Editor’s note: In early October, the Los Angeles County Department of Public Health issued a press release about an outbreak of flea-borne typhus in downtown Los Angeles. National news coverage, including stories on CNN, NBC and CBS, followed. A slightly edited version of the LA Department of Public Health’s release appears here, as well as information about fleas and typhus from the Mallis Handbook of Pest Control.
Murine typhus is an important flea-transmitted human disease caused by Rickettsia typhi. Transmission occurs when the bodies of crushed fleas or their feces are scratched into an open wound or onto mucous membranes. Symptoms include fever, headache, rash and malaise.
Murine typhus is a cosmopolitan and endemic zoonosis, most prevalent in warm regions with suitable flea vectors along with rats and opossums serving as reservoirs. Although current prevalence of the disease is fewer than 100 cases per year, murine typhus is still the second most frequently reported rickettsial infection in the United States. Murine typhus is perceived as a clinically mild disease, and cases often go unrecognized.
In the U.S., murine typhus is most prevalent along the southeastern, southwestern and Gulf coasts, with Texas and regions of Southern California having the highest prevalence. Epidemiological studies have indicated that typhus reservoirs and vectors are spreading.
Historically, X. cheopis has been considered the main vector of murine typhus, but outbreaks of endemic typhus transmitted by cat fleas from opossums have been reported in suburban areas of Texas and California (Civen and Ngo 2008). A similar disease, flea-borne spotted fever caused by Rickettsia felis, is maintained in opossums and transmitted to humans by cat fleas (as well as C. canis and Pulex irritans) (Pérez-Osorio et al. 2008). Because symptoms of flea-borne spotted fever are similar to those of murine typhus, diagnoses may be misattributed. Flea-borne spotted fever appears to be cosmopolitan, occurring where cat fleas are found. Source: Mallis Handbook of Pest Control
The Science Behind Fire Ant Rafts
Features - University Research
Arizona State University researcher’s 2006 paper on mechanisms of these disquieting sights gained interest last year thanks to insect upheaval caused by Hurricane Harvey.
“Life likes to live,” Kevin Haight said after viewing a photo of reddish-brown swirls in a floodwater eddy in southeast Texas. Haight, a researcher in the School of Life Sciences’ Social Insect Research Group at Arizona State University, was referring to tens of thousands of refugees uprooted by Hurricane Harvey.
Just not the ones you think.
The nation (or at least the media, both social and traditional) was transfixed by the spectacle of floating rafts of fire ants drifting through Houston’s floodwaters last year.
“Nightmarish.” “Creepy.” “Stuff of the Book of Revelations.”
There is a complex and fascinating story behind this survival behavior, however, one that evokes more sympathy than revulsion. You still won’t want to bump into a fire-ant raft after you hear it, but you will stare in fascination if you’re lucky enough to see one.
FIRE ANTS STING. There is a scale called the Schmidt Pain Index that attempts to systematize pain from insect venom. Created by an Arizona entomologist, it goes from pain level 1 (“a lover just bit your earlobe a little too hard”) to pain level 4 (“blinding, fierce [and] shockingly electric”). (See The King of Sting, PCT, August 2016.)
A single fire-ant sting rates a 1.2, with a honeybee sting rating a 2.
“However, that is for just for a single sting, which is not common to experience with (fire ants),” Haight said. “Multiple stings from multiple workers are much more usual.
“Furthermore, (fire ant) venom not only causes pain, which is felt almost immediately, but also causes tissue damage in the form of little pustules, which become evident hours to days after being stung and can lead to secondary infection if opened.”
Here’s the kicker: Their stings become significantly more painful and venomous when they’re rafting. How much more painful? Eighty-seven percent, according to Haight. He published a paper in 2006 describing his discovery, which to his amusement gained a great deal of attention last year after Hurricane Harvey.
Why are their stings more painful? It’s simple: They are at their most defenseless, and the survival of the colony is on the line.
WHAT HAPPENS. As the water table rises in the nest, the ants concentrate as dry space dwindles. As they do that, they gather the queen and brood (the eggs, larvae, pupae, workers). They’re becoming what people would refer to as “stressed.”
“The close proximity of so many workers during rafting may result in a concomitantly higher concentration of alarm pheromones, and thus the increase in defensiveness,” Haight wrote in his paper.
The water continues to rise. Now they float in the water above their nest.
