© 2024 Milwaukee Public Media is a service of UW-Milwaukee's College of Letters & Science
Play Live Radio
Next Up:
0:00 0:00
Available On Air Stations

Biologist Attacks Pests with Environmentally Safe Control Agents

R. Rothman NYS Museum

Daniel P. Molloy took on “out of control” flies,  invasive mussels, and now at-risk oysters.

Today he teaches and carries out research at the State University of New York at Albany,  Molloy says growing up in the Bronx, his parents nurtured a passion for science.

“My family was lucky to stay on Lake Hopatcong in New Jersey; and I spent most of my time in that water, with my little snorkel and my little fins, and I just got a tremendous appreciation for the wonders of what’s going on biologically in lakes,” Molloy says.

Credit D. Molloy
Molloy (left) during streambed sampling with colleagues Barbara Griffin and Bob Struble - in 1985

Molloy's  first research opportunity emerged when he began his doctoral studies. The New York State Museum approached him with a scientific challenge: could he come up with a control for black flies plaguing tourists in the Adirondacks,  without harming other living things in the process

“Tourism is one of the major industries in the Adirondacks, so it’s a pretty important thing to try to control them. And back in the 50s and 60s planes were just flying, spraying out stuff to kill the adult black fly. The question was could you use biological control to control black flies that are biting people. No one thought there would be a solution,” the scientist says.

Molloy's quest drew wider attention; black flies were a bigger problem than the nuisance they presented in a U.S. tourist destination, but in other parts of the world, the flies were spreading parasites to humans.

“We received our funding primarily from the World Health Organization which is part of the United Nations and the reason for that is, not in North America, but in the tropics, black flies spread the disease of blindness; it’s a parasite it carries,” Molloy says.

Molloy, working in conjunction with an international team of scientists, hit on the black fly control solution.

“It was by putting a bacterium, not one, but literally millions into streams and rivers where the black flies breed. It’s one of these spectacular successes of biological control. It goes by the acronym BTI,” Molloy says.

Molloy moved on to fight  invasive creatures -  quagga and zebra mussels.  They entered the Great Lakes, likely in the 1980s, through ballast water from ocean-going ships.  The mussels made themselves very much at home.

“They call zebra mussels and quagga mussels 'ecosystem engineers' because when they come in they change the dynamics of the ecology of the water bodies they’re in,” Molloy says.

The invasives impacted power plants in New York State. That’s how Molloy got involved in the project, and where his funding came from.

“In 1990 someone from the Department of Environmental Conservation came to me and said, you’ve worked on black flies, did you ever think of working to try to control zebra and quagga mussels because they’ve come into our power plants in New York State and those plants have no defense but putting some pretty broad spectrum chemicals that are designed to clean out anything in the pipes. Have you ever thought of coming up with a biocontrol agent that could be used by the power industry,” Molloy says.

The power industry picked up the tab for  Molloy’s research that began in 1991.

“We went out into the environment and collected bacteria; we isolated bacteria. It didn’t matter where we were isolating them from, but we kind of did a lot of work in mud in rivers. We also contacted colleagues who have “libraries” of bacterial cultures. So the vast majority of things we tested were from colleagues of mine who would send 40 or 50 different types of bacteria,” the scientist says.

Molloy and his lab team spent four intensive years on the project and says he was about to give up.

“We tested over 650 strains that did not kill zebra mussels,” Molloy says.

Two months after he was ready to call it quits, Molloy’s team found the "fix" in the muck of a river ‘somewhere in North America.’

“The river didn’t have zebra mussels living in it. This has nothing to do with zebra mussels. It’s just serendipity that when they eat it, they die,” Molloy says.

Molloy has since left the Museum, where scientist continue  mussel research.

“I retired and came here to the University at Albany and I handed off that grant to Dr. Denise Mayer at the New York State Museum. I basically passed the baton to Denise and our U.S.G.S. colleagues,” Molloy says.

He has not retired from research.  Now at the State University of New York  at Albany, Molloy is picking up on a project in which he’s long been interested. It has to do with oysters, and their diminished populations in the Chesapeake Bay and along the Atlantic Coast.

“I’ve known about the dramatic decline that occurred in the 1950s.  Ninety five percent of the oysters were decimated in their prime breeding areas where people were harvesting them; tremendous loss and they’ve never recovered,” Molloy says.

The killer is known – spore-forming parasites called haplosporidians. But Molloy says scientists have been unable to figure out exactly how the oysters become infected.

He's now heading up a team of North American and European scientists that recently described a new haplosporidian species - a freshwater version of these parasites infecting, of all creatures, zebra mussels.

“We’ve located it in several water bodies  in Western Europe where it’s killing zebra mussels. So what I want to do is work out the life cycle of this haplosporidian species that infects zebra mussels; I especially want to discover how zebra mussels become infected.  There's a real good chance that there's another aquatic critter - another host in the water - that the parasite must pass through before coming back and infecting more zebra mussels.  Once I find out what that critter is, then I want to  share that information with the people who work in the marine habitat, like Chesapeake Bay, and they can look for a similar saltwater critter and see if it is serving as the alternate obligate host in the life cycle of the species that kills the Eastern oyster,” Molloy says.


Molloy shot this video during collection of haplosporidian-infected zebra mussels in a lock on the Meuse River in France.  Working with him were University of Lorraine  scientists Philippe Wagner and Laure Giamberini.

Credit L. Giamberini
Molloy dissecting haplosporidian-infected zebra mussels in France.

With preliminary work now completed, Molloy is currently assembling a team of international scientists who will join him to launch this haplosporidian life cycle project; just  the latest,  seemingly unsolvable,  challenge in Molloy's career.

Click to find a recent New York Times article about his work.

Susan is WUWM's environmental reporter.<br/>