Pestworld Magazine Focusing on the Business of Pest Management
ANTS
I’ve read that pavement ants have a stinger, but I’ve never been stung by one. Can they sting and should my customer’s be concerned about it?
It’s true, pavement ants (Tetramorium caespitum) have a stinger, but they rarely use it. Found throughout most of the United States, the pavement ant is one of the most common nuisance ant species in the Northeast and Midwest. Winged reproductive ants are often seen during their mating flights in the spring and are sometimes confused with termites by consumers. Pavement ants often nest under slabs, patios or landscaping features. Pavement ant stingers are so small that they generally cannot penetrate human skin and are not considered a threat to human health, so your customers don’t need to worry about getting stung by these pests.
I recently found velvet ant in my customer’s yard while performing a perimeter pest control inspection, how can I manage them for my customer?
Contrary to their name, velvet ants aren’t actually ants at all. They belong to the family Mutildae (ants are in the family Formicidae). Mutilids are a family of solitary wasps. The females, which are what you mostly observed, are wingless and almost always hairy and brightly colored. Velvet ants may be found with bright red, purple or orange and black markings. Like many other venomous animals, the bright coloration is a warning to stay away; the females have an extremely painful sting, earning them the nickname “cow killers”. Males have wings but are stingless and rarely encountered.
Velvet ants are parasites of other insects, most commonly ground nesting bees and wasps like bumble bees and cicada killer wasps. The females locate the nest of the host (sometimes through use of force) and lay eggs in the brood chamber. When the larvae hatch, they consume the eggs and larvae of the host. Adult velvet ants typically feed on nectar.
Velvet ants aren’t pests, but since they can deliver an extremely painful sting, you should encourage your client to make the yard less inviting to the host species that females are searching for. Bare patches in grass are often an inviting place for cicada killers, so they should be repaired, especially if cicada killers have been sighted in the past. Luckily, unlike hornets, and yellow jackets, velvet ants are not social insects, so there is no nest to be concerned about and typically the sightings are few and far between.
BEDBUGS
Late last fall I was treating a house for bed bugs and after 3 visits, I eliminated the infestation (to the best of my knowledge). Fast-forward to March and that same house has a new (or recurring) infestation. The thing is, this is a three-story house in Ohio with a finished attic and the recurrence is in an attic bedroom. I checked out several of the bugs under a microscope and realized they are actually bat bugs! I never thought to check originally because the initial infestation was huge and the bugs were only found on the first floor. What’s going on here and how do I proceed?
It is certainly possible that this house experienced a one-two punch of bed bugs and bat bugs. The odds of this happening are very slim, but similar occurrences have been documented and there isn’t anything about the presence of one species or the other that would preclude the other from being in the same structure. The timeline for the initial infestation could coincide with bats leaving a roost in the structure to seek out their hibernacula. Conversely, the fact that the initial infestation was large and exclusive to the first floor casts doubt on that notion.
Since it’s too late to be 100% positive that the initial infestation was bed bugs, we can only focus on the current problem. The body of knowledge about bat bugs (and swallow bugs) is poorly developed at this point but the first step should be to determine if there is currently a bat problem in the house. Check for possible bat entry/exit points under the eaves, around the chimney, beneath the ridge cap, and anywhere else in the vicinity of the infested bedroom. Bat bugs will feed on people but we are certainly not their preference, so if bats are (safely, of course) evicted the infestation most likely won’t be sustained. Once the bats have been evicted, start your control and monitoring efforts on the recently vacated roosting spot(s) and focus on other voids, cracks and crevices, and areas in which you are finding evidence of bat bugs.
One final note, although I understand why you assumed bed bugs given the nature of the initial infestation, remember that it’s always recommended to get a positive ID before proceeding (and it doesn’t hurt to save a few specimens just in case).
I’ve been told that bed bug nymphs can survive without a blood meal by eating bits of dried skin particles found on mattresses, is this true?
Bed bugs (Cimex lectularius) have mouthparts that are modified for eating one thing – blood. Bed bugs are considered true bugs which all have gradual metamorphosis, meaning that the immature stages look like, and exhibit the same feeding preferences and habitat as adults. Both nymphs and adult bed bugs feed exclusively on blood. In fact, a blood meal is required for nymphs to develop from one nymphal instar to the next. In addition, blood meals are required by adult females to produce eggs.
Your source may have been confusing the nutritional preferences of bed bugs with house dust mites (Dermataphagoides spp), which do not feed on human blood, but consume shed human and animal dander (skin particles), mold spores, pollen grains and feathers. High populations of these tiny (0.33 mm) mites are often present in mattresses and furniture. Even though house dust mites do not bite, they are considered one of the top causes of allergic reactions and are considered a major factor for most asthmatics.
Our company just invested in a bed bug detection dog. How do I get our canine certified?
Scent detection canine certification testing can be performed by an organized body or an individual evaluator. When choosing who will perform the certification testing and provide the credential for your canine team, there are many factors to consider, not the least of which are the qualifications of the evaluators and the testing protocols and procedures employed. Check to make sure that the evaluator meets the qualifications set forth in the NPMA Best Management Practices for Bed Bugs (BMPs) and the certification test meets the minimum standards outlined in the BMPs.
