Whats a good way to stop hungry diamondback moths from nibbling on a
farmers cabbage, broccoli, kale and other cole crops?
Agricultural Research Service scientists
have an answer: give the pests a heaping serving of collard greens.
Entomologist Everett Mitchell, at the ARS Center for Medical, Agricultural and Veterinary Entomology in Gainesville, Fla., says giving the pest collards spoils its appetite for cabbage. The moths cant resist the all-you-can-eat collards when theyre planted completely around cabbage field edges, a strategy called trap cropping that could also work to protect other cole crops.
Invading diamondbacks stop and deposit their eggs on the collards rather
than on adjacent cabbage plants. Diamondback populations continue to re-cycle
in collards as long as plants remain green and continue to grow.
Diamondback moths, named for the diamond-shaped markings on their wings, are
becoming resistant to many chemicals. Spraying pesticides can be costly,
ranging from about$10to $21 an acre for each application,
depending on which pesticides are used. It typically costs growers $80 to $168
per acre or more each season to produce a crop.
Mitchell conducted recent experiments on farms in northeast Florida that
showed the moths prefer to feed on highly fertilized collard plants. He tested
this approach for more than two years. In all cases, he says, damage to cabbage
by diamondback moth larvae was minimal.
This simple, low-tech, cost-effective method also reduces pesticide use.
Cabbage fields surrounded by collards required 75 to 100 percent fewer sprays
to control diamondback moth than fields treated conventionally with pesticides.
An in-depth article on this research appears in the March issue of Agricultural Research magazine.
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