Highly invasive disease threatening trees all across New Jersey and Pennsylvania

First, it was spotted laternflies. Now, it's a highly invasive disease that could be affecting trees at neighborhood parks, college campuses, and nature parks all across New Jersey and Pennsylvania. 

Horticulturists say beech leaf disease is rapidly spreading across the area, causing beech leaves to darken and crinkle, which ultimately prevents photosynthesis and kills beech trees. 

SKY FOX drone flew high above the District Township Conservation and Recreation Area in Berks County where forestry experts say many beautiful beech trees are being killed. Emilie Swackhammer, horticulture educator at Penn State, says experts are struggling to keep up with the spread of the disease. 

"Research is trying to get out ahead of it, but it can be present for a couple of years before anyone notices it and I think the disease has the advantage right now," Swakchammer said. 

A big concern is that the disease can't be spotted in its early stages. The culprit of the beech tree killer is not visible to the naked eye, making it difficult for horticulturists to recognize it before it's too late.  


Swackhammer says beech leaf disease is caused by a tiny microscopic round worm called a nematode. The nematodes infest the beech tree leaves and eventually take over the entire growth until the leaves curl and fall off, a process that retired horticulturist, Rudy Keller, says is dramatic and noticeable once the tree is infected. 

"It's pretty dramatic if you hold the young leaf up to the light," said Keller as he examined infected beech leaves. "There are alternate light and dark areas and the dark areas contain the disease."

FOX 29's Dawn Timmeney walked down a trail at the conservation area alongside Swackhammer and Keller, only to be saddened by the devastation the disease has caused. 

"If a tree doesn't have leaves. It can't photosynthesize," said Swackhammer. "It really can't tolerate it very long until it uses up all its energy and dies."

Experts are also warning that it's not just beech trees in nature preserves that are dying. European beech trees, which can be found right on college campuses, like Kutztown University in Berks County, are also being threatened. 

Ornamental beech tree at Kutztown University.

"We always hope there's some sort of natural enemy or bilogical control that will start acting on the disease, but we haven't seen evidence of that, but Mother Nature sometimes helps us with that, said Swackhammer. "We're hoping, but we don't know."

Several treatments have been tested, but there isn't a known cure at this point. 

Anyone with a beech tree in their backyard is advised to keep an eye on it. If you notice a thinning canopy, or a change in the coloration of the leaves, experts suggest calling an arborist.