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California PD/GWSS Board Designates Spotted Lanternfly as Pest of Concern

Board Sees Need for Proactive Outreach on Potential Grape Pest
by Ted Rieger
February 04, 2020

The California Department of Food and Agriculture (CDFA) Pierce’s Disease (PD)/Glassy-Winged Sharpshooter (GWSS) Board voted to designate the spotted lanternfly (SLF) as a pest of winegrapes at a meeting in Sacramento on Feb. 3, a required first step to give the Board authority to fund and engage in outreach and education activities to be proactive to prevent this pest from becoming a problem in California.

Although not currently a problem in California, the SLF, (Lycorma delicatula), is an invasive pest from Asia that presents a significant threat to the grape and wine industry. To date it has caused significant damage in Pennsylvania, where 14 counties are infested and under quarantine. The numbers of SLF and its range of infestation have rapidly expanded in the state since it was first detected in 2014 with dispersion taking place along transportation corridors for highways and railroads. Counties have also been under quarantine for SLF infestations in New Jersey, Delaware, Maryland and Virginia; and it has been detected in New York, Connecticut, and Massachusetts.

The PD/GWSS Board has the ability to designate other pests and diseases of winegrapes for Board funding for research and education/outreach activities. CDFA has been closely following the status of the SLF in the eastern U.S. and the Board has had discussions and been given updates on the pest at virtually every Board meeting for the past year. CDFA staff compiled information and completed the checklist process required for SLF designation in Fall 2019. Designation as a pest by the PD Board does not obligate the Board to spend funds on a pest.

SLF Background and Threat Potential

The SLF is native to Asia, found in China, India and Vietnam, and has become a serious pest of the grape industry in Korea. It is known to have over 70 different host plant species, including stone fruits, nut crops, native forest trees- and landscape trees. The invasive “tree of heaven,” (Ailanthus altissima) is a strongly preferred host that is common in California and found in other states. The SLF is a phloem feeder. It damages plants and vines by feeding on sap and weakening the plant. Feeding also leaves a sugary excrement of “honeydew” that leads to growth of sooty mold on grape vines. Feeding results in vine and grape losses, although the SLF does not feed directly on the fruit.

The SLF was first reported in the U.S. in Berks County, Pennsylvania in 2014.  It is suspected to have arrived in the U.S. from China in a shipment of decorative building stone infested with SLF eggs. It is considered a high risk pest due to its mobility, with eggs and adults posing the most risk for movement. SLF egg masses, which resemble a splash of mud, can be deposited on a wide range of surfaces--plants, wood, stone, concrete and metal, including potentially on railroad cars, vehicles and ships. The SLF’s ability to be transported long distances by normal trade and transportation activities make it a concern for grapegrowers nationwide.

CDFA SLF Activities

CDFA has been informing and training county ag personnel involved with GWSS monitoring in California to identify SLF, as well as personnel at CDFA border inspection stations and ports of entry. CDFA will be sending personnel in March to a SLF symposium being held in Harrisburg, Pennsylvania.

During discussion regarding SLF designation prior to the vote, Board members emphasized the need to inform and involve other wine trade associations, other agricultural crops and commodity groups that could be at risk from the SLF, and other state and national agricultural agencies across the U.S. Board members also expressed the need to address the SLF infestations where they currently exist and prevent further spread. 

CDFA PD Control Program statewide coordinator Roger Spencer observed, “The U.S. Department of Agriculture looks for partnerships to address pest issues of major concern. Based on my 40 years of experience with CDFA, the best quarantine efforts happen at the points of origin. If we show concern that this is a pest we don’t want in California, we have a better chance of getting cooperation and action to control its spread.” 

In 2019, CDFA inspectors, who were conducting cargo inspections for Japanese beetles, reported finding a total of 11 dead adult SLFs on cargo planes arriving at California airports in Sacramento, Stockton and Ontario. The flights originated from an airport in Allentown, Pennsylvania, located in Lehigh County, one of the 14 Pennsylvania counties infested and under quarantine for the SLF. It is believed the SLFs flew into the planes during loading activities at the airport in Allentown and later died en route.  

Separately from the PD Board, in 2019 the CDFA provided research funding through the Proactive IPM Solutions grant program for University of California entomologists Dr. Kent Daane and Dr. Mark Hoddle to investigate SLF biocontrol options such as a predatory wasp native to China. 

New PD Board Officers and Members

In other action at the Feb. 3 meeting, the PD/GWSS Board elected the following officers for 2020: Chair Domonic Rossini, Fratello Farming based in Denair; Vice Chair William Drayton, Treasury Wine Estates, based in St. Helena; and Treasurer Randy Heinzen, Vineyard Professional Services, of Paso Robles. New members joining the Board this year are Rich Hammond, Hammond Family Vineyards in Fresno County; and Aaron Lange, director of viticulture operations with LangeTwins Family Winery and Vineyards based in Acampo.  

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