A common misconception is the idea that a canine can be individually certified. The BMPs note that only canine teams (the handler and the canine) can be certified. Without human handlers interpreting the behavioral changes in their canine counterparts, canines have little value as bed bug detectors. If multiple handlers are assigned to perform inspections with a single canine, each combination of canine and handler must be tested individually. If a single handler works with multiple canines, the same rule applies. The reason for this requirement is that each canine has unique, often subtle, behavioral cues that indicate that it has detected a target odor, so handlers need to be trained and tested for work with each canine. In the same way that the BMPs do not provide for certification of individual handlers or canines, individual companies are not able to be certified either.
BEES AND WASPS
I service a doctor’s office that is in a commercial building. Over the past 2-3 years I have found European hornets nesting in the mulch near the entrance to the office. I had little difficulty finding and treating nests and both the client and I were happy with the results after treatment. However, this year the hornets are back and I can’t find any nesting sites for the life of me. I have canvassed the surrounding area without any signs of nesting and have been unable to track any of the many hornets flying around the building. Any ideas?
The good news is that European hornets are not aggressive and are (in most settings) beneficial due to their habit of preying on grasshoppers, flies, and other miscellaneous insects. As you are well aware, the benefits of European hornets are not enough to overwhelm the face that large, stinging insects are not welcome in a place where people in various states of health are frequenting. For a large number of these hornets to be present during the day time suggests that the nesting site is not far away. Have you thoroughly investigated the building itself?
These hornets will nest in structural voids and their entrance may be inconspicuous. If you have a stethoscope or other listening device, give that a shot. Are there any trees in the vicinity with branches and leaves that would obscure views of a nest?
If you haven’t already, I recommend visiting the site at night to see if you can better observe their movements and track down the nest(s). Focus your efforts on trees and perimeter walls and make sure to use a yellow filter on your flashlight so you don’t attract bees to your person. If nest locating efforts continue to be fruitless, you can move on to secondary control strategies like treating for their food source and removing fallen fruit and other attractive organic matter.
I recently found dozens of tiny (what I believe to be) wasps in an interior wall near a window in a residence. What could these be and why did so many of them appear at once when I’ve never encountered them before?
While ID is necessary to answer your question completely, the most likely explanation is that you stumbled across a bunch of parasitoid wasps. Parasitoids develop inside of, and eventually kill their host. Many wasp species fit the description of being a parasitoid, and all sorts of different organisms, like beetles, butterflies and moths, Hemipterans (true bugs), and even spiders, are used as hosts. The female wasp oviposits into the egg or body of the host and the larvae develop inside the host until pupation, at which point the host is dead or close to it. Parasitoids are very specific in their host preference, which makes them great candidates for use in biological control.
There is/was some host species present in the structure that yielded all the wasps you found. Unfortunately, identification of parasitoid wasps can be quite challenging, both due to their small stature and incredible species richness of the group. Your best bet is to monitor throughout the structure for whatever the host might be, as the wasps you found were likely drawn to that area because of the light coming from the window.
BEETLES
I keep finding drugstore beetles in the light traps placed high above the floor in a food processing plant. The plant makes dried treats for pets. Can you explain this beetle and can you think of a source?
The Drugstore beetle, Stegobium paniceum (Linnaeus), most likely was named as such because it was commonly found infesting early pharmacies where dried herbs and other plants were used to compound medicines. Today, it is considered a stored product pest and, as you have noted, it can get into many areas since the adult does fly. You will find it in lights for two reasons. One possibility is that it was attracted to overhead lights or the light in the trap. The second reason is that the insect light trap tray might have a food source such as ingredient dust. These insects don’t feed on insects in the tray as readily as dermestids such as the warehouse beetle, but the tray can be attractive.
As far as sources, don’t expect that the beetles are infesting just the areas near the ceiling. In fact, that is probably not the case. Look for raw ingredient storage and seek out dried ingredients. Also, look for product spills and even food dust on the overhead areas. Don’t rule out minor ingredients such as spices. You can zoom in on an area by installing monitoring devices including pheromone traps. Then removal of the source can be done; if there is infestation on the outside of packaging but not inside, you can heat the material to at least 140° F for several hours. Don’t forget that animal food facilities must be maintained in the same fashion as plants that make human food, so any infestation must be addressed quickly.
I keep finding carpet adult carpet beetles near the windows at my client’s home. She has no carpets in the house, mostly hardwood and tile floors throughout their home with area rugs in some rooms, but I can’t find any signs of damage. Where they coming from and what are are they feeding on?
With the advent of synthetic carpet fibers, carpet beetles are rarely found feeding on carpets in modern homes. The preferred food sources for carpet beetles are natural animal fibers like wool. When carpet beetles earned their common name, many rugs and carpets were woven from wool, where the beetles were often found feeding on and damaging the fibers. With the exception of antique or specialty rugs, natural animal fibers are rarely encountered today.
