Editor’s Note: This article was reprinted with permission from Techletter, a biweekly training letter for professional pest control technicians from Pinto & Associates.

The life span of an individual bed bug can vary considerably, from months to years. That variability depends primarily on temperature and other environmental conditions, the quality of food (blood) and its availability, and genetics. The average length of a typical bed bug’s life span from egg hatch to death in a laboratory environment, with ideal conditions, is six to 12 months.

But life in the real world is very different for a bed bug, and usually much shorter. Bed bugs living around someone’s bed face competition from other bed bugs, chemicals (cleaning and insecticides), crush risk during feeding, predators (spiders, ants, etc.) and other risk factors. Female bed bugs have higher mortality due to the risk from traumatic insemination (the male actually punctures her abdominal wall to plant sperm) during mating. If a bed bug survives all that…in the real world, temperatures fluctuate and rarely approach the ideals of lab conditions. Food, in the form of animal blood, doesn’t always appear on a regular basis in the real world either.

WHAT AFFECTS LIFE SPAN? Within a certain range, as the temperature goes up, bed bugs develop more quickly. The average development time from egg hatch to first egg laying is one to two months. At 80^°F (27^°C), egg to egg development time is about one month; at 64^°F (18^°C), that same egg to egg development takes four months.

Bed bug activity and development stops completely at certain temperature extremes, although exactly what those extremes are is debated. Earlier laboratory work found that bed bugs became inactive at temps below 57^°F (14^°C). Other studies though found still active bed bugs at temperatures as low as 44^°F (6.6^°C). Temperatures of approximately 97^°F (36^°C) seems to be the upper point at which bed bugs cease activity.

While temperature is a very important variable affecting bed bug life span, humidity seems to have little impact on the growth and development of bed bugs except at the extremes. Very low humidity increases desiccation and very high humidity can mean the growth of fungi.

FOOD AVAILABILITY. A bed bug normally feeds two to three times a week, and a blood meal is necessary for egg laying. But, a blood meal can be difficult to find at times, say when an apartment becomes vacant or a wilderness cabin is unused over the winter. Not to worry, bed bugs seem to have adapted to starvation and while egg laying may be put on hold, bed bugs can survive for surprisingly long periods without blood. Adults and late instar nymphs survive significantly longer than early instar nymphs, more than a year under certain conditions. Some experts have said that newly hatched nymphs will die within a few days of emerging from the egg if they do not locate a blood meal. Others say the young nymphs can survive for months.

Here’s where temperature comes into play again; temperature makes a difference in survival time in the absence of food. Starved bed bugs survived five to 10 times longer at 50^°F (10^°C) than at 80^°F (27^°C). This was true for all stages of the bug.

Recent studies suggest that bed bug development times also can vary with different bed bug populations. When three strains of bed bugs were compared, the time from egg to adult ranged from 35 to 40 days. One population of bed bugs that was highly resistant to pyrethroid insecticides developed significantly faster than the others.

WHAT DOES IT MEAN? You may need to rethink your criteria for declaring an account “bed bug-free.” Residual bed bug populations can remain alive in protected harborages for months after treatment, or while furniture is in storage, or during an extended period while rooms or structures are unoccupied. Vacating an infested room, or even an entire apartment so the bed bugs can “die out,” is not a feasible strategy for pest management professionals. Bugs won’t die any time soon and are apt to migrate to a new location where they can find new hosts.

Industry practice seems to be to wait seven to 10 days after bed bug treatment, than evaluate the success of the treatment. This doesn’t take into consideration temperatures at the account. Bed bug eggs at cool temperatures can take up to 21 days to hatch, long after you’ve declared the account bed bug-free.

It’s easy to understand why bed bug problems generally peak in the summer months, being greatest from July through September. Bed bugs develop faster at higher temperatures, and they are also more active and more noticeable. Even in accounts with air conditioning, the average indoor temperature is warmer in summer than in winter.

The authors are well-known industry consultants and co-owners of Pinto & Associates.

Property managers often ask technicians, “When can I rent this hotel room?” or “When is it safe for new tenants to move into a previously infested unit?” These are difficult questions for technicians to answer and they’re loaded with liability. “The inconvenient truth is that there is no way to know for sure,” Larry Pinto, entomologist and publisher of the industry newsletter Techletter, told attendees of PCT’s Bed Bug Virtual Conference last year. Even following aggressive, repeated service, some bed bugs and eggs can survive. Clearly, many hotel rooms go back into service before all of the bed bugs and eggs have been killed.

Keeping rooms vacant for long periods of time isn’t the answer, although some hotel managers think it is. Remaining bugs will simply wait for a new host or move to adjacent rooms, or both. Bed bugs are less active and their locations more unpredictable the longer a room is vacant.

