Talking Shop: Using Lighting To Boost Beneficials
Peace Tree Farm in Kintnersville, Penn., is an organic growing operation, and as such, it is completely focused on using biocontrols rather than chemicals in its greenhouses. This means a strong reliance on beneficial insects, as well as banker plant systems that will give them a home.
One of the beneficials the company uses the most is the insidious flower bug (Orius insidiosus), a species of minute pirate bug.
“It’s like the diesel engine of thrips control for us, and we are dedicated to using it in our greenhouses,” says Lloyd Traven, owner of Peace Tree Farm.
However, one of the main problems with Orius is that it goes through a significant period of diapause during the winter and, in natural conditions, will shut down for long periods of time. As a result, Peace Tree has had to rely on very early development of banker plant systems. These plants, such as purple flash pepper, must have enough time to grow to a significant size and provide an attractive home for the Orius.
“It takes 26 weeks from sow to an active banker plant, and they have to be big enough and blooming to support a beneficial operation,” Traven says.
The time involved in this approach means the Orius may emerge too late for effective thrips control.
“So we asked ourselves, is there a way we can keep Orius alive throughout the winter?” Traven says.
The first answer was to simulate longer days with the use of HID lighting. The problem, however, was that Orius was attracted to the light, to the point that it would fly up and literally get cooked.
“A week after you turn on your lights, all the Orius were dead,” Traven says.
Give Orius Enough Light, But Not Too Much
Fortunately, the next option Peace Tree Farm chose has been more successful.
“We bought an HID lighting system with a rotating reflector in it,” Traven says. “It produces beams of light and a motor rotates the reflector around the bulb, forcing the beam laterally and changing the intensity over the plant constantly.”
As it rotates, it sweeps across the benches until it’s pointing 180 degrees laterally in the other direction.
“We can put one light in a 42-foot-wide greenhouse and light two benches on either side of an aisle,” Traven says.
The fact that it rotates means there are periods of darkness, then increasing light.
“What we found is that the Orius got just enough light that it didn’t feel like it was winter, and not too much light that it would be instantly attracted,” Traven says. “So it kept on breeding.”
The big buildup of Orius is in January and February, and they are distributed in mid-March. The key is that there is a thriving population before the big spring warmup and thrips explosion.
Since then, Traven says the thrips only turn up where you expect to find them, and in a manageable number.
Traven says Peace Tree will continue to release Orius directly on “hot spots” — thyme and rosemary are always a place where they will congregate, as well as sages — because those plants are difficult for other predators to populate.
“All the volatiles, the pubescence and the oils, serve to confuse or repel or deter the other beneficials, predatory mites, in particular,” Traven says
“This was an application of lighting technology that, in a precise, innovative way, worked terrifically for us,” Traven says. We knew we needed to look at the technology in a completely different way, and it worked out well.”
It’s also been a cost saver given the sometimes hefty price tag of using Orius.
“They are expensive to grow and maintain, so you really don’t want to release them only to have them die,” Traven says.
Color May Matter
Lloyd Traven of Peace Tree Farm has another theory when it comes to lighting, and it’s that color matters.
He already knows how plants react to red and blue lighting versus green, but what about insects?
“I think it’s time to experiment with green LED lighting to see if beneficial insects like Orius might detect it and feel like they are under long daylight conditions,” he says. “There’s no reason why it shouldn’t be able to sense the green light.”
Traven says he knows that researchers in Holland are looking into this concept already, and he’s hoping some scientists in the U.S. will follow suit. During the Biocontrols 2015 Conference & Tradeshow in California in early March, he discussed the topic with research peers, and ultimately hopes a plant physiologist will investigate it.
“It could be a life-altering option for those of us who use biocontrols,” Traven says. “If we can keep Orius popping through the winter, we can solve a lot of problems.”