Adult European corn borer.
Living mulches can increase the habitat for predators of this and other insect
pests. In a recent study, the predators consumed corn borer pupaethe
stage just before adulthood.
Predators of Insect Pests Thrive in "Live"
Mulch By Luis
Pons October 26, 2006
Living mulches help farmers improve soil quality and stave off weeds
and erosion. But they may provide another benefit: habitat for beneficial
predators that feed on destructive insects.
A two-year study by Agricultural Research Service (ARS) and Iowa State University
scientistsdescribed in this month's issue of Environmental
Entomologylent weight to this long-suspected hypothesis. The
research showed that predators killed many more pupae of the costly European
corn borer in fields hosting the living mulches than in mulch-free plots.
Unlike other types of cover crops, living mulches are not eliminated
before planting of the main crop.
Hellmich at the ARS
Insects and Crop Genetics Research Unit in Ames, Iowa, and their
collaborators used separate plantings of alfalfa and of kura clover, a
persistent forage of west Asian origin.
The researchers found increases in the number of predators and in the
number of pupae the predators consumed in plots holding a rotation of corn,
soybean and forage crops.
The predators, mostly carabid ground beetles and arachnids, consumed
pupae used as "sentinel prey"that is, prey placed in the field to measure
Within the living mulches, predatory insects killed 66 percent of the
borer pupae planted in corna 51 percent increase over nonmulched control
plotsand 65 percent of the pupae in soybeans, 13 percent more than in the
Scientists in the Ames unit are conducting similar studies targeting
other insect pests.
Living mulches may not provide sufficient pest suppression when used
alone and often need to be suppressed themselves to prevent competition with
the main crop, according to Prasifka. But they can be an important component of
an integrated pest management program.
Also, studies have shown that using legumes as living mulches may
reduce the need for fertilizer by providing nitrogen to the main crop. It may
also lead to yields equaling or exceeding those produced through conventional
ARS is the U.S. Department of
Agricultures chief scientific research agency.