“Pest control” and “pest extermination” are not synonymous, but for many customers, clients and industry outsiders, this distinction is often overlooked. Within the pest management industry, however, pest professionals cannot expect a pest problem to disappear by simply eliminating the current generation of pests. In order to make any lasting changes, professionals need to understand the most effective, efficient and environmentally friendly ways to control pest populations using a variety of techniques that range from prevention to extermination.
At NPMA PestWorld 2013, Dr. Roger Gold, professor and endowed chair for Urban Entomology at Texas A&M University, explained how a holistic understanding of pest control can help all PMPs increase their pest management success with just a few basic concepts. During his session, Gold shared 10 concepts that lay the foundation for successful pest management. Although most pest management professionals receive training on the “how” of pest management, Gold’s key concepts focus on building a comprehensive understanding of the “why.” Only when a pest professional understands why the pest population behaves as it does — responding to specific treatments or stimuli — can he or she begin to effectively manage that pest population.
1. Requisites for Life
All living organisms have needs that must be met in order to survive. For animals, ranging from humans to insects, the most basic needs are food, water, oxygen, shelter or harborage, and the ability to eliminate waste products. It’s important to remember, however, that although all animals have the same basic needs, how they meet these needs may vary. For instance, cockroaches can live off of the sustenance remaining in what would be considered a waste product to humans. For pest management professionals, there are two major takeaways related to this behavior. First, when performing an inspection or determining preventive strategies, technicians must think beyond the human mindset and be aware of the unique ways in which certain pests must meet their own needs. In this mindset, technicians will be better able to recognize what aspects of an environment are attracting the pests. Secondly, said Gold, professionals must then recognize that “all you have to do with these resources is…to remove or to contaminate one of the resources to control a population of animals.” In other words, once the resources have been identified, removing or contaminating the sources of that resource will effectively control or eliminate the pest population.
2. Niche Theory
All animals have a niche or a way they interact with their environment in order to survive. Unlike humans (who have a tendency to adapt their environment to their needs), most insects have adapted to their environments. As a result, explained Gold, “An insect has a very specific place on planet Earth where they have all of the resources they need.”
For pest professionals, this concept builds upon the “requisites for life” as a way to help pinpoint which potential sources are the ones likely sustaining the pest population. “There’s a little law in biology that says, ‘No niche goes unoccupied through time.’ And so if the pests were there once, they will be back if all of the resources are still there. So you have to address where they make their living in terms of the niche,” said Gold.
For instance, in a home, there are many places a pest could consider shelter, but based on that pest’s particular needs and characteristics, one area may be more attractive to the pest than another. “We refer to this niche a different way in professional pest management. We call it ‘conducive conditions,’ and this is an important concept. If there are insects in the environment, they have to have those resources. Your task then is to find a way to eliminate one of those resources and to try to identify and eliminate one of those conducive conditions,” he added.
3. The Definition of a Pest
According to Gold, “the concept of a pest, literally, is any plant or any animal that you or your client consider out of place.” It is, therefore, a broad and ever-changing definition based on a client or professional’s own perceptions. In general, there are three main types of pests. The first, nuisance pests, such as earwigs, cause disturbances or discomfort in the home, but with limited risk. Medical pests, such as many mosquitoes, cause health concerns based on their ability to spread diseases and contaminate environments. Finally, structural pests, such as termites, cause physical damage primarily to shelters; other physical pests can damage food supplies. In order to treat an entire pest population, pest management professionals should be aware of the pest type in order to determine the perceived and actual pest threat.
4. Population Dynamics
When it comes to insects in their homes, “Most of the time, people understand that insects pass through...they can fly in and they can crawl in. But when insects begin to multiply and you begin to have what are called populations, that’s when normally we, or our clients, begin to be concerned,” said Gold. Therefore, population dynamics is an important concept, providing valuable insights about how the insect’s environment affects population growth.
Concepts in Practice
During his session, Dr. Roger Gold provided occasional pest invader examples to highlight how some of his basic concepts for better pest management can help create a more comprehensive understanding of the pest population and how to treat it.
