The adult spotted lanternfly is a majestic blend of red, yellow, black, white and tan, but this invasive insect from Asia has a voracious appetite for crops and is wreaking havoc in the mid-Atlantic.

The insects haven’t been found in great numbers in the Golden State but researchers at the University of California, Davis, are on the forefront of finding ways to control the tiny eggs of spotted lanternflies in hopes of protecting key international trade relationships and crops. 

“The spotted lanternfly can be a devastating agricultural pest and growers all over the U.S. and the world are worried about the lanternfly from a production standpoint,” said Spencer Walse, an adjunct associate professor in the Department of Environmental Toxicology. “We’re developing treatments to limit the spread of the eggs, which are laid on anything really that’s outdoors.”

Analyzing treatments

Walse, who is also a research chemist with the U.S. Department of Agriculture’s Agricultural Research Service, is working with the federal agency’s Animal and Plant Health Inspection Service, or APHIS, to come up with treatment schedules or fumigation guidelines to curtail the spread of spotted lanternfly. 

He and his lab team are rearing spotted lanternflies and testing different fumigants on the insects inside the Contained Research Facility, a secure campus facility where researchers adhere to strict quarantine protocols as they study invasive plant pests, pathogens, weeds and other threats. It’s the first facility of its kind in the West, and waste there is sterilized on site and showers are required for people, phones and other personal items coming and going to prevent anything from escaping. 

“If we don’t have a facility where we can bring pests like spotted lanternfly into it really curtails how quickly you can get these schedules developed,” Walse said. “We’re right around the corner and, thankfully, because of the facility at Davis, we were able to get on this as fast as possible.” 

Expanding footprint 

Spotted lanternflies appeared in Pennsylvania in 2014 and have spread to 17 states plus the District of Columbia. They feed on more than three dozen types of North American trees and crops, including grapevines, hops and stone fruits. They also secrete a substance that can cause damaging sooty mold and the eggs can be laid on virtually any surface. 

Infestations can increase production costs for farmers, reduce crop yield and potentially disrupt trade corridors, according to the California Department of Food and Agriculture, which has labeled the spotted lanternfly a quarantine pest, meaning the insects may or may not be here but could present economic harm. 

Walse said Australia, New Zealand and Canada have expressed concern about spotted lanternflies entering via imports from the U.S. and asked that research be conducted to find out what fumigants could attack the insects. He does similar work related to stink bugs, maggots and moths. 

“My job is to work on trade barrier for the US horticultural industry and that really extends into all types of agricultural commodities,” Walse said. “There’s a huge need for fumigation in these formal trade channels.”

Walse’s team is focusing on spotted lanternfly eggs as a means to prevent infestations. 

Examining biology and chemistry 

“It’s been really successful,” said Austin Lourie, a Ph.D. student in agricultural and environmental chemistry, who works in the Walse lab. “Coming in we were a little bit concerned because historically, or typically, insect eggs are the hardest life stage to kill.”

A scanning electron microscope provided images showing promising biological details. “We saw right away that they were filled with tons of holes and had like cracks, essentially access points, so that was very positive,” Lourie said. 

The team tested if two fumigants would work controlling eggs after harvest. “It’s kind of the final step in pest management when importing or exporting products from one country to another,” Lourie said. 

Safeguarding trade

APHIS is reviewing the team’s findings, which confirms a treatment plan the agency recommended works and could be modified to use less of the chemical. Sulfuryl fluoride is also another potential treatment. 

“Let’s make no mistake about it, nothing is 100% effective,” Walse said. “The fumigations that we conduct will do an incredible job of limiting the distribution of lanternfly through commercial trade routes. It’s an incredible challenge.”

Should the spotted lanternfly make it into California, fumigating the eggs is one piece in the puzzle of thwarting the spread of the insects. 

“For us here in California, where we have so much agriculture, the risks of a high infestation of pests like this, or the consequences, are really, really large,” Lourie said. “Essentially, we want to make sure that we can keep our agricultural markets open to certain countries by being able to continue to export at-risk products.”