They have some food with them. Their crop contains sugary liquids they can share with larvae and each other. (Fire ants do stash “ant jerky” in their nests — dried protein flakes — but they don’t carry it with them in a flood. As Haight pointed out, “If your house is on fire, what are you going to do — empty the fridge or grab your kids?”)
They’re floating, and they hold on to each other. They cycle from the bottom of the raft to the top in a convection pattern. The rafts are more buoyant if they have larvae, research has shown.
They are completely at the mercy of the current.
“They are a rudderless boat,” Haight said. “They have no control over where they end up. Typically it’s downstream.”
Now the ants are at their most dangerous. Large concentrations of workers are exposed, available for defense, and loaded with more potent venom. They’re also on high alert to grab on to something, anything, and get out of the water.
“If they bump against a tree branch or something in the water, they’ll do that,” Haight said. “It’s one of the things that makes them dangerous in a flood situation when you have people wading or people in boats. If the ants bump up against a boat and they’re able to climb up the sides, then they’re in the boat with you now.”
When they hit dry ground, they will begin digging a new nest. They are incredibly efficient diggers. Depending on how hard the ground is, they can dig a new nest and get the whole colony underground in five to six hours, Haight said.
“They’re never more vulnerable than when they’re rafting,” he said. “They have no place to go. They can’t go deeper in their nest because they don’t have a nest.”
Animals or people trudging through water could break the colony up, or predators like fish. The colony could perish. Without a big workforce, survival becomes dicey. Increasingly painful stings increase the likelihood of survival.
“I would argue that yes, it is an adaptive survival mechanism,” Haight said. “Higher venom doses mean more pain delivered to a threat in a shorter amount of time, which translates to higher repellency. This would be especially important to a rafting colony since quick repulsion would reduce the chances of worker loss, which would be beneficial since colonies with more workers will have a higher chance of reestablishing a successful nest and territory after the flood recedes.”
Source: Arizona State University
Features - Invasive Species
The story of the little fire ant, and why modern medicine can learn from indigenous cultures.
Editor’s Note: This article originally appeared in Entomology Today, a project of the Entomological Society of America with the goal of reporting interesting discoveries in the world of insect science and news from various entomological societies. To learn more, visit www.entomologytoday.org.
Lesions of the cornea that cause white discolorations of the eye, called leukomas or corneal opacities, have been discovered for decades in humans, domestic animals and wild animals. Sometimes called West Indian punctate keratopathy, Florida spots or Rice’s keratopathy, this condition was a mystery to the medical community. But a recent paper in the Journal of Medical Entomology reports that the cause of these lesions has been known for a long time by indigenous peoples in Colombia. What is the cause? Wasmannia auropunctata, also known as the little fire ant.
Diego Rosselli, Ph.D., of the Pontificia Universidad Javeriana in Colombia and James Wetterer, Ph.D., of Florida Atlantic University co-authored the report, in which they gather knowledge on the condition from disparate sources to better inform the medical community.
The corneal lesions were first reported in the medical literature in 1968 by Noel Rice, who noticed it in immigrants from the West Indies in London. Rice came to the conclusion that the condition was caused by trauma to the eye. The lesions were then reported in cats in Florida in 1979 and in dogs in Brazil in 1997. In 2004, corneal lesions were reported in cats and dogs in Martinique, but they were only found in animals that lived outdoors.
Other potential explanations for the corneal lesions were proposed in the literature, including viral infections, bacterial infections and inflammation resulting from exposure to the microfilariae of the parasitic worm Onchocerca volvulus, the worm that causes river blindness.
None of these researchers were aware of the true cause of the lesions — but indigenous cultures in Colombia have known the cause for a long time — stings from the little fire ant, Wasmannia auropunctata. The lesions could arise from other causes, but, as Rosselli and Wetterer write in their paper, if there was no trauma to the eye and there was no infection, W. auropunctata is the cause.
The little fire ant originated in the lowlands of Central and South America. Carried by human trade, it has spread to Florida, Africa, Israel, Australia and many Pacific islands, including Papua New Guinea, Hawaii, the Solomon Islands and the Galapagos. The ant creates a toxin that, when it stings the eye, can cause corneal lesions. The stings often occur when humans or animals blink in response to the presence of the ant, and the blinking triggers the stinging.
“Indigenous knowledge, which is normally neglected, has observed the association for many years. Thus, scientists should try to be aware of discoveries in fields different from their own,” says Rosselli.
Asked what the biggest surprise of the study was, Rosselli says, “Ants represent a large proportion of all insects (and therefore of all animals), but their association to human diseases has been scarcely explored.”
