Genetically Engineered Insects May Save the Florida Orange

November 20, 2008 01:30 PM
by Isabel Cowles
Predatory insects grown in a lab may be introduced to Florida orange groves to save citrus trees from “greening disease.”

Lab-Grown Predators To the Rescue

The disease that has been ravaging Florida’s orange groves may soon be put to an end by genetically engineered predators.

The Asian Citrix Psyllid has spread the devastating “greening disease” across Florida citrus groves since its accidental introduction to the United States less than a decade ago. Native to Pakistan and India, the insect has no natural predators in its new environment.

According to Forbes, more than 6,500 invasive species like the Asian Citrix Psyllid have established themselves in the United States, costing American farmers roughly $130 billion in annual losses.

The Asian Citrix Psyllid thrives on the young leaves of citrus plants, spreading a virus that attacks citrus trees by obstructing nutrient flow, causing fruits to remain green and bitter. Infected trees die of “greening disease” within a few years.

The New York Times reports that infected trees often do not show symptoms for months or years, although they may be contagious. Developing tools for early detection will be essential in stopping the spread of the disease.

But scientists have taken even more aggressive measures to halt its spread. To control the Asian Citrix Psyllid and other invasive species, the U.S. Department of Agriculture's Animal and Plant Health Inspection Service has said it would allow the introduction of genetically engineered predators, or transgenic insects, which would feed on pests without disrupting other species.

Mark Hoddle, a professor of entomology at the University of California, Riverside, believes that genetically engineered predators are a safe solution. "Almost all biological control processes use natural enemies that are highly screened for post-specificity, meaning they feed exclusively on the pests you want to eradicate," he told Forbes. "Genetic engineering allows you to enhance this trait significantly so that the engineered insects eat the desired species and then starve themselves to death."

Not everyone agrees with Hoddle, however. Bill Freese, a science policy adviser at the Center for Food Safety, fears the unforeseen. "This is all experimental stuff and there is a high risk of unintended consequences," he told Forbes.

Reference: The USDA on transgenic insects

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