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Space Invaders

Invasive plants and insects have taken up residence in the Nutmeg State

You may not be in love with pitch pine trees, with their weirdly curved trunks, twisted branches, and needles that can only be described as messy clumps. On the other hand, they are inoffensive, part of Connecticut’s rich natural environment – and happen to be in grave danger because of a newly invasive insect in our state called the southern pine beetle.

Armies of southern pine beetles are capable of destroying pitch pine trees.

“Given the high number of beetles collected last fall, and the relatively mild winter, we’re expecting a higher population of southern pine beetles this spring,” reports Alicia Bray, an associate professor of biology at Central Connecticut State University, and one of dozens of professionals who track and study invasive plants and animals across the state.

“When their populations are high, they are capable of mass attacking healthy pine trees, overwhelming their defenses, and causing their death. What’s more,” she adds, “they have the potential to also attack the red pine and the scotch pine, which could have a devastating effect on native animals that use these trees for food and habitat.”

Which is precisely why Bray and other Connecticut researchers urge the rest of us to report sightings of insects and plants that we may not have seen before. No one wants the Constitution State to become the Invasive State.

Currently, there are about a hundred relatively new invasive plant species and just under a dozen from the insect world here in Connecticut. We’re already dealing with climate change, global warming, the need for cleaner energy, and other social and environmental concerns, so taking on the responsibility to be “invasive detectives” may be a bit of a tall order for the average citizen, considering that few of us have either the time or training to do it well. But if we care about the aesthetics of our gardens and parks, and the health of our birds and bees, then at the very least we should remain aware and contact the right people when we suspect something is amiss.

For example, pitch pine trees have an ability to ooze resin in a not-always-successful effort to entangle the nasty insects before they lay their eggs. So if you want to help protect our pitch pine population, go out and look for some resin globs, which look a bit like popcorn.

Just what makes a species invasive? In Connecticut, these are plants that are not native to the state and have the potential for widespread dispersion and growth. For insects, while there are no official criteria, it’s basically a bug that is non-native, is making its way around, and most of all has potential to cause ecological or economic harm.

By and large, plants in our own gardens, parks, and walkways are fairly easy to keep an eye on, and even remove. With insects, it’s a different story. For one thing, even in our own yards and greenways, we can’t just tell them to leave. For another, we have to be careful what we try to annihilate because, on balance, insects are very important to our ecosystem. We don’t want to upset or inadvertently destroy the good ones!

Interesting Insects

Many insects provide nourishment for our own food sources, pollinate trees, and return nutrients to the soil when they break down dead and decaying material. The Connecticut Science Center in Hartford is even devoting an entire week to the ubiquitous little creatures from July 21-28, while UConn Extension hosts its sixth annual Bug Month event, virtually, in the same month.

Given that more than half of all life on Earth is comprised of insects, it’s no surprise that from time to time a species or two invades our own little corner of the planet. Here’s some data about a few of the more egregious.

Emerald Ash Borer

According to state researchers, this worrisome species was found in Connecticut in 2012, and has since spread to all towns in the state, killing ash trees in its wake. Aptly named, this green beetle produces larvae that feed on the inner bark of ash trees, impacting the flow of nutrients needed to keep the tree alive. Experts say it probably made its way here on ships and airplanes carrying wood packing material. So far, it has killed hundreds of millions of ash trees in North America.

“The basic approach taken by biologists is early detection,” shares James Cowen, a soil and wetland scientist in North Stonington. “Can we control it and limit its spread?”

Cowen doesn’t provide a definitive answer to his own rhetorical question, which merely emphasizes its seriousness. The loss of ash trees reduces vital habitat and allows undesirable invasive plants to fill the gap.

Spotted Wing Drosophila

This pest was first identified in 2011 by Richard Cowles, an entomologist with the Connecticut Agricultural Experiment Station (CAES) in New Haven. “Colleagues subsequently detected its arrival a few weeks later in northern New England, coinciding with Hurricane Irene,” Cowles explains. “The winds undoubtedly blew these tiny flies along the coast.”

It took just three years for the spotted wing drosophila to invade growing regions across America. It has impacted the ability of farmers to successfully grow fruit, especially raspberries, blueberries, strawberries, and peaches.

Unlike similar fruit fly varieties, this one, which originated in East Asia, can lay eggs inside fresh fruit, and it takes just a few days for the fruit’s skin to wrinkle and crater. Uncontrolled, the spotted wing drosophila can destroy at least 80 percent of a single harvest.

Spotted Lanternfly

This is our newest invasive insect, though its population is still relatively small. “It can have devastating effects on our fruit crops,” warns Alicia Bray. The adult spotted lanternfly is about an inch long and has large, multicolored wings, with black spots. It is native to China, India, and Vietnam. Entomologists call it a “hitchhiking bug” that lays eggs almost anywhere during its travels, including on patio furniture and cars.

