[Green Pest Management] A Day Without Pesticides

Features - Green Pest Management

How do you treat sensitive accounts that require no pesticide use? Here’s a hint: inspections and exclusion techniques top the list.

March 20, 2014
Dr. Kathy Heinsohn

Author’s note: This article is excerpted and condensed from what was originally given as a presentation at the October 2013 University of Kentucky Short Course Meeting titled “A Day Without Pesticides (Servicing High-Clean and Unique Environments).”

Because of the nature of sensitive and “high-clean” clients, any pest management approaches used in these environments are almost by default going to be green, which that is to say, they will request pest management solutions that use little to no pesticides.

Who are these high-clean or sensitive/unique environment clients that demand these kinds of approaches? These are places where no pests and/or pesticides can be tolerated! Examples are not limited to, but may include the following:

  • animal research holding areas/zoos/aquariums
  • computer facilities/electrical engineering and high-level physics labs/clean rooms
  • museums with ancient artifacts or archives
  • research labs, especially those using insects as research subjects, i.e., fruit flies (D. melanogaster) or mosquitoes or sand flies
  • pharmaceutical and genomic processing plants
  • hospitals and nursing homes
  • food-processing plants (especially those making baby formula)

The PMP who services these sites must be the most competent in the industry. These environments require expertise, are extremely sensitive, and may have hazards to people, animals, artifacts, research findings, food and/or equipment. The PMP should certainly be state certified, but also should maintain additional accreditations as appropriate, such as the BCE or ACE. (See ESA website for information on these at www.entsoc.org.)

Pest management professionals should not be intimidated by these accounts. But, service technicians should think outside of the box. (Which is actually where the future for us is headed, anyway...)

Think Outside the Box.

In our industry, we have been habitually trained to be reactive to pest issues. We typically receive calls from customers and promptly respond. So, what if we were to turn the tables a bit, and be more proactive? I argue a pest is not a pest unless it is where it is unwanted (usually inside the client’s space). If it’s not inside, it’s usually not a pest. So, (and I know this is easier said than done) keep the pests outside. If they do get inside, trap them out secondarily, but don’t let them get inside in the first place.

This is a slightly new pest management technician paradigm for some, but at our company (American Pest, Fulton, Md.) we’ve been doing this for years in most of our sensitive accounts. There’s good money to be made doing so. It just requires a little bit of adjustment in our thinking. And, if anything, preventing pests from entering an account should demand higher dollars than reactively cleaning them out.

I maintain this can be done because I’ve seen it. Caulk and door sweeps are now your new BFFLs (best friends for life) with these more sensitive/high-dollar customers. So we are now going to become door sweep and caulk jockeys, so that the pest doesn’t get inside in the first place.

Products to Use.

Door sweeps and caulk (and other exclusionary, non-pesticide approaches) will be your first barrier to pest entry into these facilities. Secondarily, strategically placed monitors and traps (including insect sticky monitors, glueboards [if allowed], pheromone traps, ILTs, multicatch and snap and rodent traps) will trap those that might get by or hitchhike in on employees and staff. These inside traps should be strategically placed closest to exterior personnel doorways and loading dock receiving areas to identify weak points in your door sweeps and caulking. The monitors become decision-making tools and help you know if your exclusion efforts are being compromised. They are placed where pests will encounter them 24/7 near exterior entry points to the facility. So, the monitors tell you if your door sweeps are working.

(Note: Most of these sensitive facilities do NOT want rodent glueboard traps used for trapping mice or rats, as they maintain it is inhumane and cruel for mice to be trapped and die in this way. Most of these sensitive accounts, which may include zoos or animal research areas, are often supportive of multi-catch traps and sometimes snap traps, which, if set and operating correctly, result in a quick and humane death to the rodent; it is up to the PMP to know how to set these traps properly to work in this manner.)

If It's Not Inside…

Again, remember your new paradigm: If it’s not inside, it’s not a pest. This requires an intense three-dimensional approach to inspection of the entire property and building before the contract is even signed. Identify all possible entry points. Also identify contributing conducive conditions on the exterior. The singular philosophy for both client and the PMP should be: The time and place to fight the pest is before it enters (and certainly before the client notices it).

Your inspection should work from the outside in. Concentrate on four things on the exterior. Look for: 1) resources contributing to pests on the property, 2) types of pests currently present, with a nod to historical and seasonal accounts of pest occurrence, 3) locations of these pests, and 4) most importantly, the building’s footprint and potential routes of entry into the building for these pests.

Recall the three-legged stool of IPM pest needs: food, water and harborage (warmth). Focus your inspection for these contributing items: water sources (i.e. decorative ponds and fountains, standing water); things stored and contributing as harborage sources (i.e., piles of lumber, old equipment, any materials leaning against the building); and food sources (i.e., Dumpsters, recycle bins and trash cans, grease containers). To stress any pest population, removal of any one of these items will help your cause. Of course, the more you remove, the better. The more sterile or barren the buildings’ exterior the better.

