Frankfort, Kentucky
February 17, 2009
Pest numbers reduced, fruit
yields increased using organic methods
As the popularity of organic
produce increases with consumers, growers need more options to
manage pests naturally.
John D. Sedlacek and Gary R. Cline (retired) of the Land Grant
Program at Kentucky State University led a research project
designed to investigate options for reducing the presence of
cucumber beetles. These pests damage crops by eating the roots,
shoots, and flowers, and transmit the bacterial wilt pathogen.
The study, published in the
American Society of Horticultural Science journal
HortTechnology, compares several practices in watermelon and
muskmelon crops.
In 2002, watermelon was grown on black plastic mulch with the
exception of one group, which was grown on Al-plastic, an
aluminum coated plastic mulch previously linked to reduced
cucumber beetle densities on squash. Another plot of watermelons
was planted with companion plants thought to repel cucumber
beetles. A third group was planted with a different set of
companion plants that seem to attract insects that prey on
cucumber beetles. Sticky traps stationed among the plants
collected cucumber beetles, which were counted and removed on a
weekly basis. The watermelon yields were not adversely affected
by the Al-plastic nor by the companion plants.
More beetles were collected in the control and Al-plastic groups
than the companion plant groups. Similar numbers of beetles were
trapped in repellent plant groups and beneficial
insect-attracting plant groups, suggesting these plants may be
more valuable as a physical barrier to the beetles' movement
than for their attractive or repellent properties.
In 2003, the study was replicated using muskmelons. Al-plastic
was included again, but the companion plant groups were combined
to include beetle-repelling radishes and
predator-insect-attracting buckwheat. Other treatments included
use of rowcovers and the organic insecticide PyGanic®. The
separate Al-plastic and companion plant groups increased
muskmelon yields of 75% and 66%, respectively, compared to the
control. Rowcovers also significantly increased yield. The
number of trapped beetles was significantly higher in the
control group than in any other.
Then, in 2004, the study was repeated, but this time the
insecticide group was replaced by a combination of Al-plastic
and companion plants. Muskmelon weights varied significantly
among all groups, with the greatest weights coming from the
Al-plastic and companion plant combined groups with rowcovers.
Weights in the Al-plastic-only group were greater than in the
companion plant-only group.
All of the treatments, except for the insecticide, significantly
increased yields compared to control groups. It appeared that
some treatments, such as companion plants, may have reduced
beetle populations by affecting adults, while others, such as
the Al-plastic, may have affected beetle larvae still in the
soil.
The complete study and abstract are available on the ASHS
HortTechnology electronic journal web site:
http://horttech.ashspublications.org/cgi/content/abstract/18/3/436
Founded in 1903, the American Society for Horticultural
Science (ASHS) is the largest organization dedicated to
advancing all facets of horticultural research, education, and
application. More information at
www.ashs.org |
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