Agriculture Reference
In-Depth Information
Soon afterwards, kudzu became valued for the fragrant purple flowers and the
large hairy leaves that provided dense shade for an arbor or a screen for a fence.
Later, kudzu was grown in the southern United States as a forage crop to reduce
erosion and improve the soil. In 1935, the Soil Conservation Service began
using kudzu as a soil binder to prevent erosion on roadside slopes and farm-
lands. At one time, the federal government paid as much as $20 per hectare for
farmers to plant kudzu. Kudzu clubs were even formed to promote its use,
including the 20,000 member Kudzu Club of America. The founder of the club
christened kudzu the “miracle vine”. Communities were holding kudzu festivals
and crowning kudzu queens. By 1946, kudzu had been established on 1,215,000
hectares of highly erodible land across the South. By 1955, kudzu had escaped
from its original planting sites and covered trees, shrubs, gardens, fences, power
lines, and almost anything that stood in its path. Kudzu was listed as a common
weed by the US Department of Agriculture in 1970 [26]. Today, kudzu is wide-
spread throughout the Southeast and covers large areas with impenetrable thick-
ets. In 1988, over 2.8 million hectares of land was infested with Kudzu. The
plant poses a serious threat to timberland, because its dense foliage blocks
received sunlight.
Economic impacts of invasive plant species
Many of the non-native plants have great economic importance in agriculture,
forestry, horticulture and other agricultural industries and pose little or no
threat to our ecosystems, while others have become invasive over a period of
time. In a 1993 report of the Congressional Office of Technology Assessment,
the cost to taxpayers of introduced species in the US was estimated to range
from hundreds of millions through billions of dollars in each year [10]. A
recent assessment in 2000 calculates the annual loss by alien invasive species
to be of $336 billion in six major countries, including the United States ($137
billion), South Africa ($7 billion), United Kingdom ($12 billion), Brazil ($50
billion), and India ($117 billion) [3].
About a quarter of the USA's agricultural gross national product is estimat-
ed to be lost each year to foreign plant pests and the cost of controlling them.
In the western United States, jointed goatgrass (
Aegilops cylindrica
Host),
non-native species, now infests 2 million hectares of winter wheat and addi-
tional 2 million hectare of fallow land. It is spreading unchecked at a rate of
20,000 hectares or more per year. Currently, jointed goatgrass costs US farm-
ers $45 million annually in direct yield losses and reduced grain yield. The
indirect costs of jointed goatgrass exceed $90 million annually, and total loss-
es exceed $145 million annually [27]. Jointed goatgrass is one of “The Least
Wanted” alien or non-native species in the United States.
Leafy spurge, a deep rooted perennial, grows upwards of 1 m in dense
patches and now infests about 1,093,500 hectares, mostly in southern Canada,
and the Northern Great Plains of the United States. This highly competitive
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