Requisites for Life: “Cockroaches are the archetypical example of survival. The fossil record associated with cockroaches goes back 350 million years and they’ve changed very little in that period of time,” said Gold. Omnivorous, these insects eat a wide array of animal and plant material and their waste products. Due to their omnivorous nature, cockroaches have a tremendous ability to survive if there is a food shortage.
Niche Theory: “Cockroaches are so successful because they have adapted through time…they have a niche that they occupy in that they like to be next to animals, so that they can live in caves on bat guano, which is a waste product; they can live in the rainforests or the jungles; they can live in our homes,” said Gold. Cockroaches are “peridomestic” in that they can thrive around human beings and live on human scraps and waste products. They prefer, given a choice, to hide during the day, conserve their energy and then to forage during the night.
Biology: “Their dorsal are ventrally flattened so that they get into tight spaces. Some cockroaches have well-developed wings and fly, while others of them, like the Oriental cockroach group, have lost their wings. They undergo a simple metamorphosis, which means they have the egg, the nymph and the adult stage. Cockroaches also have developed through time an egg capsule called an ootheca. The eggs are laid by the female while that ootheca is being formed in her body. That ootheca is coated with the equivalent of an exoskeleton. And they put wax layers on it so that it’s basically waterproof and it’s very difficult to get chemicals into that ootheca,” said Gold.
Generation Time: Generation times with cockroaches vary from four months to more than 18 months. The general rule of thumb is that the larger the cockroach, the longer the generation time.
Level of Pest Management: Understanding generation time is critical for something called “Gold’s 20-Generation Rule.” What is Gold’s 20-Generation Rule, named after the educator himself? “We basically determined that if we used the same pesticide through 20 generations of these insects…they developed a resistance to the level that it was detectable and made them difficult to control,” he explained. Furthermore, due to the ootheca around the eggs, “Using new products, we would annihilate the nymph stages which were moving around, and the adults, but about a month later, we would go back and they would have what were called the first instars, the first insects that had just hatched out of the eggs in the ootheca,” he added.
When insects enter or are introduced to an environment, “that population begins to grow rapidly if there are no natural predators, parasites or diseases there,” explained Gold. This expansion only levels off once one of those limiting factors is introduced to the environment or once the population has reached equilibrium between population size and available resources. If uncharacteristic or extreme population growth occurs, pest professionals need to be able to assess an environment to determine why that population has expanded so rapidly.
5. Detection Threshold
When a customer has called a pest professional to inspect or treat for a specific pest, in many situations, this call should be an indicator that the pest population has grown to a level that will require some type of management solution. The reason pest professionals should consider these calls an indicator of a larger pest problem is what Gold calls a “detection threshold.”
“It takes a given number of these smaller organisms to be in a particular space on planet Earth before we begin to sense that they’re there. So really, our goal in pest management is not to kill all of the insects. It’s to keep them at a level where they’re not being perceived or they are not causing damage. And that is called the detection level,” he said.
6. Aesthetic Injury Threshold
Interconnected with the detection threshold is the aesthetic injury threshold. While the detection threshold explains how many of organisms need to be in one environment for that organism to be detected, the aesthetic injury threshold explains the quantity of those pests that the customer must see in order for the pest to be considered problematic.
“If people perceive that there’s a problem, then they’ll respond…and this is a good thing when you’re in our business and you want to help them. The problem with an aesthetic injury level is that it’s a moving target,” said Gold. Some may think, for instance, that multiple cockroaches in their home or apartment are acceptable, while others may feel that action should be taken after the first cockroach appears. In order to manage pests, therefore, successful management strategies will also entail educating the customer on pest risks in order to set customer expectations and increase customer participation in the observation and management process.
Also known as the second law of thermodynamics, at its core, the concept of entropy is “the concept that everything deteriorates through time. In order to keep anything in a steady state, you have to expand resources: time, energy and other resources,” said Gold. In pest control, this concept is crucial to understanding why most pest management services cannot be limited to one-time treatments. Consistent efforts must be made to prevent pests and maintain structural integrity. Homes, yards or other human-populated environments that fall into disrepair have a much larger chance of being overrun by pests. For pest management professionals, educating homeowners on how to maintain their homes in order to reduce pest populations is a key phase of pest prevention.
