3/29 Whoa! Bugs in the Greenhouse!

Some of you may have read about our farming practices, and noted that we have been trying to regulate our pest problems in both our vegetable and ornamental greenhouses with biologic pesticides and the introduction of parasitic and predator insects.  Our motivation for this type of insect control are a couple of reasons. It is environmentally safer and cleaner for growers and end users. The downsides are many, not the least of which is that it is a very expensive form of control. It is more complicated than just reading the label and spraying a pesticide for a pest. The product (good or “beneficial” bugs) do not have a shelf life as the bottle of pesticide does.  And when a problem arises, it can take six to thirteen days for the product to arrive after ordering it. You have to know the life cycle of the bad bugs as well as the beneficial insects. That makes things yet more complicated. (I wanted to be a farmer, not an entomologist…)

So it’s a big deal, it’s expensive and complicated. It is an art as much as a science. But we have been trying to do it this way for fifteen years. We have now developed an annual plan of prophylactic releases,  based upon when we open greenhouses, what plants go in them, the crops, and the historical problems that have cropped up and when that has occurred.   All this, knowing that at some point in the spring aphids, white flies and thrips  (the horticultural equivalent of President Bush”s “Axis of Evil”)  will show up. Hand in hand with the prophylactic release of beneficial insects there comes  a monitoring or “scouting” plan that weekly makes you systematically assess insect and disease problems by observing trends in insect populations. For example, you are never going to be totally”pest free” so by observing and counting pests weekly on a yellow sticky card that attracts the pests and understanding the swell and ebb of populations, you can make a pest control strategy. Sometime things run like a top, sometimes they go to hell in a hand bag. You can always tell when the latter happens because you can read the lines of frustration in Anne and Pooh’s faces. But when its working right,there are enough predators to keep the  populations of bad guys surpressed  but enough bad guys to support a healthy population of predators and beneficials. Its a balancing act. See? I told you it was tricky.

We didn’t come up with this kind of control on our own. We weren’t that smart. Some forward-thinking individuals from the Extension Services of our land-grant universities in Maine, Vermont and New Hampshire got together about 15 years ago and said “There has got to be a better way than hammering away at an insect pest problem with chemicals until the bug develops resistance and we have to find another chemical…besides I hear that Pooh Sprague hates spraying his greenhouses weekly…”  Well, maybe not the last part, but they were savvy enough to realize there might be a way of mimicking the way the natural insect populations are kept in check in an outdoor environment, and adapting that to a greenhouse environment.

So when you come to the greenhouses this year you will see little yellow cards again and you will know that we are monitoring pest populations with them. UVM is doing some experiments here, and you will be told that certain plants can’t be sold. And you will know that the tiny parasitic wasps we released at dusk on Tuesday are going about their business as you go about yours. And you can, we hope, appreciate the fact that we are trying to reduce our biologic footprint in our own corner of the world. 

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