ALIEN INVADERS: Fighting the Spotted Lanternfly

Photos by Evan Brandt

The lifespan of the invasive spotted lanternfly is laid out on a slide from last night's presentation on how bad the problem is and how to combat the pest.

The map on the left shows the first five Berks County
townships where quarantine efforts began. At right is the
counties where a quarantine is now in place.

The fight against a pervasive alien insect was laid out in stark terms last night, as well as strategies for fighting them.

First spotted in western Berks County in 2014, authorities have worked to contain the invasion of the spotted lanternfly, an insect native to China and Vietnam, but apparently jumped the Pacific on a pallet of stone delivered to Berks county at some point.

Since its arrival, it has spread from one to 13 counties in Southeastern Pennsylvania and is making inroads into Virginia, Maryland, Delaware and New Jersey.

But things could be worse, said Evan Corondi, an insect expert with the Berks County Conservation District who gave a presentation on the invader at Pottstown Borough Hall Thursday night.

The cluster of red dots show the only places in the state
where spotted lanternfly have been found.

In four years, it has spread to only seven additional counties. When the spotted lanternfly arrived in Korea, it had spread across the entire country in three years, he said.

"So I know it can seem like the effort's not worth it. But it's working. The things we're doing to control it are working," he said to the group of about 90 people who all expressed exasperation with their efforts to eradicate the pest.

One woman, who said she is having eight tree of heaven trees in her yard taken down next week, said the stink from the insects excrement is terrible. "We haven't used my back yard all summer. It smells like a urinal."

The "tree of heaven," which scientists call ailanthus altissima, is itself an invasive  species, which is very hard to kill. It also is from Asia and is the spotted lanternfly's favorite food, although the bug is quickly developing a taste for native North American trees, including fruit trees, valuable hardwoods and grapevines.

This photo shows a backyard tree, at right, covered with
adult spotted lanternfly. At left, the bottom step has been
power-washed, while the ones above remain coated with
the "sooty mold" they excrete.

When they feed, the lanternfly harms trees in two ways. The first is when it pierces the bark to feed on the nutrients in the layer beneath, robbing the tree of nutrients as well as leaving a hole for other insects or disease access to the tree's interior.

The second way is what the insect excretes. Called "honeydew," it is sweet and stickly, but which turns black into what Corondi called "sooty mold," which coats leaves and impedes photosynthesis, as well as emitting the odor referred to above.

Here is video of spotted lanterfly on grape vines, excreting the "honeydew" that can impede photosynthesis:

Egg mass.

The spotted lanternfly has five stages of life, beginning with the gray egg masses, which look like a mass of mud, usually vertically oriented on trees, rocks or even the siding of your house.

The adults are current mating and laying those eggs. Each egg mass contains between 30 to 50 eggs.

They can be hard to spot because when fresh, they are a gray mass, usually laid on an equally gray surface and, as they dry out, turn a dull gray," said Corondi.

Although he said "now is a perfect time to kill the adults," as they are just starting to lay eggs and fewer adults means fewer egg masses.

However, in a few weeks, the masses will mostly be laid and efforts to combat the pest should turn to scraping them off any surface they are seen.

A credit card works best and experts advise having some kind of container or plastic bad to scrape the egg mass into. Once contained, rubbing alcohol will kill the eggs.

An alternative is to crush them," said Corondi, an exercise he admitted he finds particularly satisfying. "They make this kind of popping sound," he said with a smile.

Here is some video of Corondi talking about ways to control the spotted lanternfly, including proper egg-scraping technique:

This exhibit 

shows the spotted lanternfly life cycle.

As the temperature drops, the adults get more lethargic and are easier to kill, but the first or second frost will kill them anyway.

Sadly, the cold does not kill the eggs, which will be mostly laid by late November and will hatch in the spring into small nymphs about the size of a tick.

They grow to about the size of a dime and take on the striking red and black coloring with white spots.

In this state, the lanternfly is actually susceptible to being sprayed with soapy water as the film from the soap can keep the bugs from breathing through their skin. But once they grow wings, this method seems to work less well.

"I've killed hundreds of them with a plan old flyswatter," bragged one member of the audience.

Spotted lanternfly do not pose a risk to human health, but can affect forest hardwood products worth $16.7 billion in in Pennsylvania. 

They like oak, maple and walnut and also affect apple and peach trees, an industry worth more than $119 million. In particular they pose a risk to Pennsylvania's $944 million nursery and landscape industry.
Here is some video of Corondi offering some general information about the spotted lanternfly invasion:



Several kinds of tape, including duct tape with the sticky side facing out, can capture spotted lanternfly at different times of the year because as it turns out, although they are called fly, "they're not very good flyers," said Corondi.

Early stages are most susceptible to being caught on taped trees.

They belong to a group of insects called "leaf hoppers" and spread by climbing tall trees or tall buildings and then leap into the wind to travel a long distance.

Of course they travel the longest distances by hitching rides on our cars, trains and freighters.

A variety of chemical weapons can be used. Several pesticides work, providing you can get close enough to use them.

But one ingenious strategy Corondi outlined is to use one invasive against the other.

A pesticide method calls "systemics" has the lanternfly warrior use a downward stroke to cut some holes in a tree infested with lanternfly and into these holes apply specific pesticides designed for this function.

The tree with take up the pesticide, which the lanternfly will ingest as it feeds on the tree.

Here is video of Corodni talking about how controlling the Tree of Heaven can also help to control and contain the invasive spotted lanternfly:

Corondi with a tree of heaven branch he displayed to familiarize

the audience with the species.

As Corondi said in the video, eliminating all but one or two tree of heaven in a wooded area will
force the lanternfly to focus on the remaining trees.

Using the systemic method then allows you to poison many more lanternfly with less poison, as well as eliminating more of the invasive trees.

Unfortunately, because the trees are going dormant for the winter, this kind of assault must wait for spring.

It's a lot of information to absorb at once. But if you need more, Corondi recommended this link to Penn State Extension's page on the subject.

And here are the Tweets from last night's presentation:


Alien Invasion