There are ethical and legal consequences for both the hotel management and pest control company associated with the decision as to when to put a hotel room back into service. Bed bug service calls should take this into account. Treatment options may include installing bed bug monitors in the vacant room to actively attract bed bugs. Inspect rooms using a bed bug canine scent detector in conjunction with active monitors before you release it into service. Don’t just allow the hotel to put the room back into service without having the option to check it and neighboring rooms again. Include a comprehensive follow-up inspection and service program for a few weeks.

The only situation more challenging than deciding when to put a hotel room back into service is when to re-occupy a residential property that was vacated with an active bed bug infestation.

Tenants may terminate their lease and leave after they discover they have bed bugs, without telling management. Property managers may first learn that an apartment has a bed bug infestation when maintenance staff prepares the unit for the next tenant.

Try to eliminate a bed bug infestation before a unit is vacated. Property managers should consider requiring, upon lease termination, a pest inspection to be conducted before the resident leaves. If the inspection uncovers evidence of bed bugs, there may be time to eliminate the problem before the resident moves. If the infestation isn’t discovered until after the resident vacated, you’ll need aggressive measures before putting the unit back on the market.

“The longer the unit remains vacant, the greater the likelihood that any bugs will migrate into surrounding units in search of a blood meal,” Pinto said.

Consider steam cleaning carpets, particularly edges and joints, before insecticide treatment. One option is to temporarily remove the baseboards and moldings to enable a more thorough application and eliminate protected harborage. Spray residual insecticides around the perimeter of all rooms and the intersection of floors and walls. Install active bed bug monitors. Regularly check them and inspect the unit. Consider using canine detection before the unit goes back on the market. Inspect neighboring units regularly for one month after the vacant unit is re-occupied.

Include bed bug inspections with routine service calls to avoid the sensitive issue of bed bugs. To protect yourself legally, keep detailed records of every action to demonstrate that you’ve taken reasonable steps to minimize the risk of bed bugs.

The author is a Florida-based freelancer who frequently writes for PCT.

Editor’s Note: This article was reprinted with permission from Techletter, a biweekly training letter for PMPs from Pinto & Associates.

The deer mouse first became widely known because of its role in the transmission of hantavirus and as a reservoir for Lyme disease, but it has become an important indoor mouse pest in many areas of the United States. It is found throughout most of Canada and the U.S. except for a few southeastern states.

The deer mouse, Peromyscus maniculatus, is hard to tell apart from the closely related white-footed mouse, Peromyscus leucopus, and the term “deer mouse” is often used for both. Because the deer mouse and the house mouse are similar, we’ll concentrate on how their differences.

Most notably, the deer mouse has a two-tone coloration, usually a tawny brown (sometimes gray) on its back with a pronounced dividing line between its white belly, with white feet and white on the bottom of its hairy tail. The mostly gray house mouse has a mostly naked tail. The two mice are about the same size, but the deer mouse has larger, prominent eyes and larger, thinner ears than the house mouse.

Outdoors, deer mice will nest around the roots of trees, under boards or logs, in stumps or woodpiles, in animal burrows or bird nests, in sheds or in abandoned vehicles or equipment. Deer mice are active year-round, mostly at night, and can damage garden crops.

ROLE AS A STRUCTURAL PEST. Deer mice are good climbers and use vines and tree limbs to reach attics or upper levels. Favorite indoor nest sites are drawers and storage cabinets in garages, items stored in attics, upholstered furniture, wall voids and corner sill plates in basements and crawls.

These mice feed on a variety of foods but particularly like seeds and nuts and will cache large amounts near their indoor nests. Deer mice urinate and defecate in their nests and will build a new nest when the current one becomes too foul. Hantavirus is a concern for people in dusty environments with a large amount of deer mouse urine and droppings.

Deer mice indoors are controlled in the same way as house mice. Baited snap traps work, as do rodenticide baits. Use secured block baits and avoid loose baits because of the deer mouse’s habit of hoarding without eating. Make sure deer mice are listed on the label.

POINTS TO REMEMBER. The deer mouse is the most common small mammal in North America and is generally seen as more of a rural, outdoor mouse, occasionally found in sheds, cabins or barns. But it has become increasingly common in homes, especially those surrounded by natural habitats. Deer mice often move in with cooler fall weather.

The authors are well-known industry consultants and co-owners of Pinto & Associates.