8. Proper Identification
Taxonomy is the science of classification for organisms, typically through a system known as the levels of taxonomic classification. The levels build from most general to most specific in the following sequence: domain, kingdom, phylum, class, order, family, genus and species. Insects and other pests share the same domain and kingdom with humans and other animals, but separate at their own phylum: arthropod. The number of identified arthropod species is greater than the number of all other animal species combined and, in general, this phylum is characterized by the members having an exoskeleton and jointed legs.
For PMPs, Gold does not argue that a successful technician must be able to identify every species of arthropod, but, instead suggests that professionals should be trained to recognize the most common species in their area and have a basic knowledge of the four main pest arthropod classes. “One of the concerns that we have at the university is that we offer services for free — at no charge in the state of Texas — where we identify hundreds of samples every year and we get a little concerned when some of them are coming in from our industry partners that have confusion between some basic things such as a termite and an ant,” said Gold. Ideally, pest professionals should understand these differences and be able to utilize and recognize basic taxonomic pest classifications in order to properly identify — and therefore treat — pests in the field.
Though there are many additional differences between arthropods, Gold gave advice on how to quickly identify the four most common pest classes. The first class is for insects or Hexapods, “meaning six legs. And so if you look at the number of legs and you count them on the organism, if it has three pair and has one pair of antenna and has wings — one or two pair — that is specifically a hexapod or an insect,” said Gold. Hexapod is the only class that has wings. Next, arachnid is the class for spiders, ticks, mites and scorpions. This group has four pairs of legs and no antennae. Malacostraca are classified by having five or more pair of legs and two pairs of antennae. Finally, chilopods are one of the easiest to identify because this group has one pair of legs per segment of their body.
9. Biological Knowledge
One of the main reasons Gold says PMPs should be able to identify the class of arthropods is not just to identify the pests in the field, but also to understand where, biologically, these pests differ in their life cycle and needs. “(There’s an) old saying: Whenever you want to attack something, you go for the weak link,” said Gold. “So by knowing something about the biology…we can address that.”
For instance, understanding the differences in generation time — how long it takes to go from egg to reproductive adult — between classes can help pest management professionals determine how often to inspect and what types of treatment to use to ensure pests do not build up a resistance to the treatment products. Knowing about population potential — the pest’s capacity to increase its numbers through offspring — will also allow a pest professional to better prepare for the population dynamic and detection level of the pest.
10. The Levels of Pest Management
Finally, once a pest management professional understands all of these pest-related concepts, he or she must also understand how to utilize them and integrate them into the different levels of pest management. What are the levels of pest management?
“In integrated pest management, it’s the pyramid,” said Gold. At the bottom of the pyramid is “prevention,” which includes managing potential resources that could attract pests. If pests have already arrived, the next level of the pyramid is the “cultural and sanitation” stage, which involves altering the environment in order to reduce its attractiveness to the pest.
At this stage, techniques Gold mentioned include:
- Remove clutter and sources of moisture.
- Provide ventilation.
- Remove mulch and promote xeriscaping.
- Use a vacuum cleaner.
If the pest remains, further action may need to be taken at the “physical and mechanical control” stage. In this stage, techniques are utilized to minimize pest movement using barriers, such as caulking holes and setting traps. The next stage of management is often referred to as “biological control” because it utilizes natural control strategies, such as introducing more of the pest’s natural predators into the environment or conserving pre-existing predators. The one drawback to this strategy is that often it is a time- intensive process. “At the top of the pyramid and the last and least used, is the use of pesticides. Pesticides are taking those resources for life…and contaminating that environment, or the food, or in the case of a fumigation — which is a pesticide — we’re substituting the oxygen for a toxic chemical,” explained Gold.
The 10 concepts outlined by Gold are fundamental for pest professionals seeking to increase their success when using Integrated Pest Management solutions. “Pesticides are really a substitute for labor. They’re fast and they’re thorough, but there are expenses associated with them and they will not solve the problem through time. Until you have addressed the conducive conditions — that niche where the pest is making their living — they’ll return,” said Gold.
By learning to understand the basics of why pests live and act the way they do, when customers begin noticing and responding to pest populations, and how to identify specific pests, professional pest managers can then utilize these concepts to determine what type of treatment can effectively, efficiently and sustainably manage each specific pest population.
The author is a PCT contributing writer. Email her at firstname.lastname@example.org.