If you use a pest control measure, you have to be on the lookout for the development of pest resistance. Nobody can ignore this problem
Definitions
Resistance involves inherited (genetic) physiological and/or behavioral adaptations that confer a selective advantage in the presence of a pesticide and that lead to control failures. Cross-resistance occurs when resistance to one insecticide confers resistance to another insecticide, even where the insect has not been exposed to the latter product. Tolerance is when physiological and/or behavioral adaptations lead to increased survivorship relative to some toxicity baseline (not genetic). Mode of action is the specific physiological activity of a toxin that results in the death of a pest.
Resistance Development
Resistance development is affected by the frequency of application rate or dose of pesticide, and certain pest characteristics. Some arthropods are more likely to develop resistance to pesticides than others. Arthropods like mites, aphids, whiteflies, and thrips have similar traits that contribute to resistance development, such as having many generations per year, exposure of multiple generations to a pesticide, having a lot of offspring, limited dispersal, and exposure to sublethal (less than optimal) pesticide doses.
The pests within a population often vary in their level of susceptibility to a pesticide. But before exposure to a new pesticide, resistant individuals are rare. After an application, the more susceptible pests die and the less susceptible ones survive, mate with other survivors, and reproduce. Most of their offspring then inherit the parental trait that allowed them to survive the pesticide application. Further applications kill the most susceptible individuals, so the survivors mate and produce more similar offspring. Continued applications within one chemical class or mode of action further select the population until the resistant genotype is the most abundant or dominant. Pure resistance in a population is probably not present before product failures begin.
Functionally, pest populations may become insensitive to formerly effective pesticides through one or more means. For example, resistant pests may deactivate (break down), sequester (safely store within their bodies), avoid or excrete the toxin from their bodies more effectively, have an altered target site in the nervous system that will not respond to the toxin, or reduce the permeability of their exoskeletons (“shells”) to the toxin.
Resistance Management
The best solution to pesticide resistance development is to diversify protection techniques and not rely solely on pesticides. To maximize product efficacy, follow the label instructions and consider these tips. Use fresh, fully potent pesticides that are prepared and applied according to label directions.
We try to delay or reverse resistance by avoiding use of the pesticide, mode of action, or chemical class for some time. The hope is that the resistant pest populations may lose their resistance traits and become susceptible in the absence of repeated exposure. However, if those pesticides are used again, resistance may return. The market life of key pesticides may be extended using several strategies, which include mixtures, rotations, and mosaics (Hoy 1999).
Cases of pest resistance to popular pesticides increase control costs, the frequency of pesticide applications, the desire to use “fringe” or illegal methods of control, exposure of people and animals to toxins, and likely the amount of regulation needed to keep the environment safe. Implementing resistance management (e.g., integrated pest management) practices will help keep current products on the market longer
Adapted from
Buss, E. A., Price, J. F., McCord, E., & Nagle, C. (2009). Managing Insecticide and Miticide Resistance in Florida Landscapes.
***********************************************
The BEE-L mailing list is powered by L-Soft's renowned
LISTSERV(R) list management software. For more information, go to:
http://www.lsoft.com/LISTSERV-powered.html
|
