The Buzz About Paper Wasps

Common paper wasp (Polistes spp.)
Photo:  Russ Ottens, Univ. of Georgia

The cooling weather will soon bring an end to activity for Polistes or paper wasp colonies. There are

several species of paper wasps, but the common ones are brown in color with yellow stripes on their abdomens. The workers (who will die soon), along with next year's crop of queens, are starting to bail out of their nests. The surviving queens will seek out some place to pass the winter. All too often our houses, and other structures, become the location of choice.

You may begin seeing wasps outdoors hovering about the eaves and soffits on warm afternoons. At some point, the wasps may make their way indoors, and things can get more exciting. The wasps are often seeing moving about slowly and bouncing off windows, ceilings, light fixtures, etc. Cold weather seems to stop the activity, but quite likely on subsequent warm days you will find wasps flying about indoors or again spot them outside around the roof area.

A few things to keep in mind:

First - seeing the wasps does not mean that there is a nest in a wall; however, there may be a nest outdoors on a roof overhang, under a porch, in/on a tree or some other protected area.

Second - since these are queens looking for overwintering sites and not workers defending a nest, they are not aggressive and so stinging incidents are rare unless you have a "close encounter of the Polistes kind," such as I had when I laced up my running shoe one morning only to discover that a wasp had crawled inside there during the night.

Third - spraying indoors is an exercise in futility because there simply isn't a specific target area you can treat. Spraying the exterior of the building also has limited value because there are so many gaps accessible to the wasps.

Best advice: keep a rolled-up newspaper handy. Be patient; let the wasp land then smack it.

For further information about paper wasps, check out:

http://www.ces.ncsu.edu/depts/ent/notes/Other/note144/note144.html

http://insects.ncsu.edu/Urban/paperwasp.htm

Kudzu Bugs on the Move Again

Kudzu bugs aggregating on structure searching for 

overwintering sites (Photo:  Dan Suiter, Univ. of Georgia)

Kudzu bugs will soon be moving out of soybean fields, which means you may begin seeing them aggregating on or inside structures. The kudzu bug's fall movement indoors is very similar to what we've experienced since the 1990’s with the Asian lady beetle. The major difference between the two insects is that the Asian lady beetle is actually beneficial as a biological control agent because it feeds on aphids and other plant-feeding insects. By contrast, the kudzu bug's primary food source (aside from kudzu) happens to be field crops, such as soybeans, where they can significantly impact on yield. The kudzu bugs fondness for soybeans is one reason why we could see significant numbers of them invading homes and other buildings, even in rural areas. In more urban areas, there are plenty of other hosts, such as wisteria and privet. The insects are quite mobile; they are able to catch rides on wind currents, as well as automobiles, trucks, trains, and planes. This helps explain why this pest has managed to spread in about 4 years from the north-central Georgia to most of South Carolina, North Carolina and on into Virginia (plus west into Mississippi).

At this point, we still do not have anything new to report in terms of recommendations as to how to address this problem. Kudzu bugs are attracted to light-colored surfaces but that certainly doesn't mean that brick buildings or those with dark-colored siding will escape the bug invasion. While shortcuts and easy solutions would be nice, there simply aren't any.

The emphasis still has to be on exclusion because chemical control is only partially effective and relies primarily on targeting the insects that are aggregating on surfaces. Preventive sprays are not recommended because they simply won't be durable enough to last the weeks during which these insects will be actively seeking overwintering sites. If you feel a treatment is required, stick with targeted treatments of critical areas: windows and doorframes, soffits, and eaves. If you choose to treat using a pyrethroid insecticide, remember to follow new label requirements. For the latest label changes, visit:  http://www.epa.gov/oppsrrd1/reevaluation/environmental-hazard-statment.html.

For more information about the kudzu bug, please visit our website: http://www.ces.ncsu.edu/depts/ent/notes/Urban/kudzubug.htm

Spring Insect Invaders

Paper Wasps. Paper wasps (Polistes sp.) are long-legged, reddish brown to black insects with slender spindle-shaped abdomens. They may have differing degrees of yellowish or brown striping. Paper wasps can become a problem in the fall as the inseminated queens invade homes in search of overwintering sites. But paper wasps can also become a problem in the spring. As temperatures begin to climb, queens that spent the winter in structures become active and fly about. If they have been resting in an attic, wall void or crawlspace, the wasps may be attracted to light coming through a gap in the baseboard or a wall fixture, or around an AC vent and emerge inside the building. Since there are no nests or young to defend, the only real danger of being stung is from accidentally stepping on or pressing against one.