WHAT’S NEXT? Regarding next steps in this research, Rosselli says research on the chemistry of little fire ant toxins could be valuable: “I was surprised to know that despite the impact of this ant in agriculture, in animal diseases, and, with our paper, in human disease, very little is known about the toxins produced by the little fire ant (as compared with its larger relative the big red fire ant).”
As for possibilities for control of the little fire ant, Rosselli says results of studies have been mixed. In Florida, for example, insecticides were very effective in reducing populations of the little fire ant. But, when the insecticide use is scaled back, the ants tend to return. Physical methods such as applying scalding water to colonies, or excavating and removing colonies, also can be effective. Biological control methods may offer the greatest promise. The little fire ant is more destructive in regions where it has invaded than in its native habitats, which might be a result of biological control from species present in its native habitats. Introduction of such biological control species might be effective in helping to control outbreaks in other regions. To prevent eliminating biological control species, insecticide baits are most effective if they focus on mounds with a colony of the little fire ant, rather than being broadcast to a wider area where other species could be affected.
Agricultural workers are sometimes exposed to the ants when harvesting products, in settings such as citrus orchards, cacao orchards and palm tree plantations. Domestic animals are sometimes exposed when the ants are in their food bowls. Rosselli mentioned that goggles might be used by workers in some agricultural settings, such as palm tree plantations, and insecticides might be applied to animal food bowls to keep the ants away from domestic animals.
One characteristic that makes control of the little fire ant so problematic is that the ant is a “tramp species,” spreading throughout the world via human commerce. Increased inspections of agricultural products, and quarantines of products infested with W. auropunctata, could be useful components of control.
John P. Roche, Ph.D., is an author, biologist, and science writer dedicated to making rigorous science clear and accessible. He has a Ph.D. in biology and has published more than 180 articles. For more information, visit http://authorjohnproche.com.
Mean, Mysterious Brown Rats
Features - RODENT RESEARCH
How the brown rat conquered New York City (and every other one, too).
Editor’s note: This article originally appeared in the Oct. 27, 2016, edition of The New York Times with the headline “How the Mean, Mysterious Brown Rat Took Over Cities.” It is reprinted here with permission.
Millions of them live in New York, and billions more in cities and on farms across the globe. And wherever they scurry, they wreak havoc.
They devour food supplies and contaminate what they don’t eat with feces and urine. They spread a range of harmful viruses and bacteria. In delicate ecosystems around the world, they threaten other species with extinction.
“They’ll gnaw through walls. They’ll gnaw through wires. They’ll destroy cars,” said Jason Munshi-South, a biologist at Fordham University. “They’ve managed to spread wherever there are humans.”
Despite their ubiquity, Rattus norvegicus, otherwise known as the brown rat, remains surprisingly mysterious. Scientists have only a hazy idea of how it went from wild rodent to unwanted human companion.
Now Dr. Munshi-South and his colleagues have completed the first in-depth genetic study of brown rats from around the world. Their story has twists and turns that surprise even the experts.
After spreading slowly for thousands of years, the scientists found, brown rats scampered over much of the planet in just the past three centuries. And once brown rats settle into a new city, the new study suggests, they repel all newcomers — a finding that could have big implications for our health.
Dr. Munshi-South said the study emerged from a simple question: “What is a New York City rat, and where did it come from?”
He contacted researchers around the world to see if he could obtain DNA to compare with that of the rats he captures around New York City. To his surprise, he ended up with samples from hundreds of brown rats, from the Galápagos Islands to Brazil, from New Zealand to Japan.
Instead of simply asking where New York City’s brown rats came from, Dr. Munshi-South realized he might be able to figure out where the world’s brown rats came from.
Emily E. Puckett, a postdoctoral researcher in his lab, analyzed the DNA samples, sorting 314 brown rats from 30 countries into clusters of genetic relatives. Eventually, she was able to determine how different populations of the rats mixed together over time.
Dr. Puckett, Dr. Munshi-South and their colleagues published their findings in Proceedings of the Royal Society B Biological Sciences.
The brown rat is sometimes called the Norway rat, but the new research confirms that the name is a misnomer. Instead, brown rats originated in northern China or Mongolia. Before they became our companions, they fed on wild plants and small animals on cold, open plains.
Farming came relatively late to northern China, but at some point, native brown rats, finding a reliable food supply in their midst, switched to living on farms and in villages.
