What’s been “crawling” in the UW-Madison Insect Diagnostic Lab this past year? Find out in this three part series.
The State of the IDL in 2016
It was another busy year around the UW Insect Diagnostic Lab. By the end of 2016, the lab had identified 2,444 specimens, slightly up from 2015’s record number of 2,423 specimens. As in 2015, ~95% of these cases came from within Wisconsin, with just over 4% of samples coming from other states and ~1% coming from other countries.
Overall, lab statistics were very similar to other years in the recent past, with roughly half of the lab samples coming in during the months of June, July, and August. The majority of samples consisted of digital images coming in from the general public. County Extension offices and agents accounted for the next largest number of samples, having submitted over a quarter of all samples processed in the lab. Other sources of samples included the green industry, medical and public health professionals, pest control professionals, farmers and agricultural consultants, and other colleagues in the UW system and state or federal agencies.
Very similar to 2015, over 90% of the specimens came from five major groups of insects:
Coleoptera: beetles, such as Japanese beetles and carpet beetles
Hemiptera: “true Bugs”, such as aphids, and boxelder bugs
Lepidoptera: moths, butterflies, and their young (caterpillars)
Diptera: “true flies”, such as house flies and mosquitoes
Outreach efforts of the IDL in 2016 included over 90 public talks at a variety of events throughout the state, over 30 media interviews, and regular appearances on Wisconsin Public Radio’s “The Larry Meiller Show”. Numerous articles and other publications came out of the lab in 2016, including a Wisconsin Bee Identification Guide and an urban pollinator conservation guide to help increase awareness of pollinators and pollinator conservation. The services provided to Wisconsin residents by the UW Insect Diagnostic Lab and its outreach efforts are one of the many examples of the Wisconsin Idea.
Coming soon : Wisconsin’s Top Insect Trends of 2016 (Numbers 10-6)
As is typical in a given year, Wisconsin sees a few new invasive species in the state each year. In 2016, one of the surprises was the arrival of the “two banded Japanese weevil” (Pseudocneorhinus bifasciatus), often simply called the “Japanese weevil”. Weevils themselves are technically a type of beetle from the hyper-diverse family Curculionidae, which contains a plethora of weevils, curculios, and multitudes of bark beetles. When talking to the public, it’s amazing how often the Japanese beetles feeding on landscape plants during the summer are mixed up with the Asian lady beetles (Harmonia axyridis), which invade homes in the fall. Given the name of this new “Japanese weevil”, I’m expecting this creature to confuse the situation even more.
What is the Japanese Weevil?
The Japanese weevil (P. bifasciatus) is a non-native beetle that feeds on a wide variety of landscape plants, particularly shrubs. Adult Japanese weevils are ~ ¼” long with a gray or brownish, pear-shaped body with black bands across the wing covers (elytra). The pale larvae (grubs) live in the soil and feed on roots of suitable host plants. We haven’t had this pest in Wisconsin long enough to fully understand the local life cycle, but given the pattern in other states, this insect will most likely complete one generation per year, with adult presence and feeding damage occurring during the summer from late June through August.
Where’s the Japanese weevil from?
Very similar to the Japanese beetle (Popillia japonica), the Japanese weevil is native to Japan and first popped up in the US in 1914, via the transport of infested nursery stock. Like the Japanese beetle, the Japanese weevil feeds on a wide range of landscape plants. When it first showed up in Wisconsin in 2016, the Japanese weevil was found on a variety of ornamental plants in Madison, WI. How this species got to Wisconsin remains a mystery, but the movement of infested potted plants is the most likely explanation, as this insect is not capable of flight. While the Japanese beetle is common across many parts of eastern North America, the Japanese weevil has a much more scattered distribution and can be found primarily in the Mid-Atlantic region with scattered cases in the Illinois, Iowa, Wisconsin and Oklahoma.
What does this insect mean for Wisconsin?
Luckily, it seems that the Japanese weevil may not be nearly as big of a threat to landscape plants as the Japanese beetle. When lots of Japanese beetles are present, entire trees can have their leaves nibbled into a lace-like skeleton. In contrast, when the Japanese weevil feeds, it tends to cut notches out of the edges of leaves. This damage can resemble the feeding of many caterpillar species, and healthy plants should be able to tolerate the feeding. Reports from other states suggest that this insect unlikely to cause very severe damage.