Figure 1. Use an aerosol insecticide
to destroy a paper wasp nest
(Photo: Patty Alder)

Control. Queens that are found indoors may simply be swatted or vacuumed. If a queen does manage to get outdoors and start a nest, a broom may be all that is needed to knock it down. If a wasp nest has had some time to grow and is considered to be a hazard, they are most easily destroyed in the evening with an aerosol insecticide that is labeled for "hornets or wasps" (see Figure 1). 

Clover Mites. Clover mites are occasional invaders that can become a problem in early spring. They are tiny (1/30-inch long), red to reddish-brown, oval-shaped mites. Clover mites, as do other arachnids, have 8 legs. They hold the front pair of legs straight out in front of the head. Many people actually mistake this pair of legs for antennae. Clover mites do not bite nor do they burrow under the skin. They are strictly plant feeders. Hosts include grasses, clover, and dandelion, to name a few.

Most heavy outbreaks occur in the early spring, especially around heavily fertilized lawns. The mites may invade homes and can leave a reddish-brown stain if crushed.

Control. An 18”-24” grass and weed-free zone around the structure’s perimeter can greatly reduce the number of invading clover mites (Figure 2). In addition, treating a 5-10 foot wide area of ground along the foundation, as well as an 18-24 inch wide vertical band of the foundation wall with an appropriately labeled residual liquid insecticide can help.

Figure 2. Placing gravel around the structure
can help prevent clover mite invasions
(Photo: Mike Waldvogel)

 Many plants are actually unattractive to clover mites, including geranium, marigold, zinnia, salvia, rose, chrysanthemum petunia, juniper, spruce, yew and barberry. Planting these non-attractive plants in the weed-free zone will help reduce the number of clover mites around the structure. You may also contact their county Cooperative Extension Center for advice on proper fertilization of your lawn.

The application of insecticides indoors for clover mites is not warranted. Simply use a vacuum cleaner to collect any mites found indoors. Care should be taken not to crush the mites. The vacuum bag should be sealed in a disposable plastic bag before throwing it away.

Kudzu and Brown Marmorated Sting Bugs. We will most likely start to see an increase in the activity of kudzu bugs and brown marmorated stink bugs as well. The stink bugs have a broad host range and are often found on Paulownia (empress tree), Ailanthus (tree of heaven), and crabapple among others, but at this point in the year (particularly in western NC) those host plants have little foliage and cooler weather has kept the bug activity down. And so, a lot of this current activity is simply a response to the warmer temperature and you'll see the insects on non-host sites, such as house siding, cars, etc. Kudzu bugs will be aggregating on almost anything and so you will see them on wisteria and other plants (even if there isn't much foliage), houses, early-planted beans in people's gardens, etc. But even on plants with foliage the insects will simply be hanging out rather than feeding.

Control. Treating the exterior of buildings with a spray insecticide using products containing pyrethroids (such as bifenthrin) may provide termporary relief, but don’t expect any long term relief. There's a big difference between "killing" individual bugs and "controlling" a population of them when these bugs are essentially a "moving target" in terms of where and when they'll show up. In spring, the situation is different than it is in the fall. In the fall, these insects are searching for a way to get into buildings in order to survive the winter. Now, their attention is focused on heading to the great outdoors in search of food and potential mates. So, spraying aggregations (e.g., clusters on a wisteria plant) will kill a bunch of bugs, but more are likely to show up later.

We have information for residential settings at:

http://insects.ncsu.edu/Urban/kudzubug.htm

Figure 3. Boxelder bug adults and nymphs
(Photo: Whitney Cranshaw)

Boxelder Bugs. Adult boxelder bugs are about 1/2-inch long, black with orange or red markings, including three stripes on the area right behind the head. Their wings lay flat over their bodies, overlapping each other to form an ‘X’ (Figure 3). The immature nymphs are 1/16th-inch long and bright red when they first hatch. As they grow and become larger, they become red and black. You can potentially see all stages at any given time during the summer.

Adult boxelder bugs emerge from their overwintering sites in March and early April and feed for about 2 weeks before mating. These insects prefer sunny areas and, therefore, are found most abundantly on trees in a southern exposure and on sides of buildings facing south. The boxelder bug population increases rapidly from middle July to early September.

Boxelder bugs have unusual feeding preferences. Because these insects feed primarily on boxelder and maple seeds, the insects are found on the ground beneath female trees in the early summer before the seeds start to develop. The bugs move into the trees once seeds begin to form. These insects are cannibalistic, particularly when the victim is molting, and they have been reported to feed on other dead or dying insects.

