Inchworms, and more….

By Frank Robinson, President & CEO, Lewis Ginter Botanical Garden

Let me begin by saying that there are pockets of the region, specifically in Mechanicsville and Hanover County, where extreme populations of inchworms have emerged this spring. As with anything in the extreme, “too much” is a problem.

If you are reading this post you are most likely a gardener. We all treasure our plants in our gardens. They have meaning and value for us. So, this is not intended to convince those who are overwhelmed with inchworms that they should be thrilled with this spring’s emergence. And for any of us gardeners, when our plants are being seriously damaged, we do feel the need to take appropriate yet responsible action. If your trees or garden plants are experiencing significant defoliation please take note of a paragraph below suggesting some options to ensure their recovery.

An inchworm at the Garden.

I am not an entomologist, so I will not try to answer technical questions in this writing. However, it may be useful to note that the many common names we use for these insects – inchworm, cankerworm, fall cankerworm, etc. –- all refer to a large group of native moths known as Geometers: quite literally “earth measurers” — not a small task an inch at a time! We hope to access the expertise of Dr. Art Evans to answers some of the more specific questions that have been asked through our Facebook page and our blog. Of course your extension agent is also an excellent resource if you have questions about how to manage inchworm populations on your property. Here’s a 3-minute  interview with Art Evans on April 10, 2012, on WCVE radio about these insects.

This  blog post is less about inchworms and more about finding both wonder and comfort in the context of nature surrounding us. I’m concerned about what feels to be an ever growing disconnection between us and the world that sustains us, and carelessness about the language we use to describe what exists around us. Words are powerful and they leave distinct impressions, particularly on young minds.

For me these thoughts began with a short walk in my neighborhood where I encountered these emerald green acrobats suspended from yards-long silk threads awaiting a breeze or a passerby to transport them to a new host on which to feed. Then a precocious 5-year-old visited with an inchworm crawling up his sleeve. I believe it was his first experience and he was uncomfortable, yet wonderfully curious about this little creature.

Next came the front-page article in the Richmond Times- Dispatch written by Katherine Calos.  I have long admired Katherine’s writing, but I sent her an e-mail expressing my concern about the language of some of her sources which seem to me somewhat pejorative — “infestation”, “outbreak”, “invasion.”  These words struck me as though we were addressing something more like a dangerous mutation of avian flu than part of the natural cycle of spring in Virginia.  Katherine shared with me one of the more distressed e-mails she had received in response to the article from a woman whose property was inundated with the worms.  I also overheard a graphic story about inchworms overwhelming the outside of the vehicle and populating the passenger area in uncomfortable numbers. A few days later the Times-Dispatch ran another article by Andy Thompson titled “Seriously, what’s the problem with inchworms?” that featured my perspective.

For the 95 percent of us who are not inundated with these caterpillars, I most importantly want to express that it is easy to fear and overreact to things that we do not understand. (I wonder if our thinking is distorted by mental images created in our youth of the plagues of Egypt!)

My request: when we have these sorts of opportunities, to take the time to learn more and understand that inchworms, or other elements in nature — in reasonable numbers and balance — have a purposeful and productive role in our ecosystem. In this specific case, they provide an early spring food resource for birds, amphibians and reptiles. Later in the season, in their adult form as moths, they are important pollinators of our native plants as well as food for the same species as mentioned above. Birds are more dependent on insects for food than most people think.

It might also be worth pointing out that these Geometer moths are native insects -– nothing like the voracious and highly damaging Gypsy moth imported from Eurasia –- and they have a specific niche in our forests and gardens. While they feed on a broad spectrum of plants, like humans they particularly enjoy the gourmet-flavors of the members of the rose family (Rosaceae), which includes everything from rose bushes to the majority of our fruit trees and flowering ornamentals.

Also, I hope we will take the opportunity with children to introduce them to the many intriguing and fascinating creatures in the natural world and to encourage their curiosity and understanding of the meaningful roles they play beyond a momentary encounter in the outdoors. Pull out those smart phones and make these memorable moments of discovery about natural science like this YouTube contributor did:

We shouldn’t be casual about bathing our gardens and the broader environment in pesticides to manage transitory and often short-term appearances of insects. The toxicity and cumulative impacts of indiscriminate pesticide use endangers all of us, and the quality of what we eat, breath and drink. Too often we tend to be reactive as opposed to big-picture when something is munching on our plants.

Dr. Doug Tallamy, entomologist and professor at the University of Delaware, talks about how accustomed we have become to sterile landscapes — that when we look out our windows we don’t even expect to see varied and robust animal life. A healthy garden and a healthy environment should welcome and encourage a broad spectrum of living beings.

If your property has trees which have been seriously defoliated, chances are they will recover. It won’t hurt for you to give them a little TLC. Over the next 4 to 6 weeks, if possible, be sure to provide an inch to an inch-and–a-half of water on a weekly basis (depending on rain amounts). Some slow release organic fertilizer will also help them overcome the stress that they have endured, (Plant-tone® and Milorganite® are two good options readily available at your garden center.) The biggest concern would be defoliation over multiple springs, draining the trees of all their reserve energy, and then making them vulnerable to secondary infections.

Homeowners and gardeners cultivate vast acreage of land across this country (21 million acres of lawn alone). It is a privilege and joyful enterprise — yet not without its responsibilities.

Respect for and comfort with nature, for us and for future generations, in the end, will benefit us all.