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Why
is there a need to control noxious weeds? Noxious weeds are plants
that typically invade from other countries, leaving their natural
controls and competitors behind (insects, diseases, grazers, and
climate). The resulting uncontrolled growth of these weeds crowds
out native plants and animals, and causes serious damage to our
environment and present way of life. Five methods are currently
being used to control the spread of invasive noxious weeds. They
are: preventive and cultural (indirect control methods), and chemical,
mechanical, and biological (direct control methods). In most cases,
one form of control is not enough. Control often requires the combined
efforts of two or more "integrated" methods to effectively stop
the spread of weeds.
The control of noxious weeds is a complex battle, with a number
of factors governing the methods that may be used. First, they must
be safe for humans, the environment, and non-target plants and animals
in the area. Second, they must effectively reduce the targeted weed
population. Third, effective control practices depend on the life
cycle of the weed, the location, and the size and density of the
population. Controlling the patch of annual weeds in the vacant
lot next door is very different from treating a 1000 acre perennial
weed population located in the mountains. Fourth, the availability,
or lack of tools and other resources may prevent some control options.
And fifth, what is the desired end result? You can eradicate the
population, reduce the population in size and density, contain them
and prevent them from invading new areas, and/or let the weeds grow
uncontrolled.
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