Researchers from the United States have set the insect world abuzz with news the first successful release of genetically engineered moths has occurred.
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Designed to reduce pest populations, the engineered male diamondback moths mate with females of the species as normal, but pass on a self-limiting gene to their female off-spring, meaning the caterpillars do not survive to damage crops or grow into moths themselves.
A serious pest of brassica crops, such as canola, cauliflower and cabbages, researchers claim the technology will significantly reduce population numbers of the agricultural pest, slashing insecticide use.
Developed by Oxitec Ltd, a British subsidiary of US biotechnology company Intrexon, the engineered moths were recently part of a Cornell University research trial, led by Professor Anthony Shelton.
Prof Shelton said the field research built on previously published work conducted in greenhouses and demonstrated sustained releases of the self-limiting strain effectively suppressed the pest population and prevented resistance developing to an insecticide, a win-win situation for pest control.
"Our research builds on the sterile insect technique for managing insects that was developed back in the 1950s," he said.
"Using genetic engineering is simply a more efficient method to get to the same end."
Prof Shelton said the study was the first in the world to release self-limiting agricultural insects into an open field.
"For the field study, we used the mark-release-recapture method, which has been used for decades to study insect movement in fields," he said.
"Each strain was dusted with a fluorescent powder to mark each group before release, then captured in pheromone traps and identified by the powder colour and a molecular marker in the engineered strain."
Prof Shelton said his team were very pleased with the results of the study, which showed the technology could be viably used in field crops and reduce the use of insecticides.
"When released into a field, the self-limiting male insects behaved similarly to their non-modified counterparts in terms of factors that are relevant to their future application in crop protection, such as survival and distance travelled. In laboratory studies they competed equally well for female mates," he said.
"Our mathematical models indicate that releasing the self-limiting strain would control a pest population without the use of supplementary insecticides, as was demonstrated in our greenhouse studies."
Oxitec agricultural lead Dr Neil Morrison said the genetically engineered moths were a win for growers and the environment.
"This study demonstrates the immense potential of this exciting technology as a highly effective pest management tool, which can protect crops in an environmentally sustainable way and is self-limiting in the environment," he said.
Dr Morrison said after releases of the genetically engineered moths stopped, the self-limiting insect population declined and disappeared from the environment within a few generations.
Oxitec estimate the global cost of the diamondback moth to agricultural production is between $4-5 billion, with that cost likely to rise as incidence of insecticide resistance continues to increase.
