When pests become genetically adapted to pesticide and are no longer affected by its use, the condition is known as pesticide resistance. Studies indicate that more than 500 species of pests have developed a resistance to pesticides. The situation is often caused from the same classes of pesticides being used repeatedly over a significant length of time; the pests gradually build up a tolerance that works its way into their genetic structures.
Genetic composition is the key to pesticide resistance. When a pesticide is dispensed over a tract of land, it is only natural that some pests will be killed and some will survive. The survivors then reproduce — and pests tend to reproduce at extremely high rates — resulting in offspring that share the same genetic makeup as their progenitors. With each successive generation of offspring, this genetic composition will only become enhanced, eventually leading to whole species developing the knack of pest adaptation.
The problem of pesticide resistance is a tremendously troubling one to those who work in the field of pest management. A natural response is to use greater amounts of the pesticide in hopes of killing off the lingering pests. This, however, has been shown to be a highly ineffective route, as additional pesticides of the same class just help the pests develop stronger and stronger resistances.
Makers of pesticides define pesticide resistance in a slightly different — but important — way. The industry does not call it pesticide resistance, for one; they have termed it field resistance. In field resistance, the ability of pests to adapt to a pesticide is related only to the failure of the pesticide being used. What the industry is essentially saying is that if a better product had been used, the pests would not have developed a resistance.
There are several species that have become resistant to various types of pesticides. Certain fruit flies in the United States have cultivated a resistance to the pesticide malathion. In the United Kingdom, some kinds of rats have adapted to rat poison and can ingest larger and larger amounts with no effect. The Colorado potato beetle has built up an extremely high tolerance to certain pesticides: studies show that the hardy insects are resistant to more than 50 types.
To battle pesticide resistance, experts suggest utilizing another class of pesticides. Research has emerged, however, stating that this may be difficult since pesticides used in rotation are becoming harder and harder to come by. For the short term, however, a new class of pesticide can likely make a small amount of headway in managing pests.