Carpet beetles, which are members of the family Dermestidae, will feed on other animal products in structures, which is probably what’s going on in your case. Check the property for hunting trophies or animal hides, which may harbor an infestation. In pet supply stores, natural dog bones are often infested, so carefully inspect any treats that you bring home for your pets. Along those same lines, pet hair can also be a good food source carpet beetles. If your customer has pets, recommend that they perform a deep cleaning of the any areas where pet hair might have accumulated, like in the cracks and crevices around floor vents or baseboards. Finally, if the structure has a history of infestation by overwintering pests like, multi-colored Asian lady beetles, brown marmorated stink bugs, cluster flies or other pests, carpet beetles may be feeding on dead insects in the wall voids. It turns out that dead insects are a favorite food for carpet beetles, in fact, entomologists take care to keep them out of preserved insect collections where they can be extremely destructive.
I have a potential customer with a solid oak living room floor and it appears to have a powderpost beetle infestation. How can I tell if it is active and can I perform a topical treatment or do I have to ask them to strip the flooring?
It sounds like the floor has an infestation of Lyctid or Anobiid powderpost beetles. Lyctines prefer hardwoods while Anobiids will infest hardwoods or soft woods. The emergence holes look similar and if the frass and hole walls are light colored, that usually means that the wood particles have not oxidized into a darker color and thus would be considered fresh or active. You rarely see the actual insect. Pay careful attention, for if the holes appear to have any cross sections of galleries, that means that the damage was done by an insect prior to milling and then is not a concern. Some states do require determining if the infestation is active if this is a real estate transaction. If there is question or hesitance on the part of the homeowner, you can photo or mark the holes and return later in the season to see if there are new holes.
If you do decide to treat, most insecticides must penetrate the wood so the polyurethane must be removed for optimal effectiveness. Check the label and manufacturer’s information for more information on how to use specific products.
BUTTERFLIES AND MOTHS
We are observing small brownish moths in a client’s home, but we can’t determine where they are coming from. They are not Indian meal moths, at first we thought they were clothes moths, but we can’t find any damaged fabric.
The pest you are dealing with is the brown house moth, (Hofmannophila pseudospretella). It is not a very common pest, but can be a nuisance. This small moth ranges from 8.5mm (males) to 14.5mm (females) and has bronze colored wings covered with dark brown to black flecks. The reason that you are not seeing any damage in fabrics is that it might not be feeding on fabrics. The brown house moth has a wide range of foods that it will feed on including fabrics, seeds, processed grain, cereal, dead insects, dried flowers, furs and even dried bird or animal droppings. The omnivorous feeding habit of this species is one of the reasons that it is so successful.
Controlling the brown house moth is similar to the strategies that might be employed to control other stored product or fabric pests. Since we know what pest you are dealing with, the next step is to determine what it is feeding on. Identifying the brown house moth’s food source can be tricky because it feeds on so many different things and it might be feeding (and breeding) in multiple places at the same time. Start by checking the pantry for infested stored foods. Since you had already ruled out the possibility of the Indian meal moth, you might have skipped a thorough inspection of this area. In addition to cereals and processed grain products, inspect dried fruits and herbs for signs of moths or their larvae. The pupae of the brown house moth will incorporate bits of their food into their silken cocoon, but a careful inspection will reveal their presence. If you can’t identify an infestation in stored food products, inspect for alternative food sources such as animal hides, abandoned bird nests, dead insects inside wall voids, dried flower arrangements and other sources of food. Once the breeding location is identified remove the food source, and treat the area with an appropriately labeled insecticide to control any larvae that might be hiding in cracks and crevices nearby.
I had a customer with a significant Indian meal moth infestation in their kitchen. I am pretty confident that I located and removed all infested materials yet after a few days the moths appeared again; what’s happening?
Once the developing maggot has gotten its fill of the contents of your customer’s pantry, it leaves the food source to pupate elsewhere, often in cracks and crevices and behind frames and other wall-mounted items. The pupal stage can go unnoticed depending on how well hidden it is, and although you might have made some crack and crevice treatments, or even physically removed some Indian meal moth cocoons, maybe one or two slipped by you. You might want to try placing a pheromone trap in the area of the original infestation, and it wouldn’t hurt to conduct a re-inspection of foodstuffs and potential pupated sites while you’re at it.
I have been servicing a shipping facility that has been experiencing a major booklouse infestation. They are so tiny and the facility is so large that it has been really difficult to determine where they are coming from. When I put out sticky traps I seem to find them everywhere; what’s going on here?
The first and foremost thing to remember about booklice (pscocids), is that they have high moisture requirements, are tiny (1-2 mm), and typically feed on microscopic fungi. Even if the warehouse has below 50% relative humidity, which is near the lowest level required for booklice to survive, there are likely microclimates throughout the facility that provide sufficiently humid conditions for them. These pests are likely feeding on fungi growing unseen on cardboard, wooden pallets, or other receptive surfaces that absorb and retain moisture. Fixing the humidity problem inside the warehouse is a great place to start and it’s recommended that you check out any materials that are entering the facility to see if the booklice are being brought in from the outside.
COCKROACHES
How can I tell the difference between a German cockroach and an Asian cockroach?
The German cockroach (Blattella germanica) is one of the most ubiquitous pests on earth. Originally thought to have originated in Europe, then Africa, the most recent theories surrounding its indigenous range trace it to Asia. Today, it can be found on nearly every continent on earth (except Antarctica) and is almost always associated with human dwellings.