Dr. Puckett and her colleagues can’t say how long brown rats remained in northern China, but at some point, they started to expand their range. Their first migration, the study suggests, took them to southeastern Asia.
Much later, a wave of brown rats spread northeast, into Japan and Siberia. Another emigrated west, eventually reaching Europe in what appear to have been three major arrivals on the continent. These rats may have traveled on overland routes, or perhaps hidden on ships that sailed along the coasts of Asia and Europe.
The study suggests that brown rats were slower to spread around the globe than our other familiars, the black rat and the house mouse. Geography may be the reason: House mice originated in the Fertile Crescent, and black rats in India.
Farming societies and widespread trade arose in those places much earlier than in northern China, giving the black rat and the house mouse early opportunities to travel.
But in the past three centuries, the brown rat has more than made up for lost time.
Brown rats in Alaska and along the Pacific Coast of the United States and Canada can trace much of their ancestry to Russia, Dr. Puckett and her colleagues found. Their ancestors may have stowed away aboard ships that traveled to fur-trapping communities in the New World in the 1700s and early 1800s.
But the brown rats of Europe became the true globe-trotters. As Western European countries colonized other parts of the world, they took the rodents with them.
The brown rats of New York and other Eastern American cities trace their ancestry to those in Western Europe. So do brown rats in South America, Africa, New Zealand, and isolated islands scattered across the Atlantic and Pacific.
Even today, the ports of New York City are visited by rats from around the world. Before his new study, Dr. Munshi-South had originally suspected that the city’s rats would have inherited a mix of genes from ancestors far and wide.
But he and his colleagues found very little evidence of genetic mixing in New York, or in the other cities they studied. “You don’t see a lot of recent migrants arriving and reproducing,” he said. “There’s some force keeping them out.”
Michael Kohn, an evolutionary biologist at Rice University, said the difficulties that brown rats now encountered in cities was intriguing. “It’s not hard to get there,” he said. “But it’s hard to get in.”
The reason may be that brown rats are territorial and just plain mean, as Dr. Munshi-South often is reminded when he inspects the specimens caught in traps. Many of them bear the marks of fights with other brown rats.
“They’ve got scars, they’re missing eyes, they’re missing part of their tail,” he said. “Their life is fairly brutal.”
The researchers now theorize that the first brown rats to show up in a city rapidly fill it up. Later, when bedraggled latecomers tumble out of ships in the city’s ports, the stronger residents rebuff them.
To Dr. Munshi-South, that’s good news. “It’s unlikely that a lot of diseases are going to be entering cities on rats walking into the local rat population,” he said.
If that’s true, then the study also contains a strange paradox. As much as we dislike brown rats, they may be our staunchest defenders.
Editor’s note: See part one of this series in the July 2018 issue of PCT.
It’s not often an entomologist knowingly moves into a house that harbors brown recluse spiders, but we finally moved into our new home in April this year after a long remodeling project. In the first article of this series, I reviewed the various pest-conducive conditions associated with the house and the solutions I chose to remediate those issues. This article will delve into greater detail the efforts at excluding pests from a home that is located in the country and backs up to an agricultural field.
FIRST, AN UPDATE. When the house was purchased, the crawlspace was damp with no vapor barrier and the vents were all blocked off. This lack of ventilation resulted in higher moisture content in the wood. After a year with vapor barrier and Temp-Vents installed, the moisture content is not where I’d like it to be so I am installing two powered Temp-Vents to further ventilate the substructure. Bora-Care with Mold-Care has been applied and the surface molds on the floor joists and other wood are dying and the wood is further protected from future mold and fungi.
Routing the downspouts via drain pipes to the pond did not fully solve the water accumulation beside the foundation. The problem was the small, 4-inch gutters originally installed on the house were not suitable for containing the amount of rain coming off the roof during heavy rainfall (a regular occurrence in my area). Down came the 4-inch gutters to be replaced by large 6-inch gutters, thereby stopping the waterfall out of the gutters to the foundation area.
PESTS INVADE. During the year we’ve owned the house, I have noted a number of pest incursions, the most notable was a large invasion of black ground beetles (Synuchus sp.) in the late spring. This invasion is related to bright white LED bulbs on the garage and the worn and damaged weatherstrips on the bottom of each garage door (more on this later). I caught one mouse in the garage in June, also due to the bad garage door weatherstripping.
