Using Cultural Pest Control Methods - August 4, 2004
Jeff Schalau, County Director, Agent, Agriculture & Natural Resources
Arizona Cooperative Extension, Yavapai County
Cultural control methods include a broad range of normal management practices that can be modified or manipulated to manage one or more pest problems. Cultural control techniques may include crop rotation, tillage, timing of planting and harvesting, cover crops, choice of plant cultivar, competition, fertilizer or irrigation practices, sanitation, and soil solarization. Cultural controls are often most effective when used in conjunction with other pest management strategies (i.e. mechanical, biological, and chemical control methods) and should be part of every gardenerís integrated pest management (IPM) strategy.
Weed control approaches often include hoeing (mechanical) and herbicides (chemical). However, cultural weed control methods could include tillage, mulching, reducing inputs of irrigation and fertilizer, reducing weed seed sources, and using more desirable plants that compete with weeds. Reducing weed seed sources can be done by hoeing or pulling annual weeds before they go to seed and limiting the introduction of outside sources which may include maintaining borders, not importing weed-contaminated soil, and only using well-composted manures. Weeds tend to grow where bare soil and water are available. In these circumstances, you can use mulch or consider planting wildflowers and/or native grasses to reduce the area available to weeds.
Disease resistant plant varieties and rootstocks are available in many cases. However, plant diseases are often difficult to control once they appear. Cultural practices can be used effectively to control some plant diseases. In vegetable gardens and annual flower beds, crop rotation and sanitation are easy and effective: donít plant the same species (or plant family) in successive years and remove diseased plants as soon as symptoms appear. Never compost diseased plant material. Soil solarization requires a greater input of time, energy, and materials, but can be effective in controlling weeds as well as soil-borne diseases. For more information on soil solarization, see the May 21, 2003 Backyard Gardener on the web site or visit one of our offices.
Many insects can also be controlled using cultural methods. For instance, aphid populations can be reduced by controlling weeds where they take refuge, controlling ants (they protect aphids to harvest the honeydew), and by not applying excessive amounts of nitrogen fertilizer which can create very succulent foliage. Spider mite populations can be reduced by taking steps to reduce dust and washing plant foliage during the growing season. Thrips can be also be knocked off plants with a spray of water and reducing weeds where they may find refuge. Whitefly populations can be reduced early in the growing season by using reflective mulches such as aluminum foil or plastic sprayed with silver paint. These should be removed before summer temperatures peak to avoid damaging the crop. Traps are also available for many insects.
Birds are protected by law and it is illegal to harass, trap, or kill them without first consulting the Arizona Game and Fish Department. The only exceptions are starlings, English sparrows, and pigeons (rock doves). Exclusion (bird netting, caging, etc.) is the best solution to prevent bird damage. Frightening (owl decoys, Mylar streamers, etc.) will sometimes repel birds for a few days, but they often habituate to these devices over time.
Cultural controls are not very effective in controlling animal pest populations. Exclusion (fencing/blockage) is probably the best control method for deer, rabbits, skunks, raccoons, and javelinas. Gophers, packrats, and rock squirrels are best controlled through trapping and removing the attractant(s). All animal species except gophers, packrats, and rock squirrels are also protected and may not be harassed, trapped, or killed without consulting Arizona Game and Fish Department. Electronic frightening devices have not been proven to be effective by any research for any species of animal or insect.
The University of Arizona Cooperative Extension has publications and information on gardening and pest management. 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 firstname.lastname@example.org 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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