The species’ predilection for warm, humid environments make human structures, particularly areas where food is prepared, the perfect habitat for infestation. Anywhere that humans are found, cockroaches are probably present too. The Asian cockroach (Blattella asahinai), not to be confused with the Oriental cockroach (Blatta orientalis), has a more recent history of association with humans compared to German cockraoches. To the casual observer, and even the seasoned pest management professional, the Asian cockroach looks nearly identical to the German cockroach. They are closely related, but there are some key differences in behavior that make management methods different for the two species.
Asian cockroaches have longer and narrower wings compared to German cockroaches, along with a few other minor morphological differences. The most obvious difference is the ability of Asian cockroaches to fly. They are often attracted to lights and are most commonly found outdoors. In North America, the Asian cockroach is currently known to be established in Florida, Georgia, South Carolina, North Carolina, Alabama, Louisiana and Texas, but has the potential to spread further throughout the United States because it can be established indoors.
I have a commercial customer with a large atrium inside the building. I have collected multiple immature cockroaches that appear to be oriental cockroaches, but the adults I’ve seen have tan wings. The roaches seem to be living in the planters and mulched areas inside the atrium. Any ideas what they are?
The insects in question are Surinam cockroaches (Pycnoscelus surinamensis), an exotic species that is established in the Gulf Coast states. In the northern parts of the United States, it is primarily a pest inside greenhouses and indoor atriums. Adults are approximately 0.75 to 1.0 inch in length with wings that extend past the tip of the abdomen. The cockroach is uniformly dark brown except for the front and side edges of the pronotum and wings which are light brown in color. The nymphs look a lot like oriental cockroaches, but upon closer inspection you will notice that the last five abdominal segments have a dull, rough appearance in contrast to the glossy sheen of the rest of the body.
Believe it or not, all of the Surinam cockroaches found in the continental United States are females. It turns out that they reproduce parthenogenetically (without fertilization) resulting in the offspring being clones of the mother. No males have ever been observed for this species. A closely related species, P. indicius is found in Hawaii and the Indo-Malayan region, and has both male and female forms.
Surinam cockroaches typically prefer to burrow into loose soil, leaf litter or mulch and remain hidden during daylight hours. After dark, they emerge and feed on plant material, often causing substantial damage to plants in greenhouses and managed interior plantscapes. Harborage areas are sometimes difficult to identify since these pests are known to burrow three to four inches deep and only emerge under cover of darkness or following heavy watering of potted plants.
When inspecting sticky traps, I noticed two projections off the back end of a brown cockroach. What are these things and what purpose do they serve?
The projections you saw are called cerci, paired appendages and found on nearly every insect. In some species, the cerci (singular: cercus) are large and pronounced; while in others they are reduced and hardly visible. Given the discrepancy in appearance, you could rightly guess that they function differently for different insects. In cockroaches, especially pestiferous species, cerci provide a valuable service in predator aversion. Cockroaches love tight spaces, many of which allow cockroaches only to move forward or backward. In this position, the cockroach can use its antennae and cerci to detect air movement and vibrations from ahead and behind.
The most prominent cerci in the insect world belong to earwigs. Their cerci, commonly called pinchers, are used extensively in defensive behaviors, and will readily try to ‘bite’ you with them if handled. The presence and activity of their cerci is most likely a major reason why earwigs are both detested and feared by homeowners. For those identifying earwigs, this is a major feature used to separate species and even determine gender. Some are toothed, some smooth, some cross over each other while others do not.
FLIES
What are rattailed maggots?
The rattailed maggot is the larval form of the adult drone fly, a syrphid fly, of either species Eristalis tenax (Linnaeus) or Eristalinus aenus (Scopoli). Adults are so named because they resemble the male (or drone) honey bee in action and appearance, although the drone fly has just one pair of wings. The drone fly was introduced into North America sometime prior to 1874 and both flies are now common throughout all states. These flies are attracted by colorful flowers (especially yellow) as well as by odors.
The larvae of these flies are aquatic, rattailed maggots and are so named because of their appearance. The cylindrical, grub-like body may be up to 20 mm long with a very long tail-like breathing tube 30 to 40 mm in length. This hard-bodied life stage is resistant to crushing. Enclosed within the hardened skin of the last larval stage, the pupa appears a little shorter and fatter than the mature larva.
Rattailed maggots feed on decaying organic matter in stagnant water or moist excrement. Rattailed maggots are very rarely pests. However, occasionally, larvae appear in large numbers in dung pits or animal waste lagoons. They pose little threat to man or animals. However, in a few rare cases, intestinal myiasis (infestation by fly larvae) has been reported.
Drone flies have an unusual and little-studied life cycle. The female fly lays 4 or 5 eggs on or near contaminated water, sewage or other decaying organic matter. The larvae hatch from these eggs and then give rise to 7 to 30 daughter larvae in a bizarre parthenogenetic reproductive cycle. This method of reproduction may last for some time, but periodically female and male flies are also produced. Larvae can withstand many adverse conditions but are usually eaten by other fly larvae. Pupation usually occurs in a site drier than that in which the larvae developed.
Adult drone flies have never been implicated as disease vectors and usually do not become a problem if sewage and manure are not allowed to accumulate in pits, ponds, or streams. Client education and proper manure management will most often take care of any drone fly issues.
Our firm often gets requests to perform flea treatments, but we’re not sure what the service would entail. What can a pest management firm do to help control ticks on a residential property?
