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Thousands of acres in Black Hills National Forest show pine defoliation

Kendra Schotzko, USDA Forest Service
Kendra Schotzko, USDA Forest Service
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The culprit behind the defoliation is the pine looper, a moth. While in its catepillar life stage it feeds on pine needles.

7,000 acres of the southern Black Hills are showing thinning pine needles.

The defoliation is visible to the naked eye, but researchers don’t think the trees are dead. Scott Jacobson, who works with the U.S. Forest Service, said this is not the return of the mountain pine beetle.

“Just about two or three weeks ago we were notified by the public that there was an impact on the forest down south of Custer over by Pringle," Jacobson said. "It appears to be a defoliation issue going on. We went out and took a look at it, and in fact pine looper is the culprit.” 

The pine looper is a type of moth that feeds on pine needles during its caterpillar stage.

Jacobson said they’re waiting for scientists to determine the impact.

“The entomologists seem to think the trees will recover with new pine needles in the next growing season," Jacobson said. "In terms of managing the area, we’re going to have to wait and see how the area shapes up after the season and what happens next growing season.”

While the pine looper is a native insect, Forest Service entomologist Kendra Schotzko said they don’t see it often.

"Every so often we do see these increases in our population abundance, leading to very noticeable defoliation or lack of foliage on the trees," Schotzko said. "An important thing to keep in mind with the pine looper in particular is that these large infestations generally only last one to two years.”

Schotzko said there are natural diseases and predators that can quickly knock down pine looper populations.

C.J. Keene is a Rapid City-based journalist covering education, healthcare, arts and culture.