Pesticide Resistance [top]
Pesticide Resistance is the ability of a life form to develop a
tolerance to a pesticide. Pests (weeds, insects, mites,
diseases, etc.) that become resistant to a pesticide will not be
affected by the pesticide. When pests are resistant, it is more
difficult to control the pest. Therefore, it is important to try
to prevent pesticide resistance.
Sometimes scientists breed pesticide resistance into plants.
These plants will not be affected by that pesticide, and when the
pesticide is used on a resistant crop it does not harm the crop.
For example, roundup ready canola can be treated with roundup to
control weeds. The weeds will die, but the canola is not
affected.
Plants may also be resistant to certain pests. These plants
will not be affected by the pest. Using resistant plants is an
effective control method that should be part of IPM programs.
How Resistance Develops [top]
Resistance usually develops by genetic mutation and
selection. Types of mutations can include: a change in processes
in the pest that make the pesticide harmless, a change in the
place where the pesticide enters the pest so it cannot enter, or
a change in the behavior of the pest so that it avoids the
pesticide. Resistant pests are selected when the pests
reproduce. For example, in any pest population there may be some
pests that will not be killed by the pesticide. When the pests
that survive breed, some of their young will inherit the
pesticide resistance. These pests will not be affected the next
time the pesticide is used. With each generation, the pest
population becomes more difficult to control with the same
pesticide. If the same pesticide is applied often, there will be
more resistant pests than susceptible pests.
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Development of Pesticide Resistance
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