The first-ever open field-release of a self-limiting genetically engineered
diamondback moth has been reported as a success. The new strain of
diamondback moth developed by Oxitec Ltd. is modified to control its pest
counterparts in the field. The Cornell University study led by Professor
Anthony Shelton showed the engineered strain had similar field behaviors to
unmodified diamondback moths, with results offering promise for future
protection of farmers' brassica crops.
After their release, males of the modified strain find and mate with pest
females, but the self-limiting gene passed to offspring prevents female
caterpillars from surviving. With sustained releases, the pest population is
suppressed in a targeted, ecologically sustainable way. After releases stop,
the self-limiting insects decline and disappear from the environment within
a few generations.
Professor Shelton's team used field and laboratory testing, as well as
mathematical modeling to gather relevant information on genetically
engineered strain of diamondback moth, whose wild counterparts cause
billions of dollars in damage. The study was the first in the world to
release self-limiting agricultural insects into an open field.
The field test builds on previously published work in greenhouses by
Professor Shelton and colleagues that showed sustained releases of the
self-limiting strain effectively suppressed the pest population and
prevented resistance developing to an insecticide. "Our research builds on
the sterile insect technique for managing insects that was developed back in
the 1950s and celebrated by Rachel Carson in her book, Silent Spring,"
reports Professor Shelton. "Using genetic engineering is simply a more
efficient method to get to the same end."