Most ticks prefer shaded habitats with relatively high humidity and do not survive well in areas with direct sunlight. To take advantage of this behavior, most pest management professionals approach tick control by focusing on the areas of a property where ticks are most likely to be encountered. Since ticks will rarely infest a well manicured lawn, the interface (called the ecotone) between the lawn and natural, wooded, or weedy areas is where the application should be focused. Some PCOs will use a high volume sprayer, to create a tick free “buffer zone” between the tick-free lawn area and infested natural areas. Many will also use granules for this treatment in conjunction with the liquid application. It’s important to find a properly labeled product to use for this treatment and make sure that you have the proper licenses/certifications to make pesticide applications away from the structure. The rules regarding licensing vary, so check with your state lead agency to determine what is required in your state.
In addition to the treatment described above, an important part of a tick management program is communication. It is good practice to recommend that your customer reduce the amount of weedy or overgrown areas on their property and limit their exposure to infested locations. Repellants containing DEET can be highly effective when used according to label instructions as well.
I have a ground floor apartment unit that has an infestation of small flies, they seemed to be concentrated around the diaper pail, but even after the customer removed it, the problem persisted. The flies look similar to fruit flies, but they don’t have red eyes. What can I do to control this pest?
The fly you are encountering is probably a phorid fly, also known as a scuttle, or humpbacked fly; both are common names for flies in the family Phoridae. These flies are sometimes confused with fruit flies because of their size and coloration, but there are a few simple identifying characteristics that can be easily recognized in the field to help you determine the difference. First, eye color can be tricky. Most people commonly associate red eyes with fruit flies, also called vinegar or pomace flies (family Drosophilidae), but not all fruit flies have red eyes, so using eye color is not as helpful as many people think. There are two easier ways to determine the difference. One approach is to observe the general shape of the insect. Phorid flies have a more humpbacked look, hence their other common name. Next, take a look at the fly’s rear legs. The section of the leg closest to the thorax is called the femur (analogous to the large leg bone connecting the hip to the knee in humans). Phorid flies have an expanded and flattened femur.
As for the infestation that you are observing in the apartment unit, it makes sense that the flies were hovering around the diaper pail. Phorid fly larvae live in and eat decaying organic matter and are often associated with contaminated soil adjacent to broken sewer lines. A diaper pail full of soiled diapers will probably provide a suitable secondary food source, but the chances are the problem is more complicated than that. Have building maintenance contact a plumber that is capable of identifying cracks or breaks in sewage pipes running beneath the slab. Often, phorid flies will breed in the contaminated soil and find their way into the living space through cracks, expansion joints or bath trap openings in the slab. If a broken pipe is found it, should be repaired and the contaminated soil should be removed and backfilled before replacing the slab.
I work at a cranberry production facility in which flies are very bad and found flying higher than one would expect from fruit flies and house flies. The flies congregate and fly around and land on white fluorescent ceiling lights. This is a regularly cleaned and sanitized stainless steel area in the cranberry processing facility. I never use pesticides or chemicals in this area. Do you have any suggestions as far as other possible control methods?
Since fruit flies especially are lower weight and less efficient fliers, typically they cannot fly this high of their own accord. The times we have seen flies flying higher than what their behavior and biology in textbooks would suggest was generally when they were either being transported by a conveyor belt, by the product on the conveyor belt, or by wind currents of fans and ducts within the facility.
Lights are a problem with most flies since they are positively phototactic (move to light). Can you switch the lights from white or fluorescent to yellow? (Flies do not perceive yellow wavelengths of light.) To prevent them from getting up that high in the first place, keep them low by using non-pesticidal fly light traps near the base of the conveyor. Also, encourage better sanitation measures around this product entry point on the conveyor. In addition, consider increasing air currents by applying a fan to keep the flies low.
I have a new customer that hired me to get rid of their cluster fly problem. My only concern is that it’s already winter…am I too late to do any good?
You are correct that you would have been much better off had they called you 2-3 months ago. Cluster flies are a group of 6 North American species in genus Pollenia and although they belong to the same family as blow flies, they are a different kind of pest. Cluster flies enter structures in the fall with the intention of overwintering in your warm house, preferring attics, structural voids, closets, windowsills, underneath clothes, picture frames, behind curtains, and other areas that are dark and protected. Once they have already penetrated a structure, like they have in your situation, things are quite difficult.
Fly control often centers on locating and removing breeding materials, but unfortunately that doesn’t help with cluster flies as eggs are laid in soil and maggots develop inside earthworms!
The two best forms of control are preventative: a thorough sealing of cracks, crevices, and other entry points into the structure, and a treatment of exterior surfaces that catch warmth and likely overwintering sites in the home with insecticides (tpyically dust formulations). Since those are not feasible options for this winter (though taking care of both of these by late summer next year could go a long way in reducing or preventing next year’s deluge), you are left without too many options. You can install ILTs in areas where they are found, physically remove them (vacuum with HEPA filter), seal off infested areas from the rest of the structure, and use insecticides. Treatments made after the flies have entered the structure can reduce populations but are unlikely to eliminate them.
