The city of Fredericton is turning to nature to tackle an infestation of gypsy moth caterpillars chomping through the leaves of hardwood trees throughout the city.

The city is hoping a naturally occurring virus being tested by Sylvar Technology will stop the caterpillars in their tracks.

Renee LaPointe is a researcher with the company, which offers baculovirus biopesticide technologies for forest pest control. She says the virus is sprayed onto trees, and is ingested by the caterpillars. The caterpillars then die before they're able to form cocoons.

"People in the city, if they have a large infestation of the insect, they will see some that are flopping about and looking quite ill, and this is how they die," LaPointe said.

It's not a quick fix solution, however, as officials say it will likely take a year or more before the virus has a significant effect on the gypsy moth population. There is also a possibility the moths will develop a resistance to the virus.

Don Murray, a forester with the City of Fredericton, says by the time the virus kicks in, it may be too late to save some of the city's trees.

"Naturally occurring viruses and bacteria will lower the population of gypsy moth, but by the time these viruses catch up to the population of gypsy moth, we've often seen some extensive defoliation," Murray said Wednesday.

LaPointe says the virus is not modified, and is specific to gypsy moths so it shouldn't affect other insects.

Gypsy moths first appeared in Fredericton in the 1980s, and their populations have been increasing ever since. Last year, more than 30,000 fuzzy caterpillars were trapped in the city. The Fredericton Tree Commission says this year's numbers are climbing fast.