   Cultural and Mechanical Pest Management - October 9, 2013 Jeff Schalau, Agent, Agriculture & Natural Resources University of 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 gardener’s 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 encouraging 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 growing space 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: don’t 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 some soil-borne diseases. For more information on soil solarization, see the May 21, 2003 Backyard Gardener on the web site. Many insect populations may be reduced using cultural methods. For instance, aphid populations can be reduced by managing weeds where they take refuge, controlling ants (they protect aphids to harvest their 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 also be knocked off plants with a spray of water and reducing weeds where they may find refuge. Sticky traps are also available for many insect pests. In San Diego County, I have seen both yellow and blue sticky tape barriers surrounding hillside tomato plantings. These tapes attract the insect and they become stuck on the sticky surface. The yellow attracts aphids, leafhoppers, flea beetles, and cucumber beetles while the blue attracts thrips and leafminers. Most birds are protected by the International Migratory Bird Treaty Act and it is illegal to harass, trap, or kill them without first consulting the U.S. Fish and Wildlife Service. The only exceptions are starlings, English sparrows, and pigeons (rock doves). Exclusion (bird netting, caging, etc.) is the best solution to prevent bird conflicts and/or damage. Frightening (owl decoys, Mylar streamers, etc.) will sometimes repel birds for a few days, but they often habituate to these devices over time. Many nuisance birds live in flocks (starlings, pigeons, swallows, ravens, etc.): an interdependent social order where each bird acts as the eyes and ears of the group. When one senses danger or a food source, the information is immediately relayed to the rest of the flock. Electronic devices have been developed to repel birds. These devices use bird alarm and distress calls and predatory bird calls to cause the flock to flee. These devices are becoming increasingly popular with pecan orchards and vineyards. Cultural controls are not very effective in controlling mammalian pests. 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, altering habitat, 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. Some electronic frightening devices have been developed for deer with successful results. However, electronic devices are not effective at repelling rodents or insects. Follow the Backyard Gardener on Twitter – use the link on the BYG website. If you have other gardening questions, call the Master Gardener help line in the Camp Verde office at 928-554-8999 Ext. 3 or e-mail us at cottonwoodmg@yahoo.com and be sure to include your name, address and phone number. Find past Backyard Gardener columns or provide feedback at the Backyard Gardener web site: http://cals.arizona.edu/yavapai/anr/hort/byg/.  |