Below you’ll find the second part of a three part series describing the Top 10 insect-related stories of 2014 from Wisconsin. Part three will be released next week.
7) Missing Pests: As every landscaper and farmer knows, there’s a certain batch of insect pests that tend to pop up consistently each year. One of the biggest stories of 2014 was the scarcity of some of these “regulars” like the gypsy moth and the Japanese beetle. The reason behind this? We likely have Mother Nature to thank. Gypsy moth populations fare poorly during periods of wet weather due to the proliferation of a fungal disease that kills the caterpillars. We certainly had abundant and consistent rainfall in 2014, and several images of diseased insects made their way into the lab. In addition, gypsy moth numbers have been in a general decline for several years in the state, which is good news for oak trees.
If there’s one good thing that came out of the brutally cold winter of 2013-14, there’s the fact that it may have helped knock down the Japanese beetle populations. Japanese beetles overwinter as white grubs in the soil and tend to move just deep enough to avoid the frost line. With the pipe-bursting cold and deep frosts of last winter, it seems that the deep freeze knocked their numbers down. As a result, reports of damage from Japanese beetles were scarce this past summer. While it’s too early to tell, it’s possible that it may only be a one-year reprieve. Turfgrass researchers have reported decent grub numbers in turfgrass areas this fall, which could mean that Japanese beetle numbers could creep back up in the future.
Agricultural pests were also down in 2014, with no major pest outbreaks. Two of our best known corn pests, the European corn borer and corn rootworms, had very slow years. Even migratory crop pests, such as the potato leafhopper and black cutworm, which overwinter in the gulf coasts states and migrate northward in the spring failed to take off in 2014. (A full summary of agricultural pests can be found here.)
6) Interesting “Structural Pest” Trends: Two of our insects that commonly invade homes in the fall (boxelder bugs and multi-colored Asian lady beetles) had drastically different trends this year. Box elder bugs thrive under dry conditions, like we had in the latter parts of 2012 and 2013. Similar to the gypsy moth mentioned above, the damp conditions in 2014 likely helped keep the box elder bug number in check and prevented the widespread numbers that we’ve seen the past few years. While the numbers of box elder bugs were low this fall, the multicolored Asian lady beetle, which had been low for the past few years, started popping up in decent numbers in certain parts of the state. One warm October day, I wandered out to the front of the entomology department building on campus to view thousands of the lady beetles flying around looking for overwintering spots.
5) Invasion of the Copper Underwing: Most folks have never heard of a moth called the copper underwing. Rightly so, as it tends to be a fairly obscure species. The caterpillars are commonly called the green humped fruitworms and can feed on fruit trees and other trees. When adults rest on trees, their grayish appearance isn’t much to write home about. However, when they display their hind wings, you’d notice the brilliant copper color and understand the common name of the insect.
For whatever reason, 2014 seemed to be perfect for this species. Perhaps I should have suspected that the few adults I spotted at my porch lights in late spring were the beginning of a trend. As the summer went on, I started getting reports of large numbers of these moths congregating on the sides of homes, sneaking under siding, and even leaving excrement stains on siding. All in all, I had reports of “home invasions” from over a dozen counties, mostly in the southwestern part of the state. Because this species tends to be present in low numbers, I suspect that we won’t see them amassing by the thousands again anytime soon.
Part 3: Coming soon