Study Behavior of Leading Stored Grain Pest
By Jim Core
May 7, 2003
Safer alternatives to protect stored food
products from the Indianmeal moth and its larvae are being sought by
Agricultural Research Service scientists
at the agency's Center for Medical, Agricultural and Veterinary Entomology (CMAVE) in Gainesville, Fla.
Scientists in CMAVE's
and Bioregulation Research Unit want to find alternatives that eliminate or
reduce conventional pesticides and that also make sense economically. Studies
have focused mainly on protecting processed cereal-grain products by using the
infesting moths' own behavioral and physiological responses against them.
Cereal products become infested when females lay hundreds of eggs directly
on the product or when newly hatched larvae crawl into the product. For a
successful infestation, a cereal must have the appropriate nutrients for larval
growth. According to research chemist Don Silhacek, the growth rate of
Indianmeal moth larvae can vary widely, depending upon the product's nutritive
and physical qualities. Scientists are identifying the nutritive factors
naturally limiting moth development on some commercial cereal products. Their
goal is to design products that appeal to people and animals but aren't
susceptible to moth infestation.
A second approach is to limit or eliminate pesticide use by gaining a better
understanding of juvenile hormone (JH) regulation of moth development. JH first
appears late in embryogenesis and is maintained at high levels during the
larval stage, preventing metamorphosis into an adult. Silhacek achieved
effective control of moths in cereal products in model warehouses using
strategically placed applications of pyriproxyfen, which interrupted
embryogenesis and prevented the pests' eggs from hatching.
In another approach, two model warehouses with controlled environments are
being used to identify external factors affecting moths' behavioral and
physiological responses during cereal product infestation. Researchers are
investigating whether moth behavior can be regulated by modifying the warehouse
photoperiod (the light/dark cycle) and by substituting different wavelengths of
light into it.
Read more about this in the
May issue of
Agricultural Research magazine.
ARS is the U.S. Department of
Agriculture's chief scientific research agency.