Gaining Strides Against a Giant Reed
July 16, 2007
The tenacious and aggressive weed known
as Arundo donax, also called Carrizo cane and giant reed, can easily
grow three to seven inches a day and reach a height of 30 feet. Its such
a pernicious nuisance that it is now the top target for entomologist
Goolsby, who works at the Agricultural Research Service (ARS)
Insects Research Laboratory in Weslaco, Texas.
Brought to North America in the 1600s from Mediterranean Europe, A.
donax found many practical uses, including as baskets, roof thatching and
fine-quality reeds for musical instruments. But its negative aspects have far
outnumbered any positive traits.
For example, giant reed invades riparian habitats and irrigation canals,
leading to loss of biodiversity, catastrophic stream bank erosion, and damage
to bridges. It also necessitates costly chemical and mechanical controls along
waterways, and it competes for water in arid regions. Arundo has been
cited as a troublesome invasive weed in Kentucky, Virginia and other eastern
states, the American Southwest, northern Mexico and the Rio Grande Valley.
Taking a high-tech approach to control, Goolsby and collaborators
Everitt, a rangeland scientist, and agricultural engineer
Yang are using remote sensing to delineate Arundos
distribution and density along the Rio Grande and its tributaries. Working with
Texas A&M University scientists, the
Weslaco specialists are assessing how much water Arundo actually uses.
But the best option for long-term management of the weed may be biological
control using insects from the native range of A. donax. So far, three
insectscaptured and identified by scientists at the
ARS European Biological Control
Laboratory in Montpellier, Franceseem the most promising candidates.
Tetramesa romana, a wasp thats harmless to humans and animals,
feeds on new Arundo shoots and canes, while the wormlike larvae of
Cryptonevra flies prefer to stick to the tightly-compacted new shoots.
The flat-bodied scale insect known as Rhizaspidiotus donacis favors
Arundo roots and tubers.
more about research on this and other invasive weeds in the July 2007 issue
of Agricultural Research magazine.
ARS is the U.S. Department of
Agricultures chief scientific research agency.