winter hardiness. The insect also excretes copious sugary honeydew that coats foliage and fruit and grows black sooty mould, which blocks photosynthesis and makes crops unsaleable. Beyond vineyards it attacks hops, tree fruit, nursery stock, black walnut, and maples, putting timber and maple syrup production at risk, and the sticky mess disrupts outdoor life in infested neighbourhoods.
How does the spotted lanternfly spread so fast?
Almost entirely with human help. The adults are weak fliers and the nymphs cannot fly at all, so natural spread is slow, only a few kilometres a year. But females lay their eggs on any flat hard surface, including the undersides of cars, truck beds, trailers, patio furniture, firewood, and pallets, and the grey mud-like egg coating is easy to overlook. An egg mass laid on a vehicle in an infested county can hatch hundreds of kilometres away weeks later. This is why quarantine zones require residents and businesses to inspect vehicles and outdoor items before travelling.
What should you do if you see a spotted lanternfly?
In areas where it is established, agriculture departments generally advise killing adults and nymphs on sight and scraping any egg masses into a bag or container with hand sanitiser or alcohol. If you find one in a state or county where it has not been reported, the more useful step is to photograph it, note the location, collect the specimen if possible, and report it to the state department of agriculture, because early detection at the edge of the range is where control efforts have the most value. Checking your vehicle before leaving a quarantine zone matters more than any single squashing.