Invasive Bugs Could Be Coming For CA’s Grapes, Fruit: Study

CALIFORNIA — A certain invasive bug could soon pose a threat to California’s rich wine country and other fruit crops across the vast agricultural state.

The inch-long spotted lanternfly was predicted to reach the state by 2027 if preventative measures are not taken, according to a study published Wednesday in the journal Communications Biology.

In the report, researchers from North Carolina State University used simulation tools to track how far the invasive spotted lanternfly could multiply across the nation. Without mitigation, the bug could be found across the entire country by 2037.

Lanternflies first appeared on the eastern US coast in 2014 in Pennsylvania, most likely arriving on a shipment of goods from Asia, according to Dr. Michael Raupp, insect specialist with the University of Maryland Extension, also known as “The Bug Guy” for his popular “Bug of the Week” blog. The invasive species was first reported in Maryland in 2018.

“Lanternflies are lethal to vineyards,” said Raupp. “While an infestation won’t kill trees, they can become a real nuisance. The honeydew, with its high sugar content, attracts stinging insects like wasps and honeybees.”

The nation’s grape production is valued at $6.5 billion and California alone provides 82 percent of the US grape crop, according to the study.

“This is a big concern for grape growers; it could lead to billions of dollars of losses in the agricultural sector,” the study’s lead author Chris Jones, research scholar with the NC State Center for Geospatial Analytics, said in a press release. “With this study, we have a baseline that we can use to evaluate the effect of different management strategies.”

The nation’s rail line could be contributing to the spread of the insect, researchers said. Also, the presence of a host tree — “the tree of heaven” — which grows along rail lines could be a contributing factor.

“We assumed that the spotted lanternfly needs tree of heaven to complete its life cycle,” Jones said. “The presence of tree of heaven, along with rail networks, seem to be two factors that could drive spread to California. The temperature there is relatively suitable across the state.”

The spotted lanternfly is native to China and is known for its appetite for the sap of grape and almond crops. During feeding they produce large quantities of waste, called “honeydew” because of its rich sugar content. The honeydew serves as a base for growth of a sooty mold that impairs photosynthesis and disfigures fruit and leaves.

“It’s hard to say in advance exactly what the spotted lanternfly’s impact will be on the grape-producing regions of the West Coast, since we only have data from cold-producing regions,” Jones said. “In Pennsylvania, we’ve seen vineyard losses from the double whammy of cold and from spotted lanternflies feeding on the vines. But we do know producers can also experience losses because of the mold growth alone.”

As of August 2021, there are declared infestations and isolated sightings of the spotted lanternfly throughout the mid-Atlantic region. “I have heard they may be as far south now as South Carolina,” Raupp said.

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