Think you’ve found the Japanese weevil?
If you come across any beetles in Wisconsin feeding on landscape plants that resemble the Japanese weevil, send digital images and/or physical specimens to the UW Insect Diagnostic Lab for confirmation, so we can track this new arrival in the state.
Ask any gardener or landscaper in the Midwest what their least favorite insect is, and the Japanese beetle will probably be near the top of the list. Think of the plants that this insect feeds on: ornamental trees and shrubs like lindens, birches, crabapples, and roses, fruit crops like apples, pears, plums, raspberries, and strawberries, and garden and vegetable crops like beans and corn, as well as hundreds of other plants. It’s no wonder gardeners have to be on alert for this insect.
So why the resurgence of Japanese beetle activity in 2016? Every winter, a common topic I’m asked about is my “insect forecast” for the coming year. Before winter had even ended, there was good reason to believe that the Japanese beetle would pop back up the state in 2016–and Mother Nature may be the cause. Japanese beetle larvae (white grubs) spend the winter in the soil below ground. In July, August, and September, these grubs can be found in the upper portion of the soil where they feed on the roots of turfgrass. As winter approaches, the grubs tunnel deeper into the soil where they avoid being killed by a hard freeze. In most parts of Wisconsin, we had a reprieve from Japanese beetles the past two years. I suspect this may be due to the brutal winter of 2013-14, which had some extended periods of sub-zero temperatures. It’s quite feasible that this deep frost killed many grubs and led to lower adult populations the following summer (2014). Given enough time, the Japanese beetle populations were destined to rebound at some point, and the mild (el-Niño) conditions this past winter might have been just what they needed to bolster their numbers. Unless we face another brutal winter in the next few years, I suspect that Japanese beetle numbers will be up for the foreseeable future in the state.
Ironically, there’s an important milestone to recognize for this invasive pest this year–the Japanese beetle was detected for the first time in New Jersey 100 years ago, in 1916. Slowly, but surely, this insect spread through many parts of the eastern US, and has been spotted on occasion in isolated spots in the western states. We also have an interesting history of Japanese beetles in Wisconsin. Technically, our first detections occurred in the southeast part of the state in the 1960’s, although these populations struggled to take hold. At the time, this seemed to be a comforting sign–perhaps, our famed “frozen tundra” was simply too cold for them. However, by the 1990’s, Japanese beetles had gotten a solid foothold in the state and they’ve been around much to the chagrin of gardeners ever since.
Interestingly there’s also a new “Japanese beetle” that showed up in Wisconsin this year: the invasive Japanese weevil (sometimes called the “two-banded Japanese weevil”). Stay tuned more information about our newest invasive species in Wisconsin.
Right around this time of the year in Madison and other college towns across the country, a smorgasbord of furniture and other goods appear along the sidewalk as tenants are frantically moving in and out of apartments. For historical reasons related to the need to register for classes in-person at UW-Madison, many of the leases end and begin in Madison around August 14th-15th each year, leading to an abundance of items on the curb free for the taking. This is such a well-known and easily observable occurrence around Madison, that some have even affectionately referred to it as “Hippie Christmas”.
As the old saying goes, “one man’s trash is another man’s treasure” and this certainly could be the case with free things on the curb. That free couch along the sidewalk might look like the perfect addition to that larger apartment, and it can be hard to beat the price of that curbside armchair. However, there’s the real possibility of unwanted hitchhikers: bed bugs. While I’m all for reducing waste, reusing items, and recycling, the concern about bed bugs should not be overlooked.
Until the mid 1900’s, bed bugs (Cimex lectularius), been a common pest around the world. With the invention of synthetic insecticides around the time of World War II, these insects had nearly been wiped out. Given time, bed bug populations developed resistance to some of those insecticides. The insecticide resistance coupled with the rise of international travel and the bed bug’s stealthy stowaway tactics, meant that it was only a matter of time before they came roaring back onto the stage. That very phenomenon has happened in the past two decades, and bed bugs can now be found in every US state, and in a wide variety of situations––from student apartments to five star hotels. When bed bugs are detected, they can be eliminated with diligent tactics, although the task can be challenging and is best left to pest control professionals. Costs to eliminate bed bugs can easily be $1,000 or more.
