Five More Pests to Keep an Eye On

Figure 1: Beech leaf disease

Beech leaf disease is ravaging our forests. A recent article in the Providence Journal by Alex Kuffner describes just how bad an impact BLM is having on R.I. forests. First detected in Ohio in 2012, this plant disease is relentless. It interferes with chlorophyll production and starves beech trees to death.

The beach tree is a “foundational species” in New England forests. It produces a high-fat nut for black bears and other animals to eat, a place where woodpeckers can forage, and homes for

animals to nest and raise their young. A beech tree can live up to 400 years.

BLM is invisible to the naked eye. The only way to spot the plant disease, says Kuffner, is to cut the leaves open and then wet the area. Thousands of nematodes (worms) will exit the leaf. The nematodes winter over in the beech’s long, cigar-shaped buds and attack leaves as they emerge in the spring.

That effort interrupts the leaves’ ability to photosynthesize and produce food. No known cure for this disease exists. But research projects are underway to combat it. One problem confronting research scientists in this area is the lack of funds that could help tackle the issue.

Below are four other plant pests Rhode Islanders need to be alert to:

• Spotted lantern fly — This pest attacks plants and trees. The adult fly features spotted patterning, scarlet underwings, and yellow markings on the abdomen. It also has semi-transparent forewings. Adults are an inch or so long and active from August until the first late hard freeze, which occurs around late October into November. While the SLF can survive independently, it mainly spreads through human movement. The SLF was first detected in Pennsylvania in 2014

SLF is invasive. It lays its inconspicuous egg masses on pallets, vehicles, and other goods. So, inspect any shipping materials you get and abide by travel restrictions when moving through areas quarantined for the SLF. If you go to states with SLF, check your gear and equipment thoroughly before leaving and scrape off any egg masses. If you spot one in RI, take a photo, squash the insect, and then make a report to RI DEM’s agricultural pest alerts website.

Emerald ash borer

• Emerald ash borer beetle — EAB attacks American ash trees. Responsible for destroying millions of ashes in 30+ states, EAB is native to Asia. It arrived in the U.S. hidden in wood crates and wood packing materials. Scientists first identified the EMB in southern Michigan in 2002. Since then, it has spread throughout the country. While no cure exists for EMB, several treatment options are available for controlling EMB’s spread. Since pesticide regulations differ from state to state, homeowners should contact their state department of agriculture for the best option in their state.

Asian longhorned beetle

• Asian longhorned beetle — This pest threatens hardwood trees. It can cause more damage than Dutch elm disease, gypsy moths, and chestnut blight combined. No cure exists for ALB, so early identification and eradication are critical. It infests New England, New York, and Ohio areas, threatening recreation and forest resources valued at billions. It’s destroyed millions of acres of this country’s hardwoods in national forests and backyard trees. These pests live in firewood, solid wood packing material, branches, logs, stumps, and wood debris and trimmings.

Box tree moth

• Box tree moth — BTM is invasive. Thriving on boxwood trees as caterpillars, it originated in Asia, migrated to Europe, and now threatens the U.S. It was first spotted in North America in Canada in 2018. It decimates both wild and ornamental boxwoods. BTM caterpillars feed on the underside of leaves, giving them a “peeled” appearance from the top.

Mature caterpillars eat the whole leaf but not the midrib. It can lead to complete defoliation. BTM can web together leaves and construct silken retreats. BTM eggs appear pale yellow and aid in groups of 5 -20, overlapping like shingles. If the infestation is small, hand-picking the caterpillars and disposing of them in soapy water is effective. You can also knock them off with a strong jet of water, which eventually kills the pest.

Additional threats to R.I. forests include winter moth, Lymantria dispar (formerly known as gypsy moth), Southern pine beetle, oak gall wasps, and hemlock woolly adelgid. 

If you spot one of these pests or think you’ve seen a pest not native to Rhode Island, let DEM know as soon as possible.