In the city of New Orleans, rats face a formidable opponent. Timmy Madere, special projects coordinator for the City of New Orleans Mosquito & Termite Board, is an expert in urban pest issues and rodents. When the call for help goes out, he relies on tracking, trapping and technology to rid buildings of rats and mice. In PCT’s Rodent Control Virtual Conference hosted late last year, Madere shared techniques that pest management technicians can use, guided by old school Sherlock Holmes observation skills and technology tools.

DETECTIVE WORK. Madere has learned through extensive field and research experience that successfully tracking and trapping rats begins with detailed detective work and an open mind. Sherlock Holmes inspires many throughout the pest management industry and is famous for his detective approach, emphasizing thorough inspections using observation, reason and logic. Looking closely at all the evidence before making assumptions — the difference between simply seeing and observing — also is key to helping technicians determine the source of rodent activity and set the course for an effective rodent control program.

A recently encountered trash can reinforced this point for Madere. The can had become a convenient food source for rats and it would have been easy to assume rodents chewed their way into the trash can through the bottom. However, after close inspection, small scratch marks were discovered in the sides of the plastic trash bag leading out the top of the receptacle. They revealed the rat was entering and exiting through the top of the trash can, not the bottom, and it was found sitting inside. Had the scratch marks gone unnoticed, traps placed underneath the can may have never solved the issue.

In another case, similar observation techniques were combined with technology to gather detailed evidence used in solving a basement rat problem. Droppings found around a sewer pipe suggested rats were traveling into the building through the open pipe. Building engineers resisted, not believing rats would use a pipe connecting to sewer water as the entrance or escape route. Madere installed a camera and with video footage of a rat poised on top of the open pipe, he quickly made the case to the client to plug the hole.

TRACKING. Madere stressed that tracking rodents requires paying close attention to detail. Rats and mice leave behind many clues through odor, urine, droppings and rub marks that help technicians determine their presence, the species of rodent and the best placement for traps or stations.

Rodent odor is often the first clue to reach our senses. Madere suggests getting familiar with the unique scents of roof rats and Norway rats by putting their bedding into jars and using the jars as a training tool. He says this technique is effective for cockroaches and bed bugs too; he often will know the pest he is dealing with by walking into a room and taking a whiff.

Rodent species also can be narrowed down by taking a closer look at the shape of the droppings. Norway rats have droppings the size of raisins; roof rats are smaller and have a distinct hook. Even smaller — about the size of rice — are house mouse droppings, which are characterized by hairs that can be seen using a hand lens.

Wherever they go, rodents mark their routes with droppings, urine and rub marks (sebum) as evidence. Before placing traps along these routes, knowing if the route is still in use can save technicians time and frustration. One trick Madere finds useful is leaving his own mark by scratching into sebum rub marks. If the scratches are rubbed over a week or two later, he knows rats are still using the run. He also appreciates advancements in products like monitoring blocks that give droppings a fluorescent color, alerting him to fresh droppings. Non-toxic fluorescent dyes dusted inside rat burrows help Madere understand foraging routes. He also uses different dye colors to detect colonies with shared food sources.

Through experience, Madere says it is not uncommon for species to share paths, contrary to some thinking. He has observed rodents intermingling when the food source is abundant.

“We’ve seen evidence of mice, roof rats and Norway rats in the same area and it even appeared that they were eating in shifts,” he said.

Janet Hurley, Bugwood.org

Another rodent behavior technicians expect to see sometimes is for rats to generally travel along lines, shadows and walls. Madere cautions trackers to watch for exceptions. Studying rodent urine trails identifies places where rats are coming away from the wall, perhaps to avoid a gap or for no obvious reason. In those situations, it may not make sense to follow traditional best practices of placing equipment against the wall. Moving traps or stations into the path away from the wall may be the best strategy for getting contact with the rat.

Tracking rodent trails through dust and sand can literally mean following their tracks. A close look at prints in the dust can point in the direction the rodents are traveling, the route they are following and where to continue your tracking efforts. When he can, Madere shows footprints to customers and points out the telltale outline of four toes on the front feet and five toes on the back feet.

Once rodents have been thoroughly tracked, information gathered about their habits and travel patterns can be used to develop a strategy for trapping.

TRAP PLACEMENT TIPS. Why wait for a rat to discover the trap when success can be achieved faster by bringing the trap to the rat? Using observation skills or technology such as video or sensors, PMPs can locate lines, shadows and other paths rats use to move around an account. It may take creativity to find ways of placing traps in their route. If rats are climbing on a roof to feed on pigeons, try attaching traps to tree trunks. Modern plastic traps or classic wooden Victor traps can be anchored to pipes or beams in almost any angle or direction using zip-ties.

Another effective placement technique leverages rats’ instinct to run and follow the trail of pheromones left by other rats. Madere sets traps perpendicular across runs to catch rats as they run by. Their body passes over the trigger mechanism to be caught by the bar rather than just a head or foot when they are stopped reaching for the bait to feed.