Absolutely need to have that nightstand from the curb? A few steps can help prevent issues. The first is to simply know how to look for bed bugs and their telltale signs. Many folks seem to believe that bed bugs are too small to be seen with the naked eye, but this is far from reality. It turns out that adult bed bugs are roughly the same size, color, and shape as an apple seed (as shown above). Juveniles will have the same general shape, but will be smaller. Very tiny whitish eggs (~1mm long) and black spots (from digested blood) on furniture are other classic signs of bed bugs. [A useful guide to identify bed bugs and their signs can be found here]. Before bringing any item in from the curb, examining it thoroughly for any signs of bed bugs is well worth the effort in the long run. Found a smaller item you’d like to grab? One easy step for small items is to place them into a large Ziploc bag and put them in the freezer for 7-10 days as a precaution. Bed bugs, or any other insects present in such an item would freeze during that time.
What if you’ve moved into a new apartment and suspect it has bed bugs?Getting a suspected bed bug specimen properly identified is a crucial step. It turns out that there are a number of nearly identical species that can only be told apart under the microscope. These related species are associated with bats and birds; they don’t pose the same headaches as bed bugs and are controlled differently. If you’ve confirmed that bed bugs are present in your apartment, starting a conversation with your landlord is an important step; ignoring the situation is about the worst thing that could be done in such as case. Overall, it’s much easier for a pest control company to come in and eliminate a small bed bug infestation than a large one. This is especially true of large apartment and condo complexes, where bed bugs can spread from unit-to-unit over time, making control much more difficult. In addition, if you happen to be moving out of an apartment that has bed bugs, it’s best to mark any items being discarded with spray paint so that others looking for furniture will know not to bring those items home with them.
For bed bug questions in rental situations and many other tenant-related topics, the Tenant Resource Center of Wisconsin offers assistance. Safe moving, happy curbside hunting, and keep an eye out for bed bugs!
Many naturalists will relate to this post: as nature enthusiasts, everyday tasks sometimes end up taking much longer than expected due to fascinating biological distractions just beneath our feet.
As I was mowing the front lawn over Memorial Day weekend, I stumbled upon a prehistoric-looking stag beetle, which is always a neat creature to come upon. As an entomologist, my first instinct was to pick it up to make a closer examination. Typically, I run into stag beetles a few times each year and it’s usually the large, “reddish brown stag beetle”: Lucanus capreolus (see image below). The beetle I found was a bit smaller, darker, and lacked the bicolored legs of L. capreolus, but was still a good-sized insect at over an inch long. After a beverage break and some Internet browsing, I figured I must have been looking at the closely related Lucanus placidus. Interesting, I thought, and placed the stag beetle back on a portion of the lawn that had already been mowed, lest it face the wrath of a metallic tornado.
Another pass or two with the mower and I spotted a few more stag beetles. I was no longer simply stumbling upon these beetles—something else must be going on. Once again, I stopped mowing to take a closer peek in the taller grass, only to find even more beetles. Within the span of five minutes, I had found nearly forty stag beetles in the lawn near a low spot where a tree must have previously stood. As with the first specimen, I gently relocated these beetles and rushed to finish mowing in the dwindling light.
Around 10:30 PM, I wandered back outside with a flashlight to see what the beetle situation looked like. I had no idea what I was about to stumble upon—hundreds of battling stag beetles! Male stag beetles use their large mandibles to compete for females, which made my front lawn seem like a combination of the Bachelorette mixed with Gladiator. It was astonishing to see the sheer numbers of stag beetles present in a single spot at a given time. In an attempt to count them, I starting placing them into an empty flower pot. The forty I had spotted earlier seemed like a drop in the bucket—quite literally! The bucket was nearly full to the brim with 250 beetles, and I eventually stopped counting. I’d estimate that I spotted nearly 400 stag beetles in a single night.
I did eventually confirm that the species of stag beetle in the lawn was Lucanus placidus. According to the scientific literature, aggregations have been noticed in lawns on occasion. In Kriska and Young’s “Annotated Checklist of Wisconsin Scarabaeoidea” (2002) an aggregation of 15 males and females was once noted beneath a black oak tree in the state. I’m not entirely sure what kind of tree used to occupy the low spot in my front lawn, but the stag beetles obviously loved it (note: stag beetle larvae live in decaying wood). As an interesting side note, the same low spot was also home to the “Dead Man’s Fingers” fungus (Xylaria polymorpha), another biological curiosity in its own right.
