This Thursday, Sept. 19, 2019, photo shows a spotted lanternfly at a vineyard in Kutztown, Pa. The spotted lanternfly has emerged as a serious pest since the federal government confirmed its arrival in southeastern Pennsylvania five years ago this week. (AP Photo/Matt Rourke)

(KRON) — Masses of spotted lanternfly eggs were intercepted at the California state line earlier this spring, according to the California Association of Winegrape Growers. The egg masses were intercepted at the Truckee Border Protection Station in late March on a shipment originating in New York and bound for Sonoma County.

Spotted lanternflies (SLF) are an invasive planthopper species native to Asia. First discovered in Pennsylvania in 2014, the flies feed on the sap of grapevines while leaving behind a sticky honeydew residue on clusters and leaves.

“Their activities stress the plants, decrease vine health, and in some cases, can lead to plant death,” said Natalie Collins, president of the California Association of Winegrape Growers.

The egg masses intercepted in March were found on a 30-foot-tall metal art installation. Inspectors found 11 viable egg masses on the art piece and refused the shipment entry into California. The rejected shipment returned to Nevada and officials further inspected the artwork, finding 30 more egg masses.

The art piece was hot power washed with detergent under the supervision of officials. The shipment returned to Truckee station and was released with a Warning Hold Notice to allow further inspection.

On April 4, the owner of the sculpture allowed county staff to open hollow beams and use cranes to move parts of the artwork for further inspection. Three more egg masses were discovered at that time.

If other spotted lanternfly egg masses made it into California undetected, they could produce adult SLFs in the coming weeks, officials said. Peak populations of the pests are expected in late summer or early fall, with the potential to impact the winegrape industry.

The adult SLF is typically visible from July to November. They have the ability to fly, but not very far. At rest, with their wings folded, the flies are a dull tan-gray color with black spots. When they take flight, the adult’s wings open to reveal a bright red, black and white pattern.