The History of ‘Green’

How did the pest management industry get to the place where customers are dictating and demanding that we solve pest issues with few to no pesticides?

There’s a long line of driving forces that have led us to where we find ourselves today. One of the most well-known examples is Rachel Carson’s master’s thesis, that when published in 1962, became the tome “Silent Spring.” In “Silent Spring,” she questioned what the nation was doing to its environment with the indiscriminate use of pesticides, primarily DDT. A decade after her publication, the Environmental Protection Agency was formed in 1972, the beginnings of the environmental awareness movements, and the issuance of a cancellation order for DDT in 1972. Environmental awareness caught on as a movement and grew through the 1970s. (I remember as a child being president of my neighborhood environment awareness group formed in elementary school.)

In the 1980s, a more shocking event propelled the environmental movement and such awareness. In Bhopal India, the Union Carbide plant experienced a methyl isocyanate gas leak in 1984, and more than 500,000 local residents were exposed; unfortunately, more than 16,000 of them fatally.

In the 1990s we saw a move toward the use of more target-specific insecticides like IGRs and gel baits and the rise of the “IPM in schools” movement. The Food Quality Protection Act (FQPA) soon followed, as a concern existed that children were more easily exposed to pesticides than adults, and terms such as “risk cups” became en vogue. EPA findings determined that a child being smaller than an adult could not tolerate the same exposure to a pesticide safely.

The movement seemed to have its roots out West, especially in California, and then take hold and move eastward within the United States. We saw new terms appearing such as Organic, LEED and San Francisco Approved Pesticide List in the 2000s as support increased.

More recently, the issues have jumped the pond from Europe and landed in the United States with the focus on honeybees and the use of neonicitinoids in particular. (This, I find fascinating, since when I’m not at work, I’m a hobbyist beekeeper in my backyard and very involved with the local beekeeping groups.)

We’ve gone from “Silent Spring” to “silent sting,” but in my opinion, such an environmental awareness has challenged us in our industry, and has actually made us better and more targeted in our pest management approaches. Such focus is not necessarily a bad thing.

In our industry, we typically make the recommendation for no plantings against the building and for placement of pea-sized gravel 2 to 3 feet out and 2 to 3 inches deep around the perimeter; this creates a pest-unfriendly zone. However, with these more sensitive accounts, consider making the recommendations greater. How much greater? This will depend on the documented historical and seasonal pest accounts at the facility and the natural surroundings and the cooperation, suggestions and advice of the facility’s management team.

On the interior, the PMP must be familiar with the building’s complete blueprint and flow of materials within it. Your inspection should concentrate especially on all openings: staff doorways, shipping and receiving dock doors, quarantine areas, elevator shafts, trash shoots, eaves, weep holes, siding, pipe and utility conduit penetrations, roof air intake/exhaust ventilation ducts and systems to the outside, etc. These are the areas to target for exclusion with mesh screening, door sweeps, and caulking to exclude potential pests. Most of these high clean/sensitive accounts will tend to be located in newer buildings, built with some pest proofing and high cleanliness in mind; this is to your advantage. However, this is not always the case.

The Importance of Light.

Where possible, use light as a friend to tell you where your openings into the facility and within the facility are located. These are the openings that pests will use to gain entry into the building or into void spaces within it. As other pest management industry speakers have said in the past, a PMP should do a night time light leak audit of the facility to see where light is escaping from the building. And they should also perform a daytime light leak audit. These areas are what should be targeted for pest exclusionary measures.

Door Sweeps.

Every door into the facility from the outside should be outfitted with door sweeps. To exclude pests best, the sweep should be flush with the threshold or the floor, and placed on the side of the door opposite the hinge. Nylon bristle brushes are recommended for exclusion over plastic or rubberized flaps that can easily crack in cold weather and with lots of use; nylon bristles remain flexible to 60°F; the nylon bristles fill out gaps and conform to surface irregularities to close them up. Make sure that the entire space of the gap is covered with bristles.

Fortunately, few tools are needed to install sweeps on doors: a cordless drill and bits, a tape measure, a hacksaw to cut the sweep to size and linesmen pliers; proper installation takes less than 10 minutes. A PMP can (and should) learn to do this easily; (most sweep manufacturers include detailed instructions with the sweep). Just keep in mind that there’s a tendency to cut the sweep too short or to install it too high above the threshold to allow the door to close properly.

Measure twice and cut once with pests in mind. You should see no light coming through the bottom or the edges where the sweeps meet the door frame. Doors that are used frequently may need sweep replacements often; depending on traffic usage, this may mean every six months, or even quarterly. Regular inspections by the PMP and use of a #2 pencil slipped under the sweep will reveal if the sweep is operating properly. If light can be seen coming through below or through the sweep’s bristles, an insect and perhaps even a rodent can enter; the sweep should be adjusted to fit snugly, or replaced if frayed. (Mice require only ¼-inch gaps, and rats require only ½-inch openings. Most insects can get through even smaller gaps.)

