Farmscaping - April 23, 2008
Jeff Schalau, Associate Agent, Agriculture & Natural Resources, Arizona Cooperative Extension, Yavapai County
Insect pests pose serious challenges to many gardeners and orchardists. While pesticides can be used to control these insects, pesticides can also kill beneficial insects (pollinators, predators and parasites). Increasingly, gardeners are looking for non-chemical pest control alternatives. Last summer, I learned about farmscaping while touring an organic orchard in central Michigan. I thought readers might find it interesting.
Farmscaping is a whole-farm, ecological approach to pest management. It uses non-crop plants to support populations of beneficial insects. To accomplish this, farmscapers use hedgerows, insectary plants (plants that attract and feed beneficial insects), and cover crops to provide habitat elements (food, water, shelter, and space).
Biocontrol uses natural predators and parasites to control pests. Insect biocontrol has been used in greenhouses for a long time. In these closed systems, predators and parasites are introduced and held captive to feed on pests. If they are highly successful, they will run out of food and pest populations will dwindle. When pests return, often they must reintroduce biocontrol insects which are purchased from companies that raise them specifically for that purpose.
Farmscapers enlist native populations of beneficial insects to assist them by creating prime habitat for them right in the fields. Farmscapers view beneficial insects as mini-livestock. The beneficial insects will be healthier, reproduce more readily, and be more effective biocontrols when provided habitat with an adequate and easily available diet of nectar, pollen, and herbivorous insects and mites as food to sustain and increase their populations. Flowering plants are particularly important to adults of the wasp and fly families, which require nectar and pollen sources in order to reproduce the immature larval stages that parasitize or prey on insect pests.
Farmscaping requires thought and planning. Simply selecting a random group of plants could result in a situation that favors pest species. This is why it is important to identify those plants, planting situations, and management practices that best support populations of beneficial insects. Farmscaping requires greater knowledge and management skill than conventional pest management. The farmscaper’s payoffs are reduced pesticide use and associated costs, reduced pesticide residues on crops, and an overall safer farm environment with increased biodiversity.
Guidelines usually suggest planting 1-5% of the total field area to “farmscaping plants” in rows between crop plants. Data suggests that planting permanent insectary rows is superior to planting then annually. Depending on the plant species, these “perennial islands” provide food resources for beneficial insects as well as overwintering sites. During the year, beneficial insects can colonize the crop plants directly from the adjacent farmscape.
Many gardening catalogs sell seed mixes for farmscaping applications (often called “beneficial blends” or “insectary blends”). These mixes will usually contain plants in the carrot, sunflower, and mint families. Seed mixes may or may not contain cover crops (legumes and other soil building species). Cover crops that are good insectary plants include buckwheat, sweet clover, fava beans, vetch, clover, mustards, and cowpeas.
You might try some of the following plants in a farmscape plant/seed mix for the Verde Valley: sweet clover, alfalfa, gypsophila, alyssum, yarrow, black-eyed susan, evening primrose, cowpeas, basil, carrot, dill, parsley, and fennel. London rocket, a naturalized mustard will no doubt be in the area already. If you decide to try farmscaping, plan carefully, record what you planted and when, observe the results, and share your findings with others. Natives and landscape plants can also contribute to the farmscaping potential of your garden or orchard. For this reason, I would also suggest recording the species and bloom period of other plants in the vicinity of your garden and orchard.
For more information, consult the National Sustainable Agriculture Information Service Publication Farmscaping to Enhance Biocontrol on the web at extension.oregonstate.edu/sorec/sites/default/files/farmscaping.pdf. This 40 page publication is an excellent resource for farmscape planning, seed venders, research projects, and applications.
The University of Arizona Cooperative Extension has publications and information on gardening and pest control. If you have other gardening questions, call the Master Gardener line in the Cottonwood office at 646-9113 ext. 14 or E-mail us at email@example.com and be sure to include your address and phone number. Find past Backyard Gardener columns or submit column ideas at the Backyard Gardener web site: http://cals.arizona.edu/yavapai/anr/hort/byg/.
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