It’s amazing what you can find in your own back yard or front lawn if you take the time to look!
With mosquito season nearly upon us and all the headlines about Zika Virus in the news, a big question at the moment is: will Zika be an issue for us in Wisconsin? Based on what’s known about the Zika Virus and the mosquitoes that transmit it, it’s unlikely that Zika will be a major issue for us in the state. Certainly, we’ll get cases of Zika in the state, but these will almost certainly be from individuals that have travelled to areas with active Zika infestations. Overall, if we look at the bigger picture, a much bigger concern should be deer ticks and Lyme Disease, which affects thousands of Wisconsinites each year.
The Zika situation is an interesting one. The Zika virus itself was first discovered in Africa in the 1940’s and has been found in parts of the eastern hemisphere for decades. It wasn’t until very recently that it popped up the western hemisphere. Because the Zika Virus is linked to a number of serious health issues, such as microcephaly in newborns, it certainly can pose significant health risks—hence the headlines and the concern.
However, the virus is only half of the story—the other half being the mosquito species (vectors) capable of transmitting the virus to humans. Two mosquito species are associated with Zika virus and other viral diseases such as Chikungunya and Dengue: the Yellow Fever Mosquito (Aedes aegypti) and the Asian Tiger Mosquito (Aedes albopictus). The good news for us in Wisconsin is that neither of these mosquito species are native to our area, and these species have never been found in the state (additionalsurveys are being conducted to look for them). With that said, there may end up being some Zika cases in Wisconsin associated with travel to areas where Zika is widespread, but the absence of the two mosquito vectors responsible for transmission will greatly reduce the chance for transmission occurring within the state.
While the Yellow Fever Mosquito and the Asian Tiger Mosquito don’t occur here, there still is reason to be vigilant about mosquitoes. With as many as 60 or more different mosquito species in the state, there are a number of other mosquito-borne diseases that do occur in our area. Our best example would be West Nile Virus transmitted by the Northern House Mosquito (Culex pipiens). While West Nile cases can vary dramatically from year-to-year, we’ve historically had issues with West Nile in our area, and human deaths have occurred in the past.
When it comes to mosquitoes in general, there are several approaches to keeping yourself and your family members safe. Around the yard, one of the most important things is to reduce or eliminate standing water to help eliminate mosquito breeding sites. Toys left out in a sandbox, old tires, clogged gutters, birdbaths with stagnant water and anything else that collects and holds water could be a potential breeding site for mosquitoes. Using EPA approved repellents, such as DEET, Picaridin, or others when working or relaxing outdoors will offer protection from bites. Lastly, wearing long sleeves, avoiding outdoor activities during prime mosquito feeding times (dawn/dusk), or simply staying indoors can also protect you from mosquitoes.
While most of the cases at the Insect Diagnostic Lab involve fairly common insects, I do also see my fair share of unusual cases each year. One of my favorites from 2015 involved a miniature “bog wasp” from the family Eucharitidae: Pseudochalcura gibbosa. Due to their small size, these tiny (~2 mm long) wasps would simply go unnoticed in most cases––that and the fact that you’d most likely have to be wandering around in a bog to find them. So how exactly did these tiny, easily-overlooked “bog wasps” end up being submitted to the Insect Diagnostic Lab? Simple: a homeowner found several in a second story bedroom of their house. This simply didn’t make much sense, so I knew there must have been a deeper story at play. Whenever I get an unusual case like this in the diagnostic lab, I often have to track down additional pieces of the puzzle before things make sense.
In this case, this particular home was located near Rhinelander, Wisconsin, where there’s certainly an abundance of bogs. As part of their life cycle, the females of Pseudochalcura gibbosa lay eggs on Bog Labrador Tea (Ledum groenlandicum), a common shrubby plant in northern bogs. The eggs spend the winter on the plants and hatch the following spring. However, these wasps aren’t plant feeders, and their presence on Labrador Tea is temporary. What they’re really after are immature carpenter ants (Camponotus sp.) to feed on. After the eggs of Pseudochalcura gibbosa hatch, it’s thought that the wasp larvae hitch a ride on foraging carpenter ant workers back to their nest. Once they’ve dropped off their six-legged taxis in the ant nest, the tiny larvae of Pseudochalcura gibbosa behave much like a wood tick on a dog: they hang off of and feed on carpenter ant larvae and pupae. In some cases, dozens of small wasp larvae may be present on a single carpenter ant larva. Eventually the tiny wasps complete their development and leave the carpenter ant nest to head back to the bog.