These flies are quite annoying and can be numerous (hundreds to thousands) but they do not cause damage or transmit disease. They will likely stop being active in the coming days and stay that way until spring. When they do become active again they will attempt to flee the structure and probably be sluggish and easy to catch and dispose of in the process.
I recently got called out to a major small fly infestation in a first floor apartment and figured out that phorid flies are the problem. What’s the easiest way to determine the source?
Phorid flies breed in moist organic matter, which can be plentiful and available in numerous locations in and around an apartment building. The fact that only one apartment appears to be infested will help narrow it down, unless neighboring units are empty, non-responsive to such issues, or the apartment in question just happens to be the easiest way for the flies to surface. If you put fly boards around the unit, you can probably narrow down the general point of entry.
Consider all possible breeding sources and try to tick them off the list starting with the most likely and easiest to determine. Are there any obvious sources of decaying organic matter in or around the unit like visibly dirty drains, compost containers, overwatered plants, animal carcasses, dumpsters, garbage and recycling cans, grass clippings, organic debris under or around appliances, or a downspout causing an abundance of water outside the unit? The most difficult phorid fly problems are associated with plumbing problems like broken drains pipes under slab floors. Of course, these aren’t easy to check but there are a couple of tricks that can help you determine if that’s the source of the breeding material. Put pieces of clear tape sticky side down over drain openings or floor cracks while leaving some space in between them so air can still flow. This will catch adult flies as they are traveling between the breeding source and the rest of the apartment to help you pin point what is sustaining the infestation.
MOSQUITOES
What mosquitoes are capable of transmitting Zika virus?
Zika fever, caused by the Zika virus, has been detected in every country in North and South America with the exception of Chile and Canada. The symptoms of the illness include fatigue, joint and back pain, fever, skin rash, headache and eye redness. Most people infected with Zika fever show no symptoms. Most alarming is the association between Zika infection in pregnant women and a certain birth defect in infants called microcephaly, or reduced head size due to incomplete brain development. Microcephaly can result in a range of problems in children including developmental delays and intellectual disabilities. It’s important to remember that mosquitoes are not the cause of Zika fever. Instead, certain mosquitoes are capable of transmitting the virus that causes the disease. Zika transmission is most commonly associated with the yellow fever mosquito (Aedes aegypti), but the Asian tiger mosquito (Aedes albopictus) is also believed to be a competent vector of the virus. Both of these mosquitoes are present in the United States and the Caribbean and are aggressive daytime biters. The distribution of the yellow fever mosquito is restricted to tropical and subtropical climates. In the United States, it is primarily found in the Southeast and Gulf states with pockets in the Southwest and California.
The Asian tiger mosquito, on the other hand, is better adapted to cooler climates and has a much wider distribution, ranging into coastal regions of the southern New England states and into the Midwest, Southwest and California. Both species are commonly associated with structures, specializing in breeding in man-made containers with very little water present (Asian tiger mosquito larvae have been observed developing in containers as small as bottle caps). In addition to residual treatment of adult mosquito resting sites, any potential breeding sites on a client’s property should be identified and eliminated; including clogged roof gutters and drainpipes leading from downspouts.
NUISANCE WILDLIFE
We understand bats are beneficial critters, but we have been struggling for the past couple years with them coming into a customer’s attic. What can we do to prevent them from coming into our home?
It is illegal to kill bats in most states because they are protected. Young bats are born between April through August, which can make any type of removal and exclusion work difficult especially if there are young that are not ready to leave the attic. The best time for bat proofing is during September through March after the young bats have learned to fly.
It is important to first focus your efforts on safely removing the bats by constructing a one-way exclusion net around the entry points that are used by the bats. Bats are very small, and only need about 3/8 inch gap to slip through.
Once the bats are out, physical exclusion work can begin, which often takes the form of replacing pieces of siding or flashing, sealing gaps with caulk or mortar (ie: where the chimney attaches to the house itself), and securing a mesh screen behind attic vents and soffits. Exclusion work should be done on the inside and outside of a structure. Bats follow air currents, so if there is any light or air penetrating into the attic space between the wood frames, windows, or vents, use those as clues to potential entry points that must be sealed.
OCCASIONAL INVADERS
I have a client with a tremendous springtail issue. I found most of the springtails along the foundation of the customer’s house about 2-3″ down into the soil. She has some old mulch (of course holding moisture). But the springtails are also getting into the house, and onto the tile floor of the basement and her kitchen countertop. From my inspections, there are no moisture problems inside and it is a very clean house! Do you have any suggestions?
We recommend that you rake back the mulch from the foundation by about a foot to let it dry out in those areas. You may also apply some kind of material to the rake backed areas. Does this customer have an automatic sprinkler system that waters daily or on a regular schedule? This could be the issue. Dry out the area and adjust the sprinkler timer to be less frequent.
If you are also seeing springtails inside, check for plumbing leaks around sinks and drains and bath trap areas. Springtails cannot survive without moisture sources, and they often are good indicators of a problem plumbing issue. Dry out the area with increased ventilation, fans and dehumidifiers and address the plumbing issue. Various dusts may also be applied in wall void areas. When using such a product, always read and follow all labeled instructions.
We are hearing reports about the kudzu bug and are starting to get calls about it. What is the latest news on this pest and how can we control it?
