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Noxious and Nuisance Plant Management Information System
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Many noxious terrestrial and aquatic plants cause serious problems across the
country. Problem plants include the terrestrial species snakeweed, knapweed,
leafy spurge, various thistles, seepwillow, silver leaf nightshade, tansy
ragwort, etc., and the aquatic plants waterhyacinth, waterlettuce, hydrilla,
Eurasian watermilfoil, and water chestnut, among others.
Problems arise mainly because of the growth characteristics of these plants,
which enable them to reach very large population levels relatively rapidly,
thereby displacing and subsequently eliminating native vegetation. This in turn
causes significant impacts to native wildlife including the elimination of
endangered species, disruption of delicate ecosystems by the replacement of
native vegetation, decreases in land use and value, reduction of recreational
uses, hindrance of navigation along waterways, increased water loss, as well as
increases in human health hazards associated with expanding mosquito breeding
habitats. Traditional control procedures mainly involve the use of chemical
applications, but these offer at best only short-term solutions, and their use
is becoming increasingly more environmentally sensitive.
There are now more environmentally acceptable techniques and integrated
procedures for noxious plant control. These techniques involve the use of
biological control agents and offer environmentally acceptable and, in many
cases, long-term answers for weed management. The use of biological control
gained public acceptance as early as 1902 with the release of flower- and
fruit-feeding insects for the control of
Lantana camara. These insects successfully controlled the invasion of
lantana in many areas of Hawaii. Since that time over 190 insects have been
released to manage 86 weed species with over half of these attempts considered
successful. The use of biocontrol for weed management has not been confined to
only the terrestrial environment. Many successes have been achieved in the
aquatic habitat. These have included the release of 12 insect species to control
4 problem aquatic plants since the beginning of the aquatic plant biocontrol
program in 1959. Biological control is rapidly becoming recognized as an
important and viable alternative management strategy for weed control. Since
1987, over 40 insect species have been introduced in the United States for the
control of more than 15 weed species.
Because of the expanding number and complexity of available plant management
techniques, it is becoming increasingly more difficult to obtain pertinent and
current information on their use. This is especially true for biological control
technology, where a varied assemblage of both introduced and native agents are
available for use on selected plant species. Effective use of biocontrol also
requires an in-depth knowledge of the agents, life histories, collection
techniques, and potential impact, as well as a working knowledge of basic
population biology and ecological principles.
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