‘Hitchhiker bug’ thumbs its way to First State: New invasive species could harm farm produce

The spotted lanternfly, an invasive pest, has spread to Delaware. According to the Delaware Department of Agriculture, the first confirmed sighting of the bug was in south Wilmington last fall. (Submitted photo)

WILMINGTON — It’s official. The spotted lanternfly, an invasive plant-hopping insect pest, has arrived in Delaware.

According to the Delaware Department of Agriculture (DDA), a dead specimen was collected in southern Wilmington last fall.

“We got a report from someone who saw one, so we went to the location and started looking around,” said DDA environmental scientist Stephen Hauss. “The one we found wasn’t the one that was reported, so we think there was at least two in the area.”

The DDA has taken to calling the pest the “hitchhiker bug.”

“This is because of how it spreads; it can travel on cars, trucks or find its way into boxes that are being shipped,” said Mr. Hauss. “They’re notorious for how quickly they can spread. They first showed up here around 2014 in a single county in Pennsylvania — now they are in 13 counties.”

Mr. Hauss says the DDA is trying to deputize Delawareans and enlist help in spotting the pests and reporting their spread. The agency has serious concern about the potential damage the bugs may cause to the state’s agricultural industry.

The spotted lanternfly is originally from China. In its native range, a host of predators and pathogens help keep its population in check, but in southern Pennsylvania, and now Delaware, there aren’t those same pressures.

“Birds don’t seem as interested in eating them,” said Mr. Hauss. “We’ve seen photos of a praying mantis eat one, but whatever they’re up against in our area, it’s not enough to slow them down.”

In its immature, nymph stage the pest can feed on a wide variety of plants, but it’s not necessarily its eating habits that make it destructive.
“The nymphs can feed on almost anything — they’ve been observed on about 60 different species of plants,” said Mr. Hauss. “They’ve been seen on basil,
roses, walnut trees, hops, apples and peaches — which is of particular interest in Delaware because we have a fair amount of orchards.”

As the bugs feed on the tender shoots and stems of various plants, they excrete a fluid called “honeydew,” explained Mr. Hauss. This thick, sugary substance lands on other parts of the plant and can start causing mold to form.

The spotted lanternfly is rather distinctive looking. They are similar to moths, but black with white spots. The nymphs are small, round and black. As they age, they develop the white spots and a second pair of bright red wings. (Submitted photo)

“The bug doesn’t actually eat the fruit, but it can cause a lot of it to become unsellable because it gets moldy,” he said.

Although the scope of potential damage caused by the species isn’t well-understood, Mr. Hauss said a Pennsylvania vineyard and orchard owner recently testified before his state senators that the pest ruined 90 percent of his grape crop.

“There are similar reports coming out of Korea, where the bug also reportedly spread to,” he added.

Prevention

Luckily, the spotted lanternfly seems to be susceptible to other insecticides that target other plant hopping species.

“A lot of Delaware farmers do already spray insecticides for damaging insects, but whether or not the majority uses types that will be effective against the new pest remains to be examined,” said Mr. Hauss.

Also, spraying different insecticides on a large scale purely as a preventative measure isn’t something the DDA is currently advocating.

“We’re not infested with them yet, so we don’t want people treating all their trees unnecessarily,” Mr. Hauss said. “At this point, we just want to try to keep an eye out for them and monitor their activity.”

Mr. Hauss also points to ongoing research funded by the USDA that is examining the possibility of recruiting some of the natural predators in the pest’s native range to help control the population.

“Unfortunately, all our solutions at the moment are chemical,” he said. “This new research might bring over some of the bug’s natural enemies so we can get some assistance in the fight against them.”

However, with the rate at which they are spreading, Mr. Hauss sees their eventual, widespread presence in the state as all but inevitable within the next two to three years.

“Bugs don’t care about state lines,” he said.

Identification

Since most of the bug’s spread in Pennsylvania has been largely tracked by citizens reporting sightings, the DDA is hoping to replicate that model.

“It’d be much better to have a thousand pairs of eyes looking for these things than just mine and one part-time assistant I have helping me,” said Mr. Hauss.

Fortunately, the spotted lanternfly is rather distinctive looking.

“They are similar to moths, but black with white spots,” said Mr. Hauss. “The nymphs are small, round and black. As they age, they develop the white spots and a second pair of bright red wings. They are kind of interesting looking.”

The mature bugs die at the first “hard frost,” notes Mr. Hauss. The species overwinters as eggs — very difficult to identify “gray smears” on tree bark or other vertical surfaces. Then, they hatch around May and begin feeding.

Residents who catch a glimpse of the pest are encouraged to visit de.gov/hitchhikerbug and report the sighting. The DDA can then collect more information, confirm sightings and track the pest’s spread. Additional photos and descriptions appear on the website to aid in identification.

Delaware Agriculture Week kickoff

Mr. Hauss will be among the many presenters at the 2018 Delaware Agriculture Week starting on Monday and running though Thursday. There, he will further discuss DDA’s plan for addressing the spotted lanternfly’s appearance in the state.

Delaware Agriculture Week is held on the Delaware State Fairgrounds in Harrington. It’s free and open to the public.

For more information and a full list of presenters and topics, visit sites.udel.edu/delawareagweek/

Reach staff writer Ian Gronau at igronau@newszap.com

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