The kudzu bug (Megacoptera cribraria) is an exotic invasive insect that was first observed in the United States in late 2009. First reports of this insect were from northeast Georgia, where pest management professionals encountered large aggregations of the bug on the sunny, south-facing sides of houses. Its presence has been now been confirmed in Georgia, North Carolina and South Carolina. Prior to being discovered in the United States, the species had been reported in Asia, the Indian Subcontinent and Australia.
The kudzu bug gets its common name because the invasive plant, kudzu, is one of its favorite foods. Unfortunately, in its native range it is also considered a pest on important agricultural crops like soybean. It is also known to feed on other crops such as beans, sweet potato, rice, wheat, citrus, potato and others. Kudzu bugs are known to have several generations each year. As temperatures and day length decrease, kudzu bugs seek shelter in protected areas including structures. Residential and commercial buildings located close to food sources (agricultural fields or kudzu stands) are at particular risk for invasion, since this species is an excellent flier. Similar to boxelder bugs, multicolored Asian lady beetles and the brown marmorated stink bug, kudzu bugs will congregate on the vertical surfaces of buildings to warm themselves in the fall. As temperatures cool they will move inside structures through cracks, crevices or other openings, to spend the cool winter months.
Treatment recommendations to manage kudzu bugs include exclusion by sealing potential entry points and screening vents and other openings. Bugs will begin migrating from food sources (typically kudzu or soybeans) as temperatures cool, and may continue for several weeks. Applications of appropriately labeled insecticides to surfaces where kudzu bugs may rest or into and around potential entry points may be useful. Wettable powder, microencapsulated or other longer residual formulations may offer the best results.
I found what I originally thought were gnats, but appear to be really tiny cicadas clinging to the inside of a window screen in a customer’s house. Are they cicadas? What are they doing inside the house?
The insects that you are encountering are called psyllids (SIL-ids) and are commonly called jumping plantlice. These insects are typically not a pest indoors, but may have found their way in from the outside through cracks and crevices as the weather cools. They can be a pest in ornamental plants particularly hackberry trees (Celtis occidentalis). The hackberry psyllids (Pachypsylla celtidisvesicula and P. celtidismamma) create galls on the upper surface and underside of hackberry leaves.
Adult psyllids overwinter in protected sites such as in cracks and crevices under loose bark or behind the siding of structures. After emerging from these sites in the spring, hackberry psyllids lay eggs on hackberry tree leaves. As the nymphs grow and feed on the leaves, the plant defends itself by growing abnormal fleshy tissue that surrounds the growing psyillid, creating a gall. Usually the presence of galls is not harmful to the health of a mature tree. Adult psyllids emerge from feeding inside galls in the late summer and will congregate on the sunny sides of buildings, eventually finding their way inside cracks and crevices around windows. Some psyllids are so small that they can even penetrate through screens with openings larger than size 18 mesh.
Psyllids are typically nothing more than a nuisance pest, and as the weather becomes colder, the infestation may resolve itself. However if the problem occurs year after year, it might make sense to recommend that the customer have any hackberry trees on their property showing signs of infestation treated with an appropriately labeled product. From an IPM perspective, psyllids are attracted to lights, so it makes also makes sense to address outdoor lighting to make the structure less attractive to these overwintering pests.
Since silverfish never develop wings and the immature stages look exactly like adults (only smaller) what kind of metamorphosis do they undergo?
The types of metamorphosis can be divided into two broad categories: simple and complete. Insects like beetles, flies, moths, wasps and fleas (holometabolous insects) all exhibit complete metamorphosis, which is characterized by four distinct life stages: egg, larva, pupa and adult. In insects with complete metamorphosis the adult and immature stages typically feed on very different kinds of food and live in different environments.
Simple metamorphosis is a little more complicated however, and can be divided into three sub-categories: incomplete, gradual and no metamorphosis. Incomplete metamorphosis is found in insects like dragonflies, mayflies and stoneflies (hemimetabolous insects). There are distinct life stages: egg, naiad and adult. The adult and naiad stages feed on different foods with naiads living in aquatic environments and possess gills which they use to “breathe” underwater. Gradual metamorphosis is a more familiar kind of simple metamorphosis because it is found in common pests like cockroaches, termites, bed bugs and stink bugs (paurometabolous insects). Gradual metamorphosis includes three distinct life stages, adults, eggs and the juvenile forms – typically called nymphs. Nymphal and adult stages usually feed on the same foods and will be encountered in the same kinds of environments. The last kind of simple metamorphosis is actually no metamorphosis at all. Silverfish and springtails (ametabolous insects) both fall into this category. The immature stages typically look the same as adults, feed on the same foods and are encountered in the same places. There is no major rearrangement or changes in body structure during development. The only major differences between adults and immature stages are size and the ability to reproduce. So, to make a long answer short, silverfish exhibit no apparent metamorphosis at all.
RODENTS
I have been battling a mouse infestation inside a pet food store for months and I don’t seem to be getting control. I think it’s because they are feeding on dog food that has been fortified with vitamin K and it’s counteracting the rodenticide bait I have been applying. What do you think?
You are correct; vitamin K1 is a treatment for anticoagulant poisoning. Vitamin K1 is the preferred method of treatment for poisoning with anticoagulant baits, since vitamin K3 is not as effective at reversing the acute effects of anticoagulants. However, the levels of vitamin K in processed pet foods are typically not high enough to counteract the effects of anticoagulant baits. At best, increased levels may slow the onset of lethal symptoms, but the end result will be the same.
