Plagues and humanity

INTEGRATED PEST MANAGEMENT (IPM) is recognized as one of the most solid constructions that emerged in agricultural sciences during the second half of the 20th century. However, the history of IPM dates back to the late 1800s, when ecology was identified as the scientific basis for crop protection (Kogan M., Annu. Rev. Entomol., 1998;43:243-70). This concept, originating and rooted in agricultural sciences, has allowed us to lay the foundations for the design and implementation of gtarelli@chemotecnica.com programs for the professional and comprehensive management of urban and industrial pests and disease vector organisms. Assuming that the agricultural sphere versus the urban and industrial sphere are diametrically opposed, it must be considered that a holistic vision regarding the rational control of organisms harmful to humanity will allow us to be more effective and efficient in the implementation of strategies aimed at control. The origin of pest control, as an activity aimed at eliminating rodents, emerged in the early Middle Ages (500-1100 AD). As time went by, the evolution of chemical control tools empowered human beings, to the point of making us believe the extermination of those species considered pests was feasible. Our essence tells us that we can dominate the world, when in reality we only represent 2.32% of the planet's total biomass. If we wanted to simplify the interpretation of what we are as a whole in terms of insect biomass, we could say that 1 human is equivalent to 200 million insects (M. Dourojeanni, Rev. Entomol. Peruana 45:11-17,2006), or that 1 kilo of human is equivalent to 302 kilos of insects. The proportion that we occupy seems tiny in relation to those organizations that we intend to “control” (graph 1). We are in an unequal “competition” without a doubt. While some flies can lay 200 to 300 eggs in the environment and complete their development cycle between 8 and 12 days, humans usually gestate an embryo in 9 months, reaching (reproductive) maturity at least after 12 years. Closer to our species, the synanthropic rodents, whose females can gestate up to 9 young rabbits in 21 days that will reach sexual maturity after 3 months. Biologically, the big difference in our favor is longevity, a factor that the rest of the species compensate and/or exceed, in number of generations per year. Our species has been on the planet for 315,000 years, while cockroaches have already been on the face of the earth for 250 million years (graph 2). Without entering into philosophical terrain, simply being realistic and applying common sense (not always the most common of senses), we can realize that the annihilation or eradication of any species of organism that precedes us would be a fantasy. The biotic potential that pest organisms manifest is extremely high and is directly related to the number of offspring that each female can generate per cycle, the speed with which they reach maturity and the overlap of generations per year. In many species, mainly those that develop within structures, environmental conditions do not affect the normal development of colonies and the overlap of different cohorts is continuous. These capabilities strongly favor the development of adaptive advantages and the expression of genes that confer resistance to the selective pressure actions that our species can use (e.g., irrational application of pesticides). Needless to say, the definition of a pest is exclusively anthropogenic, which is why man defines what is or is not a pest based on the level of impact that the organism in question causes. In fact, the proportion of arthropods and/or vertebrates that represent real pests for humans occupy a very low proportion that is below 1%. The critical thing about this is that any organism positioned in the remaining 99% could be categorized as a pest if it invaded or damaged facilities, or if it vectored a disease that altered the normal life of our population. In this sense, we have been understanding where to focus our efforts, prioritizing the control of “harmful” organisms when it comes to maintaining food safety or against the transmission of diseases. If we wanted to simplify the process of evolution of practices aimed at the rational and professional management of pests at an urban and industrial level, we could use graph 3. Currently the categorization of service companies responds in part to this evolution. Even today, applicators who base their service on the use of chemical pesticides are called “cucaracheros.” On the other hand, those service providers that have maximized physical pest prevention and control strategies over the use of chemical tools could occupy the category of professional company. Technical training, knowledge regarding the needs and biological aspects of the species, the implementation of hermeticity and exclusion strategies, modifications to the environment or critical processes, the good use of pesticides if necessary and the optimization of time and administration through the implementation of management systems, are some of the substantial differences that top-level companies contemplate today. Clearly the type of service provided is in accordance with the type of client served. The companies that require the highest level of professionalism are usually those that provide services to the food industry, basically because they must comply with international standards in order to guarantee food safety. There are small, highly professional companies and very large, extremely deficient companies and vice versa. The quality of the service has nothing to do with the size of the company, but with the commitment and training of operators, technicians and owners. Humanity continues to grow; the larger the population, the greater the demand for services there will undoubtedly be (graph 4). As the population continues to increase, so will primary production at the agricultural and livestock level, the industrialization of food, the growth of cities and urbanizations towards depopulated areas, the generation of waste and our influence on climate change. At this point we must assume coexistence in time, but not in space, with these organisms. We can always keep them out of our structures, if we do the right thing. There is no spontaneous generation of species, which is why, if we minimize their movement and mechanical introduction, we can prevent them from colonizing unwanted spaces (homes, public buildings, factories, etc.). The airtightness or tightness of the constructions, the quarantine observation/inspection of raw materials and finished products, the management of waste, the implementation of maintenance and cleaning programs in accordance with the processes, the implementation of monitoring elements and the strategic use of formulations that allow minimizing the external pressure of pest species if any, will ensure that our coexistence does not represent an inconvenience for any of the parties. Finally, it's about imposing limits. Our tolerance as a species in inferior conditions should be high in external environments and low inside buildings. In what situations is the challenge greater? When it comes to controlling disease vector organisms. In these cases, especially when it comes to species that develop outdoors (e.g. mosquitoes), the evaluation of population levels / entomological surveillance is key to designing planned and non-reactive control strategies. In this way we will have the possibility of minimizing the spread of diseases and transmitting species. From walls outward, the identification of species, the problems associated with their presence in relation to their level of density, and the implementation of preventive + curative measures, are key to reducing the adverse effects that they could cause us. To conclude, it is important to highlight that PESTS ARE USUALLY A CONSEQUENCE OF A FAVORABLE ENVIRONMENT AND POOR MANAGEMENT OF STRUCTURES.