I had discovered a couple of bird carcasses in one of the attics, then this spring black birds set up a nest in the same attic. This indicated a large-sized gap somewhere at the roof line that was not visible from ground level. Closer examination using a 24-foot ladder revealed, like the rest of the house, this corner lacked gutter apron flashing to close off the gap between the fascia board and the roof subdeck (see Figure 1).
A number of nests of two species of paper wasps (Polistes carolina and P. fuscatus) invaded the roof returns and the attic (via the lack of gutter apron). Mud dauber wasps also were invading the attic via the same routes — numerous old nests are present all over both attic spaces. Also, when we first bought the house, I would find paper wasps and mud daubers several times a week inside, likely entering from attic spaces through one of the many can lights in the house. The can lights on the back porch were filled with old (and some active) mud dauber and paper wasp nests.
Last fall, Asian multi-colored lady bugs (Harmonia axyridis) made their presence known in large numbers off the back balcony, invading the bonus room space in that area in significant numbers. Strangely though, this was the only room with many lady beetles even though you can find dead lady bugs in the attic spaces.
Other invaders were occasional in nature: a few wolf spiders, flies, and house and cellar spiders.
EXCLUSION CONTINUES. Any house has multiple entry points for pests, with larger pests (rodents, birds) being easier to completely exclude, while smaller creatures (insects, spiders) are more difficult because finding and sealing off every tiny crack is nearly impossible. Even so, a great deal of insects and spiders can be excluded with reasonable exclusion efforts and investment.
Garage — Replacing the weatherstrips along the bottom of all garage doors is not difficult but does take some time in labor. After removing the old weatherstrips, I installed the Xcluder Rodent Proof Garage Door Seal onto the bottom of each door. Prior to installing these, I would regularly find toads in the garage and also discovered and captured one mouse after placing a snap trap. Since, then no mice, no toads inside.
Soffits & Gutters — I waited until I replaced the gutters to install gutter apron flashing to cover the gaps that exist between the fascia and the roof subdeck (Figure 1). This gap exists on all conventional pitched roofs and should be closed off to prevent rodents, birds, bats, bees, wasps and overwintering pests (cluster flies, lady bugs, stink bugs) from entering the attic spaces through this entry point.
A gutter apron is a simple item to install as it slides under the shingles onto the roof subdeck on the roof side and down into the gutter, attached into place via nails or screws. Its primary purpose is to prevent rainwater from wrapping around the shingle edge back into the soffit, but just as critical, it serves as a shield against pests entering the soffit. It also helps keep moisture out of the soffits.
Once the gutter apron is in place, many people forget about the corners and edges of the soffits and leave gaps and cracks open where insects could still enter. At corners of roof valleys, you may need to install an additional flat flashing on top of the back edge of the gutter apron because the aprons do not completely close off the gap under the shingles at these corners. Figure 2 on shows how Xcluder Rodent Control Fill Fabric was used to close off gaps at the edges of the gutter apron. Xcluder Fill Fabric or silicone sealant also was used to close off other cracks found around the soffits and roof line.
Roof Returns — A roof return is located wherever one roof ends along the roof of another portion of a house (see Figure 3). Builders usually leave gaps at the bottom of roof returns, some large enough to allow rats or squirrels easy entry into attics. Such gaps need to be closed off with metal flashing, molded to best fit over the gap. Still some small cracks or gaps remain, which may be covered with a small metal flashing or stuffed with Xcluder Fill Fabric. Prior to sealing off the roof returns on my house, I had to treat each one using residual dust to kill active paper wasp nests residing within many of the returns.
Brick Siding Trim & Other Exterior Cracks — My house is brick veneer with wood trim and IFAS siding on upper sides of the house and clapboard siding on one porch. Cracks exist wherever wood or siding meets the brick. Some gaps are large enough on the porches to allow mice or a small rat to be able to squeeze into the attic or serve as points for paper wasps or yellowjackets to enter and build their nests. These cracks also were being used by lady bugs and other insects to enter into the attic and walls of the home.
The wood-to-brick cracks were sealed off using clear silicone sealant for small cracks and Xcluder Fill Fabric for larger gaps. Xcluder Fill Fabric is available in 4-inch wide and 1-inch wide rolls, which were alternated depending on the size of the gap being filled. Eventually, the Xcluder in larger gaps occuring around the walls on the three porches will be covered using white mortar mix that matches the mortar lines in the brick siding. After treatment with residual dust, 1-inch Xcluder Fill Fabric also was used to fill in holes around hose bibs and AC lines and was placed into weep holes in the brick siding.
