A Sickening Solution
i.new IITA
By making cowpea’s most damaging attacker sick with a virus, IITA scientists
may be able to help African farmers harvest much more of this vital,
protein-rich food.
Larvae of a moth called Maruca vitrata are eating up cowpea crops throughout
Africa. They feed on buds, flowers, leaves, and pods—the older ones move the
quickest, feeding continuously and severely damaging the plants. If some of the
pests can be infected with a virus, they will reproduce less and live shorter
lives. Lowering the population of Maruca in cowpea fields would also lower crop
losses, which can reach 80%.
IITA researchers are studying one of Maruca’s natural diseases to find out
whether it will work as an effective biological control against the most serious
constraint on cowpea production in West Africa, where the crop is widely grown
and eaten by millions of people.
“What we’re doing is working to reestablish the balance of nature—letting
the natural enemies do the work of chemical insecticides,” said IITA insect
pathologist, Dr. Andy Cherry.
Farmers who can afford them rely heavily on chemical insecticides to control
Maruca. But these chemicals also kill Maruca’s natural enemies—its predators
and parasites. Using a biological control instead, farmers could zero in on
Maruca, lower the population of this pest in their fields, and avoid the threat
of developing pests resistant to chemical insecticides or harming humans.
IITA scientists are now collecting Maruca larvae from fields in West Africa to
find out whether the virus is naturally controlling the insect. Once they know
how widely the virus occurs in nature, they can look into ways of redistributing
it to areas where it’s less prevalent. With more of this virus and
consequently fewer Maruca in the fields, Africans rather than larvae can eat
more cowpea.
More Information:
I.new, International Institute of Tropical Agriculture, IITA. www.iita.org
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