I do suspect however that the rodent’s diet may have something to do with the challenges you are encountering with your control efforts. The abundance of competing food sources may be limiting the effectiveness of your baiting program. If you haven’t done so already, make recommendations to your client about promptly cleaning up spilled food. If they don’t already have a deep cleaning schedule, suggest that they develop a plan to periodically disassemble shelving and clean food debris that may have become hidden inside or underneath.
Additionally, you should consider a trapping program to “knock down” the population quickly. Traditional snap traps are one of the most effective ways to remove large numbers of mice in a short period of time. Consider placing multiple snap traps in all of the areas that droppings or mouse activity has been observed. In public areas of the store, you may need to wait until after hours to place the trap then remove them early the next morning. Remember to use plenty of traps. If there are 100 mice in the account and you only place 50 traps, the best you can do is catch 50% the first night. You might also consider baiting the traps with non-food items that might be attractive as nesting material like a small bit of yarn or a cotton ball. As for food baits, try using their normal food (dog chow) and some novel baits, like chocolate, peanut butter or anything else that the mice may not have encountered recently.
SPIDERS
More and more of our clients are becoming concerned about the brown widow spider. How toxic is their venom and what can we do to control them?
Brown widow spiders are becoming more widespread throughout the southern regions of the US, from California to Florida, and even up to Ohio and Michigan. Their coloration varies from light tan to dark brown, with variable markings of black, white, yellow, orange, or brown on the back of their abdomens. Their spiky tan colored egg sacs are more easily recognizable compared to the smooth white to tan surface of most other spider egg sacs. The brown widow’s venom is twice as potent as that of the black widow. However, brown widows do not inject as much venom as the black widow and are less likely to bite since they are more timid.
Brown widows primarily nest outdoors on the undersides of patio and lawn furniture, playground equipment, garbage bins, and other structures and items that offered horizontal support and underside access, according to a recent study completed by Dr. Richard Vetter from University of California, Riverside. Only on rare occasions, brown widow spiders were found in garages or sheds, usually if the door was left open for easy access.
Sanitation such as the regular maintenance of outdoor items, reducing clutter in storage areas, and disposal of debris and piled materials around the exterior of a structure will aid in reducing brown widow habitats. Exterior perimeter treatments may aid in preventing the spiders from entering a structure, but it is best to inject pesticide dusts or aerosols into holes and crevices where the spiders are likely to reside.
TICKS, LICE AND FLEAS
I’m dealing with a damp basement in Ontario that is practically covered in tiny white bugs. From the best I can tell they are not booklice, springtails, or any other pest I’ve encountered. I am planning to address the moisture problem and hope that will help because it’s become a real headache.
Even without a significant pest problem it’s probably a good idea to take care of the moisture issue. Based on your description I am inclined to think mites are probably the culprit. There are several species of pest mites that could be responsible for these basement problems including cheese mites, grain mites, flour mites, and other closely related species. They are probably feeding on microscopic mold that’s growing due to the excess humidity, though some of these species are more closely associated with infesting particular stored products (as evidenced by the common names mentioned above). Going after the moisture is definitely a great start and could take care of the problem on its own. Check out what products are labeled for this situation and consider making a treatment following, or in conjunction with, you efforts to control moisture. You will probably be surprised by how quickly the population dissipates once their preferred environmental conditions are no longer present.
What’s the best protection for pest management professionals against ticks?
Pest management professionals spend a lot of time in areas where they might encounter ticks as they perform exterior inspections and perimeter treatments. One of the best pieces of advice is to know where to expect ticks. Ticks live in moist and humid environments, particularly in or near wooded or weedy natural areas. Ticks are typically not found in well kept, sunny lawn areas, but if you venture into wooded areas, and ecotone areas (weedy transitional areas where the woods and grass areas meet) you are in prime tick habitat. Since ticks can transmit a number of different pathogens, including the germ that causes Lyme disease, its important to remain vigilant.
The Centers for Disease Control (CDC) offers these tips, which are helpful for work or play:
- Products containing permethrin kills ticks. Permethrin can be used to treat boots and clothing and can remain protective through several washings. Check the label and follow instructions carefully.
- Use a repellent with DEET on skin. Repellents containing 20% or more DEET (N, N-diethyl-m-toluamide) can protect up to several hours. Remember, repellents are pesticides. Always follow product instructions.
- Check your clothing for ticks and remove them. Placing clothes into a dryer on high heat for at least an hour effectively kills ticks.
- According to the CDC, showering within two hours of coming indoors has been shown to reduce your risk of getting Lyme disease. Showering may help wash off unattached ticks and it is a good opportunity to do a tick check.
- Check your body for ticks after being outdoors. Conduct a full body check upon return from potentially tick-infested areas. Use a hand-held or full-length mirror to view all parts of your body. Check these parts of your body for ticks:
- Under the arms
- In and around the ears
- Inside belly button
- Back of the knees
- In and around the hair
- Between the legs
- Around the waist
Email Michael Bentley, NPMA’s staff entomologist, for answers to your most challenging questions.