Hemlock Woolly Adelgid

The hemlock woolly adelgid, which is native to Asia, is an invasive, aphid-like insect that attacks North American hemlocks.  These little bugs can take advantage of the two species of hemlock trees found on the East Coast because the trees have not evolved any defenses against them. “Hemlock trees can grow up to 140 feet tall,” Cowles says, “but can be killed in a few years by an abundance of these one-millimeter-long insects.”

Researchers say the hemlock woolly adelgid probably made its way here from botanical specimens planted in Virginia 70 years ago. Hemlock trees typically provide habitat for many other species, so the dispersal of these particular adelgids has dramatically affected the ecology of forests where hemlocks used to be abundant. What’s more, they remain inactive for much of the growing season and attach themselves to hosts in the colder months – when no one really wants to be outside looking for them.

The insects mentioned here represent just the tip of the invasive bug iceberg in Connecticut. There are dozens more.

Pesky Plants

Not to be outdone, there are 97 individual species of invasive or potentially invasive plants in the state, most of which are prohibited to be bought, sold, transplanted, or cultivated here. The invasive ones include:


Also known as the common reed, phragmites first came to America in the early 19th Century – as seeds hidden in the soil used for ballast in ocean-crossing ships. Once here, phragmites developed into an aggressive perennial wetland grass that easily overtakes native plants and displaces native animals. It has fluffy seed-heads, which makes these reeds exceedingly easy to see. But that doesn’t mean they’re easy to control. They’re not.

Japanese Barberry

This is an attractive species with many cultivated varieties often used in landscape design. It is adorned with yellow flowers in early spring, and pretty green or burgundy leaves. Birds eat their tiny red fruits. “It is also a very adaptable shrub that grows well in everything from full sun to dense shade,” says Todd Mervosh, a scientist formerly with the Connecticut Agricultural Experiment Station in Windsor, who now runs TM Agricultural & Ecological Services, a Suffield-based consulting business that deals with invasive plants.

“The problem, however, is that barberry thickets have been found to harbor higher populations of ticks, which leads to greater risk of Lyme and other tick-borne diseases.” The plant is invasive but not prohibited.

Native to China and Japan, the Japanese barberry was introduced to U.S. gardens as an ornamental shrub a century and a half ago. “In addition to the tick issue,” Cowles adds, “it outcompetes other shrubs, and the spines on its twigs prevent browsing by deer. That’s how it’s able to take over.”

Common Mugwort and Tansy Ragwort

These are two other bad actors on the invasive plant stage that many Connecticut botanists put on their short list of troublesome plants. The common mugwort, which is invasive but not prohibited, is particularly pesky because it is able to grow well in nutrient-poor soil. But the tansy ragwort, a biennial wildflower, can be far more problematic because of its effects on people and animals. “It’s toxic when eaten by some livestock or incorporated into human foods,” says Charlotte Pyle, co-chair of the Connecticut Invasive Plant Working Group. That ill-fated detail may be why this plant is often referred to as a Stinking Willie.

Mile-a-Minute Vine

Experts say this fairly recent arrival can grow six inches per day. Native to East Asia, it seems to have arrived in Pennsylvania in the 1940s. “They spread like cobwebs over trees, are unsightly, and are unfriendly to people and to the natural wildlife that did not evolve with them,” Cowen explains. That means that wildlife is unable to eat or use them in any way.

These vines not only grow as if they’re being filmed by stop-action photography, but they also kill native trees by shading them out, and they weave themselves into wavey coverings that hinder natural regeneration and seeding, like a nasty invasive blanket.

Watchful Eyes

Residents owe a debt of gratitude to the entomologists, botanists, agronomists, and other scientists who keep their eyes open on our behalf. They take their responsibilities seriously – and have been doing so since their careers began.

Richard Cowles, for example, grew up in a family of horticulturists and has several degrees from Cornell and Michigan State in entomology. He worked for the CAES for 26 years.

Alicia Bray at CCSU says she truly enjoys learning about insects, the most diverse and abundant group of animals on the planet. “My interest began at Eastern Michigan University; I needed to take an entomology course to graduate, and I was hooked. I can discover something new about insects every day of my life and still not know a fraction of what there is to know,” she says.

Todd Mervosh’s interest in plants started as a child, helping his parents plant in their vegetable garden. Behind his house was a 10-acre farm and says he was always fascinated by the crops and the weeds growing there.

As for James Cowen, because of the questions he asked in class, his eighth-grade science teacher predicted that he would become an entomologist when he grew up.

And Charlotte Pyle became involved in botany when she interned years ago at Tahoe National Forest in California, where her job was to document rare plant locations. “It was almost like playing detective,” she recalls.

We may never know as much as these folks. But learning more about invasive species will help in efforts to protect our homes, gardens, roads, and parks. We can’t do exactly what they do, but at the very least we can fire off an email each time we see a Stinking Willie.

Joel Samberg is a Connecticut-based journalist, author, and playwright.