Fungal Control for Root-Eating Insects
August 9, 2007
Root-eating insects could soon be
eating themselves sickif their favorite food has been treated with a
fungal biocontrol agent.
Agricultural Research Service (ARS)
scientists in Corvallis, Ore., are discovering new ways to use fungal spores
for controlling the black vine weevil and other root-eating nursery pests.
Many biological control agents are expensive and ineffective against
root-eating larvae. However, entomopathogenic fungithose that cause
diseases in insectshave proved successful.
Current control methods involve applying large amounts of entomopathogenic
fungi to the soil in which at-risk plants grow. This approach is both costly
and inefficient. ARS entomologist
Bruck has discovered that using plant roots as an underground
"delivery system" for the fungi is cheaper and more effective than
He and his colleagues in the Corvallis-based
Horticultural Crops Research Unit tested several fungal strains and found
that some of them thrived in the area immediately surrounding a plant's roots.
In fact, some fungal populations were 10 times denser there than in the
surrounding bulk soil.
In one study, Bruck and his colleagues dipped plant roots in solutions
containing spores of Metarhizium anisopliae, a fungus that occurs
naturally in fields but not in container-grown plants. They observed that black
vine weevil larvae died after eating the fungus-treated roots.
Dipping roots in entomopathogenic fungal solutions may prove to be
economical and efficient, because growers would only need to treat that
Another study demonstrated that black vine weevil larvae actually prefer the
colonized plant roots, so they are more likely to snack on roots that will harm
them. Perfecting a fungal solution to root-eating pests could potentially save
the West Coast nursery industry millions of dollars every year.
more about the research in the August 2007 issue of Agricultural
ARS is the U.S. Department of
Agriculture's chief scientific research agency.