For double door entry ways, the gap where the doors meet in the middle must also be outfitted with either a brush sweep or an extended L-shaped bristled door sweep from the bottom of the door, or both. Again, no light should be seen coming through the space. For lobby spaces with two sets of doors (single or double), both inner and outer sets of doors should be outfitted with sweeps to be pest tight. Some facility management teams will argue this point. If so, the outermost door must have the sweep. But, in your arsenal of arguments for keeping the pests out, include the fact that you are also helping them save money by assisting to better heat and cool the space by preventing gaps where air can escape.

Loading dock doors can be a challenge to pest proof. Roll-up doors do not always meet thresholds as they should, or lifts and other dock platform and leveler devices may interfere with good seals. There may be gaps at the top where birds or rodents may nest or enter. Wire mesh hardware cloth can be fashioned to exclude at these top corner edges, so as not to interfere with automated opening mechanisms. Brush sweeps can be installed along the sides and tops of the dock doors. Four-six inch bristle brushes tend to be standard, but be sure to measure the openings between the door and the mounting surface (usually masonry) before ordering your sweeps for install. The roll up doors should still function properly with the sweeps in place.

If a building is pest tight, keep in mind that in sensitive/high-clean accounts, if pests do appear, they are usually in support areas of a facility and hitchhiked in with employees. They will seek food, water and shelter, so you will find them in kitchens, bathrooms, employee desks and lockers and stored feed/food areas.

Alternatively, pests may enter with interior decorative plants. Interestingly, it is my experience that most of the sensitive facilities have a quarantine procedure for new arriving materials, but, rarely do they have a quarantine for decorative plants. Thorough inspections of all items coming into the facility should be a part of your plan.


Every identified opening on the exterior and inside the building into a void area needs to be caulked shut. It is amazing how caulk can disrupt an ant, cockroach or rodent population by keeping them from the food, water and shelter resources they seek; it stresses the population, helping the infestation to subsequently crash. In sensitive accounts, where no pesticides can be used, caulk is helpful. In labs, animal holding rooms and clean rooms, caulk makes detailed cleaning and room sterilization easier for high clean areas by eliminating cracks and crevices where debris could support the growth of harmful bacteria, and potentially pests.

What are these void areas inside that should be considered? Drop ceilings, hollow block walls, attic spaces, power boxes, bumper rails on hallways, corner guard edges, hollow doors, door frames, wall and ceiling mounting plates around items such as water sprinklers, fire exit signs, fire alarms, outlet boxes, switch plates, sensors, window sill framing, baseboards, fire extinguisher boxes, drinking fountains, door hinges and mounts and closing apparatus, etc.

A thorough inspection of the building will usually reveal a long (often overwhelming) list of recommendations where caulking should be done to eliminate every possible harborage space for a potential cockroach, ant or rodent. It is the PMP’s job to sell this to the client as necessary to prevent pest incursions. The more sensitive the account, the more likely the facility management will be on board with your assessment. Keep in mind that like with door sweeps, caulking is not a once and done thing. Repeat inspections will reveal if the caulk is wearing down and needs a touch up. Any openings or areas where caulk is pulling away should be reapplied.

There are many different kinds of caulks out there, so do your research.

When using caulk, consider the following: Is it going to be for indoors or outdoors? How easy is it to apply? To what temperature will it be exposed? To what moisture levels will it be exposed? To what surface will it be applied? And, can it be painted over, once dry?

Caulk used inside a facility will sometimes be abused by repeated power wash downs with corrosive antiviral/antibiotic materials and water in sensitive lab or animal holding areas. So, it will break down and need repeated applications with time.

For interior applications in most sensitive accounts, an acrylic latex silicone blend of caulk seems to be best. (Always check with the facility management team before using and get its approval. There may be sensitive archival materials or animals or research within the facility that would be negatively impacted by the off gassing of such a caulk.) An acrylic latex silicone blend, a hybrid of acrylic, latex, and silicone caulks, is easier to apply than regular silicone caulk, but has similar durability. Some types can be painted to match certain color schemes. And, it is good for both indoor and outdoor uses, including wood siding, cracks in brick and stone, and for weatherproofing windows and doors.

There are certainly a host of other exclusionary measures to consider for building pests out of a building. This discussion has mostly concentrated on door sweeps and caulk. But don’t forget other items you have at your disposal: mortar, stainless steel mesh, hardware cloth, screen, dock leveler brushes, air curtains, bird netting, strips and spikes, and fencing. Think outside of the box and employ what seems best for your situation.

Final Thoughts.


If it’s not inside, it’s usually not a pest!

Keep pests outside!

If it does get inside, trap it!

Become a door sweep and caulk jockey, so it doesn’t get inside!


Kathy Heinsohn, Ph.D., BCE, is a Technical and Training Entomologist with American Pest, Fulton, Md. Email her at kheinsohn@giemedia.com.