The year-end stats are in: a grand total of 2,092 insects, mites, spiders and other curiosities were submitted to the Insect Diagnostic Lab in 2014. With the ubiquity of smart phones and internet access, nearly 60% of the cases handled in the lab this year consisted either solely of digital images or as digital images accompanying a physical specimen. While the vast majority of cases came from within Wisconsin, there were occasional images and questions sent in from other states and even other countries (including Mexico, England, Ireland, South Africa, India, Guatemala, the Philippines, Spain, Portugal, Afghanistan, and Jamaica).
When it comes to the insects in Wisconsin this past year, several stories pop out. First of all, several of our “usual” pests were noticeably down this year: gypsy moth, Japanese beetle, and box elder bugs, to name a few. In contrast, the emerald ash borer had quite a year and was detected in many new locations, leading to over a dozen counties being added to the quarantined zone in the state. Then there were some cases that seemed to appear overnight: the spring mosquitoes and the massive mayfly hatch in late July.
Below you’ll find the first part of a three part series describing the Top 10 insect-related stories of 2014 from Wisconsin. Parts two and three will be released over the next two weeks.
10) Mosquitoes: Our unofficial “state bird” made news headlines across the state starting Memorial Day weekend. In some spots, the mosquitoes were so bad, that outfitters of recreational canoeing trips were turning customers away, lest they fall victim to the winged vampires.
What caused the mosquito problems in 2014? It boils down to some ideal conditions, as far as the mosquitoes are concerned. With over 50 species of mosquitoes in the state, each species has its own unique habits. Some rely on the moisture from melting snow to develop. Others wait for rain to flood depressions in the woods, where female mosquitoes had laid their eggs. Some other species rely on more permanent bodies of water, such as drainage ditches and rain-filled containers. With the late snowmelt and the heavy rains this spring and summer, our mosquitoes had plenty of moisture to use.
If there’s a silver lining of the 2014 mosquito season, it’s that the number of West Nile cases were down in the state. It turns out that our heavy rains created temporary pools out in the woods, which are favored by our “floodwater” mosquitoes. For the most part, these species are a nuisance, but don’t carry diseases like West Nile. The mosquitoes that spread West Nile tend to prefer more permanent bodies of water. When you have lots of rain, it can sometimes cause these more permanent bodies of water to overflow, flushing the mosquitoes away. It may be counterintuitive, but our worst West Nile year of the past decade was actually the droughty year of 2012.
9) Invasive Leaf Beetles: Two different species of invasive leaf beetles (Family Chrysomelidae) were detected in Wisconsin this past year: the lily leaf beetle and the viburnum leaf beetle. Both of these beetles have unusually similar histories: they’re both known from Europe but were found in Canada in the mid-1940’s. Both made their way into New England in the 1990’s and have been popping up in other locations since then.
The lily leaf beetle was detected for the first time in Wisconsin in July in the Wausau area. This species feeds on true lilies in the landscape and has been found at a handful of sites in Marathon and Wood counties. The viburnum leaf beetle had technically been found once before in the state a few years ago in Dane county. At the time it had been found on a recently planted viburnum bush, which was removed and the insects were eradicated. Technically, the case that popped up in the Milwaukee area in late summer on an established viburnum bush is our second record in the state. Unfortunately, the original source of the insects and extent of the current infestation are not fully understood at this point.
While these two beetles have only been found in a few isolated spots in the state, they have the potential to cause significant damage to their host plants, so gardeners should keep a watchful eye out for them in 2015!
8) Brown Marmorated Stink Bug (BMSB): This invasive pest was first discovered in the state in 2010. When I describe BMSB during presentations, I joke that it’s as if a mad scientist in a bad Sci-Fi movie had somehow crossed a Japanese beetle with a box elder bug. Like Japanese beetles, BMSB will feed on hundreds of different types of plants: field crops, vegetables, fruits, and ornamental plants can all be damaged. In addition, BMSB has the habit of sneaking indoors in the fall like box elder bugs. In other parts of the US (such as Pennsylvania and Virginia), BMSM has been wreaking havoc on agricultural producers and homeowners alike. Luckily, this stink bug has been quiet the past few years in Wisconsin and we saw more of the same for 2014. While I only had half a dozen samples documented in the state this year, this is certainly a pest that everyone should be keeping an eye out for in the future.
Part 2: Coming soon