Brighteners Shine Light on Control of
Diamondback Moth By
November 29, 2002
A possible new aid to beating back diamondback moths is being
tested by Agricultural Research Service
scientists. The diamondback moth is a world-wide pest of cruciferous crops such
as cabbage, turnip and broccoli, and causes about $1 billion a year in crop
losses and pest control costs.
The scientists are using naturally occurring viruses as a new
approach for helping to control these pests. But the viruses act slowly, and
the moth caterpillar can inflict a great deal of damage before it dies.
Fluorescent brighteners, when used with moth-infecting viruses,
can enhance the potency of the virus. Fluorescent brighteners are chemicals
that take in ultraviolet light and re-emit the energy as visible light. They
are commonly used in laundry detergents to make clothes seem brighter.
Research entomologists Martin Shapiro and Robert Farrar of ARS'
Insect Biocontrol Laboratory in
Beltsville, Md., have been testing a newly discovered nucleopolyhedrovirus of
diamondback moth. They found the addition of certain fluorescent brighteners
can make the virus more effective against the insect. The new virus was
discovered by A.H. McIntosh and C.W. Kariuki of ARS'
Biological Control of Insects
Research Laboratory in Columbia, Mo.
The nucleopolyhedroviruses (NPVs) now under study are naturally
occurring viruses, each of which infects only a few insect species. The viruses
are promising alternatives to pesticides for many important pests, especially
caterpillars. While some NPVs have been known to infect the diamondback moth,
none was particularly potent against it. In lab tests, the fluorescent
brightener made the virus four times more effective against the moth
Non-chemical controls are increasingly important because many
insects, including the diamondback moth, are becoming resistant to many
chemical and microbial insecticides.
Alternative control tactics, such as naturally occurring
viruses, can reduce the use of chemical pesticides and problems of
contamination, insecticide resistance, worker exposure and residues in food.
ARS is the U.S. Department of
Agriculture's chief scientific research agency.