Having identified the wasps as Pseudochalcura gibbosa, I was suspicious that a carpenter ant nest was also present in the home and simply hadn’t been found yet. After some detective work, the homeowner eventually confirmed the presence of carpenter ants in the house. With that final piece of the puzzle I had my explanation for how the wasps had hitchhiked from a nearby bog to an upper story bedroom: it’s was all the ants!
In this post, we’re continuing to count-down 2015’s top insect trends in the state. This is the final post in a three part series. Part I (2015’s diagnostic lab statistics) can be found here and Part II (Top Insect Trends Numbers 10-6) can be found here.
With all the headlines about bees, it’s not surprising to see pollinators in the top insect stories again in 2015. Similar to other years in the recent past, honeybees and other pollinators have been facing declines. Unfortunately, Wisconsin saw some of the highest honeybee losses in the country, with over 60% colony loss during the 2014-2015 period. Some good news over the past year has been the development and release of pollinator protection plans. A federal pollinator protection plan was released in May with the goals of reducing honeybee losses, increasing the population of Monarch butterflies, and increasing pollinator habitat. In addition, a Wisconsin pollinator protection plan was announced in 2015, and was just released in January of 2016. Due to the recent declines and their importance to agriculture in the state and nation, pollinators will continue to be in the spotlight in the future.
4) Spring caterpillars
An unexpected insect trend in the spring of 2015 was the surprising abundance of a number of caterpillar species feeding on plants in the landscape. Caterpillar species, such as the humped green fruitworm, speckled green fruitworm, eastern tent caterpillar, forest tent caterpillar, gypsy moth caterpillar, and the euonymous caterpillar are typically present to some extent, although their numbers have been low the past few years. For a number of potential reasons, these species had a great spring and during a period in May and June, caterpillars made up roughly 30% of the cases coming in to the diagnostic lab. Weather patterns (i.e., rainy weather) and natural predators/parasites/diseases can have significant impacts on caterpillar populations each year, so it’ll be interesting to see if we’re faced with a plethora of caterpillars again in 2016. Additional details of this story were featured in a blog post last June.
3) Viburnum Leaf Beetle
In terms of a new emerging pest with the potential to impact a commonly planted landscape shrub, Viburnum Leaf Beetle is near the top of the list. As of late 2014, we only knew of a single infested viburnum bush in northern Milwaukee County, which raised the question: is the infestation small enough to contain and/or eradicate? Some ground truthing this past spring identified many new infestations in SE Wisconsin, in many cases miles from the original site. At the moment, the viburnum leaf beetle seems to be centered around the four county area where Milwaukee, Waukesha, Washington, and Ozaukee counties meet. While this insect only feeds on viburnums (and related plants like Arrowwood), the damage can be significant. It may be some time before this pest spreads elsewhere in the state, but if you have viburnum plants in your yard in SE Wisconsin, be weary! Additional details of this case were featured in a post last June.
2) Brown Marmorated Stink Bug
Populations of the invasive Brown Marmorated Stink Bug increased dramatically in 2015 and this insect takes the overall #2 spot in this list (up from #8 last year). This invasive species was first spotted in the state in 2010, and each year a handful of lone adults have been found in Wisconsin. In the fall of 2015, we had more sightings of BMSB (30+), than in the past 5 years combined! (Spoiler: this trend has continued into early 2016) At this point, the “hot spots” in the state are: Dane County, the greater Milwaukee area, and the Fox River Valley. In addition to being an indoor nuisance pest, BMSB can also feed on and damage a wide variety of plants in home gardens, agricultural fields and orchards. In other places in the country, the first reports of plant damage have typically been noted ~3-5 years after the initial detection of this species. With that said, 2016 could be the year that BMSB really takes off and starts wreaking havoc for gardeners and agricultural growers alike. Additional details of this case can be found in this post from last October.