Control. The most permanent solution to a boxelder bug problem is the removal of female boxelder trees from an area, although in most cases this will not be practical or desirable. Outdoors, a pesticide application around the exterior of structures may help reduce the number of invading boxelder bugs. Preventing boxelder bugs from getting into the structure is key. Caulk or otherwise seal any openings the bugs may be using to get indoors. Bugs that enter the home may simply be vacuumed up.

Insect of the Week - The Camel Cricket

Camel cricket
(Photo: David Cappaert, Michigan State University)

Camel crickets are one of those insects that are just so icky to me! The crickets are so-named because of their slightly hump-backed appearance. Adults are 1"-1.5" long. Their long legs give them a creepy, spider-like appearance. Interestingly, camel crickets do not "sing" or "chirp" like most other crickets do. And unlike other crickets, camel crickets do not have wings as adults.

Camel crickets are usually associated with cool, damp, dark places. Outdoors, they can be found under stones and logs, in stacks of firewood or other debris, or in leaf litter. Areas that are overgrown with thick vegetation, such as ivy and other ground cover provide excellent hiding places. Camel crickets often inhabit moist, humid areas in and around our home, such as crawlspaces, basements, garages, and other indoor areas where moisture may be a problem. A telltale sign of a heavy infestation is the presence of dark fecal smears on surfaces (such as on the floor joist in the picture below).

Like other crickets, camel crickets will invade buildings in the fall seeking suitable places to pass the winter. In these cases, they often remain in basements or crawlspaces and seldom damage items in the home. Although they are mostly a nuisance pest, camel crickets can damage stored items, such as garments and linens packed in boxes in a garage or basement, if the problem goes unchecked for some time and the crickets cannot find suitable food.

Controlling camel crickets.
Because moisture is such an important requirement for camel cricket survival, reducing the number of moist habitats is essential for good, long-term control. Doing what you can to prevent crickets from entering the structure is also important. Following a few simple steps can accomplish both strategies and will go a long way in effectively controlling these crickets.

• Keep weeds and tall grass next to the building mowed.
• If possible, keep mulch, thick ground covers, and shrubs away from the foundation wall.
• Store lumber, fire wood, and other wood piles away from the foundation.
• Make sure windows have screens that fit properly and are not torn.
• Install weather-stripping around all doors and windows.
• Seal small openings on the outside of the home with caulk.
• Install screen on crawlspace and dryer vents.
• Make sure crawlspaces and basements are properly ventilated to reduce moisture.
• Any boxes stored in basements or garages should be stacked away from the wall. If possible, stack the boxes on pallets.
• Camel crickets that make their way inside can be vacuumed up, squashed (yuck), or placed outdoors.
• If you have a cat or dog, they may take care of the camel cricket for you; mine always do!

Sugarcane Beetles

Adult sugarcane beetle (Photo: Cotinis, BugGuide.net)

We are getting reports of sugarcane beetles (Euetheola humilis) showing up in large numbers in areas of North Carolina, South Carolina, and Tennessee. The adults are dark brown, about 1/2" in length, and somewhat resemble the May and June beetles you likely saw on your porch back in May-July. The sugaracane beetle has become a more significant pest of turf in recent years, particularly (but not solely) in warm-season grasses like bermudagrass. While most of you may not worry about turf (except for perhaps your own lawns), adult beetles are strongly attracted to light, which means structures near well-lit turf (schools, commercial buildings, etc.) often get hit the hardest. Sugarcane beetles may also begin invading homes and other structures as they search for a suitable overwintering site. The beetles are common insects, but their populations are usually so low that they go largely unnoticed.

One oddity about sugarcane beetles is their tendency to chew/bore into expansion joint material along the front of commercial or industrial buildings, and we've heard of some instances where they reportedly chewed through insulation, caulk, and membrane roofing material. In the case of expansion joints, the beetles may be looking for moist areas to deposit their eggs. The organic debris that can build up in expansion joints may serve as a food source for larvae.

Sugarcane beetles gathering around expansion joint (Photo: Chris Mills)

Exterior treatments will likely kill off a lot of beetles. Just make sure your customer understands that they will quite likely see other beetles which are drawn to exterior lighting (and to nearby grassy areas). Any beetles that make it inside structures should simply be removed or vacuumed up. Interior spraying isn't necessary for sugarcane beetles. Since the beetles are attracted to light, using sodium vapor lights in fixtures near buildings and mercury vapor lights for fixtures away from buildings may reduce the number of invading beetles; however, this is not always practical.