But there is some good news. The price of wasps has come down from around $40 a vial to a little less than half that and the Boyds no longer have to use some of the pesticides that they once did to control the aphids.
Like many greenhouse growers in Vermont, New Hampshire and Maine, the Boyds control aphids and other pests by releasing predatory and parasitic insects to attack the bugs that threaten the plants. The wasps cannot sting people but they do puncture the aphid’s body with an ovipositor. The ovipositor deposits an egg into the aphid. The egg hatches and the wasp larva hungrily feeds on the internal organs of the aphid, killing it as thoroughly as any pesticide.
According to D J Boyd, it is not less expensive than using the pesticides that he used to put into each pot of soil, but he is glad to be done with the synthetic pesticide that he was using. “We aren’t using the systemics or the aerosols anymore in the greenhouses. We are not organically certified yet, but I am hoping that we will grow into that,” said Boyd. “Right now we use sticky traps in the greenhouse to tell us if there are any little hot spots where there are aphids in the greenhouse, and we will still use some insecticides like pyrethrins or even some soap to control the aphids in those spots. But we use way less than we used to since we started using the wasps.”
For a while, Boyd tried to rear his own wasps in special insect cages. The tightly sealed cages were filled with plants that had aphids on them. The aphids were exposed to the wasps, and the wasps that hatched were
eventually allowed out of the cage into the greenhouse, where they were needed. According to Dr. Margaret Skinner at the University of Vermont’s Entomology Research Library, using these “banker plant systems” can be a very effective and economical way to control aphids.
In the end Boyd simply found it easier to buy them. “It was one more ball in the air. Trying to make sure that the aphids I was raising in the box were still alive, or that the plants in the box had been watered, was just one more thing to do. And the other balls in the air, the other things that I needed to do on a given day, if I let one of those go, that could end up costing us money, too. When I heard that the price for vials of wasps has come down so low compared to how expensive they were just four years ago, it’s just easier for me to buy them and release them directly into the greenhouse than grow the wasps myself,” said Boyd.
It may not be easier to cut all their wood instead of using propane to heat the greenhouses, but Boyd reports that they are saving a ton of money since they switched to their new wood furnace and boiler. “Look at the size of this thing.” said Boyd, as he opened the door of the furnace. “It just eats up wood. We have to cut the wood and bring it down here to the farm, but it really is worth the time.”
The furnace heats water that is then piped to a fan in the greenhouse. The water releases heat into the air in the greenhouse, and the water is then recirculated back to the furnace. They only use propane as a backup.
According to Vern Grubinger at the University of Vermont Extension, the service has been promoting these types of heating systems because they don’t use fossil fuels, use a locally available fuel source, and can save farmers money when compared to a furnace that uses propane or oil.
“Some growers in Vermont are using corn furnaces. There is a lot of energy in a kernel of corn,” Grubinger said.
One of the things Boyd likes about their furnace is that besides burning cord wood, it can also burn brush. “We are cutting the brush anyway, and all of that becomes fuel, too,” Boyd said.