It was nearly 30 years ago that Carole Cheah, research entomologist with the Connecticut Agricultural Experiment Station, released her first batch of tiny lady beetles from Japan to combat an invasive pest that was predicted to devastate Connecticut forests.
That beetle, called Sasajiscymnus tsugae, is only about 2 millimeters long, but it’s been having a big impact on the invasive hemlock woolly adelgid, its exclusive food source.
Also known as HWA, hemlock wooly adelgids first appeared in America in Virginia in the 1950s. The insect reached Connecticut in 1985 and can now be found in 20 eastern states and southern Canada.
HWA feeds on hemlocks’ storage cells and inhibits the tree’s ability to produce new growth, weakening it and making it more susceptible to other environmental stressors.
At first, the damage to forests was alarming, Cheah said.
“All through the '90s into the early 2000s, we were losing trees by the thousands,” Cheah said.
Then, scientists got an idea.
What if a natural predator of the pest could be brought to America and safely released into the wild to help combat the spread of HWA?
A now-retired CAES scientist, Mark McClure, went to Japan to find that natural predator, Sasajiscymnus tsugae, and brought it back to Connecticut.
Cheah said she and a team of state researchers figured out how to breed and rear the beetles for release.
From 1995 to 2007, more than 176,000 beetles were reared at a state lab in Windsor and released in Connecticut.
“It’s really a homegrown project,” she said.
But then, Cheah said, federal funding for the beetle project dried up. Now, “I'm just by myself,” she said.
So she’s turned to other sources for help, “partnering with various foresters and natural resource conservation managers” to continue releasing the beetles, she said.
Today, Cheah sources the beetles from private companies, which costs about $3 per beetle.
The money to buy them comes from a variety of sources. Her latest partners are The Farmington River Coordinating Committee and The Lower Farmington Salmon Brook Wild and Scenic Committee.
"We actually just got these grants [that] has allowed us to get thousands of beetles," she said.
Nearly 30 years after that first batch of beetles was released in Connecticut, Cheah said she believes the insects are helping to protect trees.
“Based on what I've been seeing, the recovery in the forest, recovery of the trees, and the drop in the Adelgid populations, it's been very encouraging,” Cheah said.
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In case you’re curious, Connecticut homeowners looking to combat the spread of HWA are allowed to purchase Japanese beetles and release them on their private property.
