"The sweet whey only costs 32 cents a pound," says Costa, who gets his donated from a New York-based cheese company, and receives support for his research from the USDA and EPA and other funders.
Whey is a far cheaper growing medium than those available in labs for the many fungi now in use as biological controls in agriculture and forestry.
And the whey serves as a nutritional resource, making each droplet a cozy biological factory for a fungal colony, pumping spores out into the forest long after the spraying teams have gone home.
If their laboratory tests continue to go well, the researchers anticipate starting field trials in 2008.
Their approach looks promising for many other applications of biological control for agriculture and forestry—especially in natural settings with economically low-value plants, like natural forests.
"We're not going to eradicate the adelgid," Costa says. "The best-case scenario for an insect-killing fungi is you inoculate the environment and get disease outbreaks to start cycling. The idea is to reduce the pest population to a level that is manageable, allowing some of the trees to make seeds, grow, and survive."
It's a pressing problem: In Shenandoah National Park most of the famous towering hemlocks are now dead. The adelgid has ravaged parts of Kentucky, North Carolina and the Smoky Mountains. Expanding northward, it has moved through Massachusetts into southern Maine and New Hampshire.
The only natural deterrent to the adelgid seems to be a very cold winter. With global warming, their northward spread seems inevitable. Though not officially recorded yet, "it's