Foundation & Attic Vents — My foundation vents were already equipped with decorative metal grates with insect screen behind this. The Temp-Vents added another layer of insect screening. Should I later find rodents entering the crawlspace, I will attach ¼-inch hardware cloth to cover the Temp-Vents inside.
My house has three types of vents — soffit vents, gable vents and turbine vents, and I plan to eventually install ridge vents along the peaks of the roof. Ridge vents serve to better ventilate the attic, which helps with HVAC costs and also can extend the life of roof shingles. My gable vents and soffit vents are adequately covered with insect screening but the turbine vents have no screens. For these turbine vents, inside the attic, I attached a piece of ¼-inch hardware cloth over the opening and behind this, I added a piece of insect screen. The hardware cloth will exclude rodents while the screen excludes wasps and other insects. Should I discover rodents entering through the gable vents, I also may need to also add hardware cloth over these.
Other Exterior Doors — My regular exterior doors are all fairly tight-fitting but I added Xcluder Residential Pest Control Door Sweeps to the bottom of each ground floor door. A second story balcony doorway, however, proved more problematic. After moving in, I discovered the doorway was leaking during heavy rain. When I examined it more closely, I found that the door threshold was not attached to the floor underneath as it should be because the door itself was ¾-inch too short for the framed opening. Also, the joists for the cantilevered wood balcony into the room’s floor space had gaps, also allowing water to enter.
Despite the expense, a new, vinyl door was purchased and installed (of course it was a custom opening requiring a custom-sized door). After this, I had to pull up deck boards on the balcony, and use silicone sealant to seal off the gaps around all the deck joists where they enter the brick wall. I then fashioned a fitted metal flashing that covered horizontally from the threshold then vertically down onto the wall, around each joist. Silicone sealant was then used to close off all gaps and cracks along all edges of the flashing. This solution resolved the leaking issue and closed off another avenue where insects could enter into the walls.
Can Lights — Can lights create a pest entry opportunity into the living spaces of a home from the attic and ceiling voids. Wasps, flies, lady bugs and similar insects that may enter an attic can be attracted to light emitting through the vent cracks on the can light housing. From there, the insects enter into the rooms below. In my case, I had paper wasps and mud daubers entering the home and when I removed the bulb and pulled off the decorative outer ring, I uncovered brown recluse spiderlings in many of the lights. Recluse spiders will use gaps around ceiling fixtures and can lights to enter rooms from ceiling and attic spaces.
To fix this issue, I first applied residual dust into the space behind each can light, using the vent holes in the light housing. I replaced the bulbs with LED retrofits designed for can lights (see Figure 4). The LED retrofits close up tight to the ceiling and leave very little gap for insects or spiders to enter. The LED lamps also use far less energy and also give off no appreciable heat. They come in dimmable versions, which was needed in certain rooms. The LED retrofits also stopped wasps from building nests in the six can lights on the back porch.
Plumbing Penetrations — Wherever plumbing pipes and drain lines entered the walls under sinks and behind toilets, the wall voids behind were treated using residual dust and then sealed with sealant and escutcheon plates fitted tightly to the wall around each pipe. This step should keep recluse spiders from exiting walls in these sites.
Windows — Though not absolutely necessary, we decided to upgrade windows from wood to vinyl windows in much of the house. This installation closed off these sites from pests being able to enter around windows.
Other Exclusion Issues — The dryer vent was missing a vent cover so a self-closing cover vent was installed over the vent pipe outside. While repairing a whirlpool bathtub, a large opening in the floor around drain lines was discovered which, based on the mouse droppings, allowed at least once mouse to enter. This opening was effectively closed off using Xcluder Fill Fabric.
Back Porch — Mosquitoes were making it unpleasant to use the back porch. Searching online, I found www.mosquito curtains.com, which offers custom screened curtains that I installed across the opening to the porch. This was a much lower-cost alternative to converting the porch to a permanent screened-in porch (see Figure 5). The curtains were easy to install and also keep birds, mud daubers and paper wasps off the porch.
Summary. It will be interesting to see how effectively all these exclusion efforts will be in limiting incursions of various pests into the home. Will I see many lady bugs inside this fall compared to last fall? Will I see any more mice? How many paper wasps will successfully be able to nest in or on the house next summer? Will I see fewer ground beetles and wolf spiders inside? Only time will tell.
The author is with Stoy Pest Consulting, Memphis, Tenn.