PREBAITING. “If you’re not doing prebaiting, then you’re not doing trapping right,” Madere said. He explained that investing a few nights of prebaiting before active trapping dramatically improves catch results. “Otherwise you’re only pulling out one or two animals at a time.”

Rodents are weary of new food and objects, a behavior called neophobia, causing them to shy away from traps initially. Prebaiting is a way of overcoming neophobia by rewarding rodents with food. Madere makes note of what rodents are eating at the account and prebaits using the food they prefer. He offers eight tips to ensure a successful prebaiting strategy:

1. Eliminate or at least limit all other food sources.
2. Use four to five kinds of bait. If you plan to use 100 traps, try 25 traps of peanut butter, 25 traps with apples, 25 with tuna fish and 25 with dog food or beef jerky.
3. Be generous with the amount of bait to feed as many rodents as possible.4. Add additional traps in areas with a lot of feeding.
4. Narrow the choices to the best performing baits.
5. Don’t limit the bait to just one choice for the rats. Expect a picky eater to be in the bunch. Chances are that picky eater may be a pregnant female or dominant male and you don’t want to miss trapping the rat that continues to reproduce.
6. Don’t forget to empty and rebait the traps with fresh food.
7. Plan to prebait traps for three to four days. Madere continues prebaiting until 75 percent of the traps are cleaned out.

When it’s time to start active trapping, use the opposite approach with bait. Madere recommends loading up the trap with generous amounts of bait when prebaiting. For active trapping, use a small dab of bait placed at the back of the trip plate. The scent of the bait will attract the rat but because it’s only a small dab, the rat will need to lean far into the trap to reach it. The less food on the trap, the more the rodent has to interact with the trigger mechanism, he says. slow and steady wins. Madere says applying technology in rodent tracking and trapping strategies may not solve problems faster, but it does provide notable benefits.

Technology enables technicians to continue monitoring for activity, even when they are servicing other accounts. Cameras and sensors capture activity for review at a later date, often in less time than it takes to observe the activity firsthand. In just one photo, Madere identified the species of rat, the pipe it was climbing to the ceiling, and the exclusion work necessary to close the hole and prevent the rat from entering the room again.

“I can’t be in the alley or in a kitchen 24 hours a day so these things are helping me put forth less effort but still do a better job,” Madere said.

Technology also helps technicians see rodents that may be difficult to find with the naked eye. There are some infrared cameras that attach to mobile phones and an app helps technicians see hot and cold spots, like rodents running through ground cover in landscaping. This is particularly useful at night when they are the most active.

Wikimedia

“This will help you follow the rodent back to where they’re entering and exiting so you know where to focus exclusion work and where to place your traps, sensors or cameras,” Madere said.

Like traps and bait stations, cameras and sensors require planning to be effective. Using good tracking skills to identify where rodent activity is occurring is key to using cameras and sensors effectively. They need to be installed in the right location and PMPs should expect that it may take some practice.

Madere learned enough that he shifted his approach to using cameras before putting out traps or stations. The cameras provide information he didn’t have access to before through observation. When evidence points to active rodent activity, the cameras sometimes tell a different story.

“We are putting out cameras before anything else so we know exactly where our hot spots are. Droppings are not going to tell you how long they’ve been there or if this is still an active trail. Maybe the food source was taken away or the water source went away. Maybe they just decided to quit walking in that direction. Everything told us rats were there but once we put cameras on watch for a few weeks, we saw the threat never traveled that way anymore.”

Another technology benefit is the ability to provide concrete evidence that a rodent program will be or was effective. As a selling tool, prospective customers may be more willing to buy knowing you have technology tools to validate the service. After the sale and after the infestation is resolved, even the most experienced technician may have trouble convincing a customer their approach worked to end the rodent infestation. Video or data collected by sensors showing the absence of activity can be an effective means of providing proof.

FINAL THOUGHTS. Training technicians to be keen observers during trapping can help them investigate small details and be more efficient managing their routes. “We’re looking for trifle things other people would overlook, such as a red drop of blood,” he said.

Madere shared the story of finding a drop of blood on a trap. Knowing the rat was injured prompted the technician to look around the trap area and find the dead rodent, avoiding a return trip back to the account later. Finding whiskers caught in a trap or glueboard also can signal trouble. If the whiskers go unnoticed, the technician may not understand why the trap isn’t getting activity or think to start over with prebaiting to coax the rodents back.

Carrie Thibodeaux is a Tacoma, Wash.-based freelance author who has been writing about the pest management industry for 20 years.