This is #2 in my series “News from the Woods.” These weekly summaries include observations from daily jaunts, photos and discussion of seasonal woods events, and sources for ongoing education. For regular updates from the field and forest, please visit my Snapshots page.
This week: Bad Bugs and Winter Greens
I have a personal issue with ticks – and what outdoor enthusiast doesn’t fear Lyme disease these days! I’m also concerned about hemlock woolly adelgids, gypsy moths, emerald ash borers, beech scale, and all the rest of the invasive bad bugs.
The goal here is to take a brief look at the effects of an extra cold winter on the life cycles and numbers of pesky insects. In future posts, I will provide a more comprehensive review of various species and their impact on our forests.
Reminder: Let’s not forgot to appreciate and enjoy the winter woods! I have included more of my favorite winter woods greenery.
Bad Bugs and a Cold Winter
So does an exceptionally cold winter (at the very least, the first six weeks of 2018 were exceptionally cold in western PA) wipe out high numbers of these pests? It seems that the answer is somewhat, maybe, no, and it depends.
Although in controlled lab experiments a significant number of ticks will be killed by extremely cold temperatures, they actually have built in physiological traits and behavioral strategies that allow them to survive better in the wild. Instead of cold, it seems that the best control comes from extreme changes in temperature (freezing and thawing cycles) rather than sustained cold. Learn more at Good Natured.
The emerald ash borer has wiped out entire populations of white ash trees throughout the northeast and upper Midwest (Note: One percent or so of the white ash may be resistant). Based on this systematic devastation of our trees, it’s not surprising to learn that normal cold doesn’t have a significant impact on their mortality. Once temperatures reach the -20° to -30°range, there will be a die-off, but we don’t routinely experience those temperatures where the invaders have taken up residence. The Upside of the Bitter Cold: It Kills Bugs that Kill Trees provides more information.
A University of Wisconsin Extension article, The Root of It All: Cold weather effects on insects describes the effect of extreme cold on different invasive insects. On gypsy moths:
“One exception is gypsy moth. The eggs of gypsy moth can be on the exterior surface of homes, recreational vehicles, outdoor furniture and, of course, the bark of oak or other trees. There are several hundred eggs in a mass covered with a tan fuzzy material, which does not offer much protection from cold. If the temperatures reached -20 degrees it is possible that eggs were killed.”
But how frequently do most areas in the northeast and upper Midwest reach -20°! In western PA, extreme cold is anything that typically drops below 0° and remains there for any length of time. It’s good to know that there may be some gypsy moth control during extreme weather conditions, but it’s clear that it’s a limited factor.
Last week, in Weather Challenges and Winter Greens [link], I mentioned the importance of appreciating the winter woods. I’ve added a few more pictures of my favorite green sites in the fields and forests this time of the year.
Woods News and Information
Over the past decade or so, I’ve been a frequent visitor to PA State Game Lands #26, located in the Blue Knob area. What a beautiful place for hiking, photography, and observing wildlife! There is plenty of parking at access points, the roads are well maintained (although not always open for driving), and many options are available to visitors besides, of course, hunting.
Here is some of what is provided at the Pennsylvania State Game Lands (resources and options vary):
- Public shooting ranges
- Seasonal roads
- Access for Hunters with disabilities
- Designated routes for horses and bicycles
- Snow mobile trails
For maps, details, and options based on your location, visit Pennsylvania State Game Lands.