An Innovative Way to Combat Pests

By Ed Martinez

July 6, 2009

According to the U.S. Department of Agriculture, damage caused by termites and other pests is estimated at more than $41 billion per year. Up to this point, the only effective way to combat these insects has been through the use of synthetic organic chemicals; otherwise known as chemical pesticides.

"When you look at the chemical pesticides now used, they're harmful not only for insects but also for humans too," said MIT Professor Ram Sasisekharan, director of the Harvard-MIT Division of Health Sciences and Technology. Sasisekharan is leading a team of researchers that have discovered an innovative way to defeat pest insects by making them more susceptible to bacterial and fungal infections. This is accomplished by blocking part of their immune defenses. The findings may lead to the development of new pesticides that pose a far lesser threat to human health than the chemical pesticides that are in use today.

Sasisekharan’s research focused on specific proteins, known as gram-negative bacteria binding proteins (GNBPs). These GNBP protect certain types of insect species such as termites, locusts and cockroaches, against pathogenic bacteria and fungus. They do this by a process in which they break up the harmful bacteria and expose the parts to insects, which then prepares the immune system response.

When the researchers discovered this process, they decided to attempt to block the proteins using termites in laboratory tests. They found that a sugar called GDL (glucono delta-lactone), a naturally occurring derivative of glucose, inhibits the GNBPs and makes the insects more prone to infection. After only a few days of being exposed to GDL, all termites died from pathogenic infections. A second group of termites not exposed to GDL lived twice as long.

GDL has been proven to be harmless to beneficial insects, as well as other animals and plants. It is prepared via a fermentation process from corn, and is commonly used as a substitute for enzymes in cheese processing and tofu manufacturing. It is also biodegradable and inexpensive, which make it an attractive alternative to chemical pesticides.

Sasisekharan is not alone in finding new ways to combat pests. Biologists are working on developing virus-based pesticides that are only harmful to insects. Unfortunately, virus-based pesticides been tried before and were found to be too expensive and not effective against multiple insect species.

The MIT research team hopes that the compound can be incorporated into building materials, perhaps even paint to protect buildings from termites, or made into a spray that can be used in fields where pests need to be controlled. There is no doubt that Sasisekharan and his team are laying the groundwork for a new and more eco-friendly alternative to chemical pesticides.