KINTNERSVILLE, Pa. — Aphids are an honored guest at Peace Tree Farm — a wholesale greenhouse specializing in herbs, veggies and specialty plants.

The aphids are brought in and encouraged to breed.

While that may seem counterintuitive, it’s all part of a system of biological controls at Peace Tree. Instead of spraying chemical pesticides on the plants that fill their 55,000-square-foot greenhouse, Lloyd and Candy Traven rely on an array of beneficial predatory insects and mites, as well as nematodes and bacteria, to maintain a pest-free environment at their organic growing operation.

The business was started in 1983 when the husband and wife bought a small commercial greenhouse near Nockamixon State Park in Bucks County. Candy suggested they grow herbs.

“I thought it was the single stupidest idea I had ever heard in my life,” Lloyd said. “Who the hell is going to buy basil? Basil? What do you do with it, right? And you know, who’s gonna buy dill, parsley, rosemary?

“And so we sold 5,000 (herbs) the first year, about 20 times what I thought we would sell. I’m a bright guy. I figured that out real quick that, well maybe, there is something here.”

Today, a good third of their business is selling herbs wholesale to garden centers and big retailers like Wegmans.

The Travens describe the nature of their relationship in the business as “the head and the heart.”

Lloyd — the head — has the deep knowledge of growing plants.

A graduate of Delaware Valley and Cornell universities, studying horticulture and ag economics, he was recruited out of grad school by Ball Seed Co. to work as assistant to the president for special projects.

“He recruited me personally,” Traven recalled, “and my job description for him was really interesting. He said ‘Your job is to make me feel stupid.’ I said, ‘I’m your guy.’”

He worked on many projects for Ball that revolutionized the industry, concepts like unitized plug seedlings and pelletized seeds, things that made commercial greenhouses more efficient and more profitable for the growers.

Candy, on the other hand, is the heart of the operation.

“I take care of everything that needs to be taken care of that I am capable of,” she said. “I take care of the money, I take care of the people, making sure everybody is happy. I take care of details. Pretty much the only thing I don’t do is drive a truck.

“I instinctively know what we need from having done it forever.”

While not quite forever, Peace Tree has been around for a long time. So long, in fact, that the Travens’ son, Alex, has had enough time to grow up, go to college, move away from home, and return to Peace Tree with his own unique but relevant set of experiences that he now applies to the business.


Alex is in charge of the entire biological control program. He manages the menagerie of predatory and parasitic species, keeping their populations strong and robust.

That’s where the aphids come in.

Hanging from one of the middle gutters in the greenhouse are aphid banker plants, baskets full of pasture grasses that provide habitat for a specific type of aphid called the bird cherry-oat aphid.

The baskets are hung where predatory insects and parasitic wasps will find them and lay their eggs on the animals. In turn, a new generation of predators hatch and continue the biological pest control cycle in the greenhouse.

Peace Tree has many different types of banker plants to provide habitat for various types of bio-control species.

Pots of common mullein, for example, grow all around the greenhouse. It is home to many species of predatory insects such as Dicyphus, which lives and breeds on the leaves.


Baskets of ornamental pepper plants called Jack Flash hang throughout the growing space. These give shelter to what Lloyd Traven calls his “thrip killers,” otherwise known as Orius insidiosus or the minute pirate bug.

“Before I started out here,” he said, “I had never heard the word thrips — never heard the word, OK? So here I am, I worked my way through college as a grower, went to graduate school, worked for a commercial company, and I’d never heard of thrips before.”

And why is that?

“Because we had Temik. So with Temik on the shelf you don’t know about any insects. I mean there’s nothing. There’s no whitefly, there’s no aphids. And so I was trained as a classic grower. And that mentality is, if it moves, you kill it.”

But eventually, Traven came to see things differently. His aha moment came one day when he was unloading flats of herbs to a garden center and a customer started eating the herbs.

“And I’m thinking, ‘Oh my god, don’t eat that. I know exactly what’s on it,’” he said. “So we started to look for what I call the softer chemistries: insect growth regulators, nonpersistant pyrethroids, instead of organophosphates and stuff like that.”

But eventually even the pyrethroids became too much for him, so he transitioned to organic growing and eventually got into biocontrol.

“So I started on biocontrols probably 2003, 2004 maybe,” he said. “And there was nobody doing it then. I mean there might have been a few vegetable growers doing it. But people look at it like, ‘Are you crazy?’”

Alex, on the other hand, is sort of an organic native.

“I didn’t grow up with having conventional spray regimens be the norm for me,” he said. “So for a lot of growers, it’s that they have to make some kind of mental and emotional leap from the conventional to the biocontrols, and it’s a very different mindset.”

Biocontrol is “very proactive,” he said. “You don’t get the superhero moment where you see the problem, you come in and you spray, you see all the bugs dead and everybody claps and you save the day. With biocontrols, if it’s ever to the point where you’re seeing a problem, it’s almost too late to do anything at that point.”

Ronald Valentin, technical lead and commercial manager for North America at Bioline AgroSciences, a leading force in the biocontrol industry, has been working with Peace Tree Farm for over a decade.

“The main driver for biological control always has been pesticide resistance,” he said. “Back in the ’60s and ’70s, really it was not the concern about environment, it was strictly because pesticides were failing. Insects were building up resistance to pesticides and growers were having a hard time just controlling pests.”

But consumers are starting to demand their food be grown in a safer, less impactful way.

“Peace Tree has been on the forefront of this,” Valentin said. “Lloyd has really embraced it with both hands, and I think that’s a really important point. If you start using biological control, you can’t jump in halfway. You do it or you don’t do it. It’s a commitment, and you can see that throughout the entire operation at Peace Tree.”

So is biocontrol cheaper to operate than a chemical spray program?

“No,” said Lloyd. “But it’s not more expensive than chemicals either. And it works better. In addition to that, we have less labor than we would if we were spraying — with less exposure.”

Peace Tree Farm

Aphid Banker Plants

Mullein in the Greenhouse