One of the prices of living in a globalized marketplace is the heightened risk of a strange insect pest arriving on our shores to belly up to the plant bar. Such an arrival can be big trouble for gardens, the horticulture industry, and the farming and timber sectors.
The latest worrisome organism is a strange insect from East Asia named the spotted lanternfly. The adult is quite pretty, mauve with black speckles. If it were rare, it might be cherished for its ornamentation, but it reproduces in such numbers that it is simply too much of a bad thing.
The adult resembles a moth, but it is neither a fly nor a moth. It belongs to a class named the planthopper, a sap-sucking pest found for the most part in the tropics. Although there are native planthoppers, none is as large as the spotted lanternfly nor potentially as destructive.
It was found in southeastern Pennsylvania in 2014, and more than a dozen counties are quarantined, meaning companies that move material and trucks within and outside the zone need a permit. (The Pennsylvania Department of Agriculture and Penn State Extension have assembled advice to homeowners at extension.psu.edu.)
Last year, the pest was found in Winchester, Va., where it probably arrived on a shipment of landscape stone. The lanternfly overwinters as barely visible egg masses; they look like flat, pale-gray lichens and are easily missed. In late May, the Virginia Department of Agriculture and Consumer Services implemented its own quarantine for Frederick County and Winchester.
The pest now seems established on the northern fringe of the city. I asked Mark Sutphin, the county extension agent for the area, if he could show me this new lanternfly presence. When I met him at his downtown office, he suggested he drive to the location to avoid the risk of me carrying the pest back to metropolitan Washington on my vehicle. The planthoppers can’t move great distances by flying or hopping, but they are consummate hitchhikers.
We went to Fort Collier, a historic property just north of the city line, and famous until now as the site of the 1864 Third Battle of Winchester, not as lanternfly ground zero. The Confederate defensive earthworkings are still evident around the property’s farmhouse.
In the hedgerows, the fecundity of the pest is soon apparent. Sticky traps on tree trunks are smothered in dozens, hundreds of hapless lanternfly nymphs. There are plenty, not on the traps but on the branches of the woody vegetation. We find them in a second and third stage of development — they are black with white spots and maybe half an inch long. In their final pre-adult stage, the nymphs take on a red coloration. Even these juveniles are strong hoppers. They like to stop and stick their strawlike mouthparts into the vascular system of a tree or shrub, and feed like hungry teenagers on milkshakes.
If you were to find something positive to say about the spotted lanternfly, it is that it does not bite us, suck our blood or give us disease. Another plus is that its preferred host is the misnamed tree-of-heaven (Ailanthus altissima), itself an introduction from China that has now widely naturalized.
If lanternflies fed just on tree-of-heaven, all to the good, but the insect is known to sup from about 70 species. The mass feeding can seriously weaken its host. It likes grapevines and fruit trees, and afflicted plants suffer a much-diminished harvest. Winchester, apart from being the hometown of Patsy Cline, is known for its apple industry. The Route 50 corridor between Winchester and Washington now seems dotted with vineyards and destination wineries, whose owners must be worried.
The pest is also attracted to oaks, black walnuts and maples — high-value species for the timber industry.
If the lanternfly moves into your garden, the biggest problem may not be its weakening of ornamentals. When I was standing next to one hedgerow, I could feel what I thought were spots of rain. No, this was lanternfly excreta. The insects exude a sugary waste called honeydew, and in their great numbers, this becomes excessive. On one wall of vegetation, leaves were glossy wet, as if sprayed with a hose. Other insects excrete honeydew, but I have never seen such a dousing.
Within a few days, honeydew draws a black fungus called sooty mold. In the yard, this can discolor decks, patio furniture, play equipment, arbors, vehicles and the rest. When the mold settles on leaves, a plant’s powers of photosynthesis are compromised.
New pests come and go. The Japanese beetle remains a pain in the neck, the brown marmorated stink bug doesn’t appear to be the scorched earth horror it portended. The emerald ash borer is an unmitigated disaster.
As for the lanternfly, “unfortunately, this is going to be a bad one,” Sutphin said. “It’s a pest of numerous agricultural crops, it’s a pest of the forest industry, and it’s a major nuisance in the home landscape.”
A couple hundred feet from where we are standing, a freight train is parked and idling, soon to move off. On the other side, a field is being cleared with grading equipment for a new development. Industrial yards abound, full of big trucks coming and going. Containing this hitchhiker will be difficult.
In the infested area, Sutphin and others are in the process of killing smaller trees-of-heaven and applying systemic insecticide to the larger ones. This is still the tree the pest is drawn to the most.
For now, it’s contained to a relatively small 17-square-mile area of Virginia. The Pennsylvania outbreak appears to have spread to parts of Maryland, New Jersey and Delaware. The biggest thing folks can do, Sutphin said, is to familiarize themselves with the life stages of the insect and report sightings to the Virginia Cooperative Extension service.
The insect is here to stay, Sutphin believes, but its future is not predictable. Birds could learn to like it, and scientists may develop biological controls against it. Government scientists are studying whether a species of parasitic wasp from China could be used to knock down lanternfly numbers. There are reports of fungal pathogens attacking this planthopper.
Nothing remains constant in the natural world, except our ability to mess it up.
A second sowing of carrot seeds now will yield a harvest from late summer into the fall. Carrot seeds need constant moisture and a crust-free soil to develop. Use fresh seed and backfill seed rows with sand mixed with finished compost.
— Adrian Higgins
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