1) Magnolia Scale
While scale insects have already been mentioned in the “sucking insects” section (#9 on the list), one species in particular, the Magnolia scale (Neolecanium cornuparvum), seemed to stand out amongst all other insects in 2015. This species is often present in low numbers in the state, but the conditions must have been perfect for their populations to explode last year. During the months of June and July, reports of Magnolia scale were coming in on almost a daily basis. Being one of the unusual scale insects, Magnolia scale adults look more like a fungus than an insect (note the whitish blobs in the image below). Not only did this bizarre looking species pummel Magnolia shrubs and trees in many parts of the state, but the honeydew produced by these insects rained down below, attracting ants and yellowjackets and leading to the growth of unsightly black sooty mold. A number of predators, parasites, and diseases typically keep Magnolia scale in check, but with the extremely high infestations noted last year, it’s likely that we’ll continue to see some Magnolia scale activity into 2016. If you experienced magnolia scales first hand, there’s a helpful factsheet available here.
What were Wisconsin’s top insect trends of 2015? In this post, we’ll look at the first half of our count-down.
This is the second post in a three part series. The first post of the series (2015’s diagnostic lab statistics) can be found here.
10) Mosquitoes and ticks:
Like most years, Wisconsin had a pretty good mosquito season. Overall, we were close to the average rainfall mark during much of the year, which meant the typical batch of mosquitoes starting after Memorial Day. In many parts of the state, mosquitoes were prevalent throughout June, July, and August. However, this is Wisconsin after all, and mosquitoes seem to be one pillar of summer culture along with beer, cookouts, and fishing. The silver lining of the mosquito story is the fact that West Nile Cases were low for the year, with only four confirmed human cases reported in the state in 2015.
While there wasn’t anything out of the ordinary with the mosquitoes last year, ticks seemed to have a particularly good year in the state. Deer ticks, which can vector Lyme disease can be found essentially statewide. From the standpoint of an emerging health threat, deer tick populations have exploded in the past few decades (our first deer tick wasn’t found in the state until the 1960’s). A recent nation-wide study found that deer ticks were found in nearly half of the counties in the U.S. One of the more alarming trends is urban encroachment. Historically, ticks seemed to be the type of creature you’d pick up if you were out hunting or hiking through the woods. In the recent past, we’ve noticed an increase of ticks found in more urban environments, such as parks and backyards. With roughly 40% of the adult ticks in Wisconsin carrying the microorganism responsible for Lyme Disease, this is an issue that will continue to exist in the state for years to come.
9) “Sucking Insects”
A certain group of insects (the Order Hemiptera) are sometimes known as the “sucking insects” because they possess tube-like mouthparts which are used by many species use to drink fluids from plants. Two of the members of this group, the aphids and the scale insects had a great year in 2015. When these insects feed on plants, a common sign is the presence of sticky, sugary honeydew, which attracts ants and yellowjackets, and can result in the growth of black sooty mold. Aphids and scale insects are common and typically present in low numbers, but the conditions must have been just right for their populations to thrive in 2015. As a result, there were many reports throughout the state of honeydew “raining” down from trees and shrubs onto vehicles, decks, outdoor furniture, and people below. If you felt “rain” on a sunny day last summer, the actual cause may have been honeydew dripping down from aphids or scales in the trees above!
8) Long Lost Pests: Japanese Beetle and Gypsy Moth
Two of our best-known landscape pests, the Japanese Beetle and the Gypsy Moth had been very quiet in 2014, but resurfaced last year. Japanese beetles had been low across the state in 2014, likely due to the brutal winter of 2013-14 killing many of the soil-dwelling grubs. While we did see an increase in beetle activity in 2015 compared to 2014, their numbers still seemed low compared to the long term average. However, with a milder el Niño winter, it’s possible that we could see increased winter survival and higher Japanese beetle populations in 2016.
Gypsy Moth populations have been low the past few years in Wisconsin. Damp spring conditions can result in a fungal disease killing many of the caterpillars, which likely helped lessen populations in the recent past. It’s also not unusual for some long-term cyclic patterns to be involved with insect populations. For a number of potential reasons, Gypsy Moth populations seemed to rebound a bit in 2015, and many reports of sightings and damage came in to the diagnostic lab, particularly from the south central portion of the state (Dane, Rock, Walworth Counties). Because Gypsy Moth can be a destructive defoliator of hardwood trees, it’ll be good to keep an eye out for this one in 2016 to see if the populations continue to climb.
