Ecology vs. Convenience
June 27, 2011
I hardly ever get asked about our growing practices at the farmer’s market. I’ve never been asked how, without pesticides, we control insects and disease. Organic growers are allowed to use a variety of relatively safe pesticides on their crops, including Bt (the bacteria whose genes were incorporated into GE corn), Surround and Entrust, the chemicals we use at Drumlin. With an interest in agroecology and a deep-seeded anxiety about sprays I was excited to attend the CRAFT about organic insect management held at Waltham Fields Community Farm last week.
Influenced by Michael Pollan, The Farm as Natural Habitat, and The Vegetable Gardener’s Bible, my beliefs about managing pests are mostly idealistic and not backed by practical, especially commerial farm scale, experience. That being said, what I’ve come to understand is that pesticides in general are a way to control nature, rather than working your farm into its folds. I find the agroecological techniques of controlling pests through biodiversity much more attractive than spraying for potato beetles, though I admit sometimes it must be necessary. There are a diversity of ways to control pests to reduce the need to spray. I was excited to learn about them from Ruth Hazzard, an entomologist at UMass Extension who ran the CRAFT.
In the pouring rain I could barely hear the buzz words that I needed explained: Integrated Pest Management, organic pesticide, among others. The whole group seemed to feel comfortable with the terms, but when the Drumlin apprentices debriefed on the way home we thought they probably weren’t. We couldn’t imagine that other folks didn’t also want a groundwork laid before jumping into the complicated tasks of calibrating back pack sprayers and calculating what fraction of an acre needed what concentration of a chemical. With the focus on pesticide application the talk breezed over ethical concerns, whole farm ecosystem approaches to pest management, and prevention.
As I watched the sprayer tractor implement drive slowly down the flower field as a demonstration I had the unsettling feeling that we’d missed the boat. I was excited, but also a bit disappointed to have to find the missing pieces in my home library. Excited at the ecological ideas forming in my head about pest management on the farm, but disappointed that a network of farmers, together in a CSA distribution hut, didn’t even discuss them.
Right off the bat Edward Smith, author of The Vegetable Gardener’s Bible declares that pest management is really about ecological robustness. The question should be: What ecological problem is causing this pest problem? Not, how can I spray Surround through a backpack sprayer? Smith offers a number of techniques to increase biodiversity in a way that decreases susceptibility to pests. Admittedly, he writes about personal consumption growing, where intercropping won’t decrease efficiency drastically and where attention to detail is a much smaller job than on a 12 acre farm. Nevertheless, I thought the CRAFT we have been a great opportunity to talk about how larger scale growers are adapting garden-scale companion planting, which could significantly reduce pests. I’d also like to hear how farmers encourage disease-fighting soil microbes and if they use nematode sprays.
I learned some exciting things in The Vegetable Gardener’s Bible. Onions and other plants in that family can deter pests by masking the smell of their preferred crops. Many flowers and herbs drive off specific pests in the same way. Beans and potatoes together can stand up better to Mexican bean beetle and Colorado potato beetle than when they are planted farther away. Keep plants in the same family separate from one another to avoid host plant buffets. Trick the pests with time: if you plant crops a little later than usual, their pests will emerge before their food source is in the ground and they’ll be forced to move on.
When I read “Like many predators in nature, garden pests tend to attack the easiest prey. They’ll even bypass the healthy, vigorous plants to attack the stressed ones (158)” I started getting ideas. How can these tips come together? I thought up a sort of sacrifice zone, an area at the end of the bed with plants that are purposefully weaker than the rest. These plants would not be fertilized or weeded. They could even be a different plant than the crop, perhaps one in the same family that the pests prefer. Also in this no-harvest zone could be a mixed seed of an Allium and flowers/herbs to mask the crop’s smell. This zone could have productive as well as protective power, since flowers and herbs have economic value.
Agroecological techniques to pest management have an ecological return on investment. The loaded question I should have asked Hazzard is: How can we be sure pesticides are truly worth it? The short-term suppression of pests through sprays, organic or not, is a reflection of the lasting paradigm of farming as the human control over nature. But when the beetles and fleas and mites, maggots, miners, and borers march into the fields any farmer will tell you, we live in the hands of the gods.