7) Emerald Ash Borer
This is our most destructive forest pest in the state, and unfortunately, there doesn’t seem to be anything capable of completely stopping this pest. While we didn’t see many additional counties added to the quarantine map in 2015, there were many municipalities that detected EAB for the first time. At the moment, 39 of the 72 Wisconsin counties are quarantined for EAB and this number will continue to increase over time. Like Dutch Elm Disease in the past, Emerald Ash Borer is changing and will continue to change the appearance of our urban forests and woodlands for years to come.
6) Spotted Wing Drosophila
This invasive pest first showed up in the state in 2010, and became a significant fruit pest almost immediately. Since its introduction, SWD has spread widely and can be found in most counties in Wisconsin. Very similar to 2014, SWD was detected in dozens of counties across the state. SWD can attack a wide variety of fruit, but due to the fact that this insect doesn’t seem to become active until July, the late-season raspberry and blackberry crops are hit the hardest. Luckily Wisconsin’s famous cranberry crop does not seem to be favored by this invasive pest.
What’s been “crawling” in the UW-Madison Insect Diagnostic Lab this past year? Find out in this three part series.
The State of the IDL in 2015
While it wasn’t exceptionally “buggy” in Wisconsin this past year, 2015 ended up seeing the highest annual caseload ever handled by the UW-Madison Insect Diagnostic Lab. The previous annual caseload record belonged to 2013, with 2,207 specimens. In 2015, the lab identified a whopping 2,423 specimens from 71 of the 72 Wisconsin counties. The vast majority of cases, (>94%; 2,287 specimens) originated from within the state of Wisconsin, 93 samples (digital images) came from other U.S. states, and 43 international samples (digital images) were handled by the IDL in 2015*. As expected, the bulk of the submissions came during the warmer months when insects are most active as illustrated below:
Overall, roughly half of the samples processed by the lab in 2015 consisted of digital images, which is similar to other recent years; the remainder of the cases involved physical specimens or verbal descriptions of the insects. Approximately half of the processed samples were submitted by the general public, over a quarter came from UW-Extension county agents/support staff, and smaller quantities came in from pest control professionals, agricultural producers and consultants, members of the green industry (lawn care, arborists, nursery), medical and public health professionals, and colleagues in academia and government agencies such as the Wisconsin Department of Natural Resources and Wisconsin Department of Agriculture Trade and Consumer Protection.
In 2015, the Insect Diagnostic Lab’s database was upgraded to include real-time statistics on the identity of specimens submitted to the lab. Overall, >80% of the samples handled by the lab were Hexapods (insects and close relatives, such as springtails), >10% were arachnids (spiders, mites, ticks) and myriapods (centipedes and millipedes), and the remainder of the cases involved other animals (slugs, crustaceans, vertebrates, etc.) or other factors (plant disease, physiological plant stress, and non-living or unidentifiable specimens). Of the insect specimens processed in 2015, 21 different major insect groups (orders) were represented as shown in the chart below. Of these groups, 5 orders in particular made up 92% of the specimens handled by the IDL last year:
Coleoptera: beetles, such as Japanese beetles and carpet beetles
Hemiptera: “true Bugs”, such as aphids, and boxelder bugs
Lepidoptera: moths, butterflies, and their young (caterpillars)
Diptera: “true flies”, such as house flies and mosquitoes
Interestingly, submissions can vary quite a bit throughout the year as illustrated by the prevalence of caterpillars seen this past spring as described in an earlier blog post.
Other Lab Activities
In addition to providing diagnostic services and pest management advice, another major function of the Insect Diagnostic Lab is to provide insect-related outreach for UW-Extension and the UW-Madison Entomology Department. To that end, IDL staff delivered 105 presentations at workshops, field days, seminar series, and other events and participated in dozens of Extension and outreach events throughout Wisconsin in 2015 (State Fair, Garden Expo, summer children’s programs, etc.). IDL staff also conducted 36 radio, TV, and newspaper interviews in 2015, including 7 (1.5 hour) episodes on Wisconsin Public Radio’s “The Larry Meiller Show”. Eight Extension factsheets and other publications were authored or co-authored by IDL staff in 2015 and the Insect Diagnostic Lab and associated “Insect ID” website were viewed over 400,000 times in 2015.
* In case you’re curious, international cases in 2015 came from 11 different countries on four continents: Mexico, Costa Rica, the United Kingdom, Italy, Greece, Nigeria, Zambia, India, Bhutan, the Philippines, and Japan.