Cultural Pest Management

1 September 2004

Virginia Cooperative Extension, Charlottesville/Albemarle County Office
460 Stagecoach Road, Charlottesville, Virginia 22902
phone: 434.872.4580   fax: 434.872.4578

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Managing pests in the landscape can be done in many ways. Often there is no one way that is effective alone. By integrating multiple methods of pest management we are often able to reach a satisfactory situation. The goal is to reduce pest populations to a low enough number so the threat of damage is minimal. Eradication of a pest is rarely practical when it comes to our common, well-established problems. In these cases it is actually a good idea to leave a few of the bad guys out there to provide food for their natural enemies.

One of the keystones to managing pests of all kinds is called cultural pest management. The idea here is to manipulate the environment to reduce the likelihood of pest problems. By making an area less attractive or unsuitable for a pest, there is a very good chance the pests will be less likely to survive in that environment or they will find somewhere else to go. Because these sorts of tactics are proactive instead of reactive we can also call this preventive pest management.

Cultural pest management methods include a broad range of practices that can be modified or manipulated to manage one or more pest problems. Cultural techniques may include crop rotation, tillage, timing of planting and harvesting, cover crops, choice of plant cultivar, competition, fertilizer or irrigation practices, and sanitation. Cultural methods are more effective when used in conjunction with other pest management strategies (e.g. mechanical, biological, and chemical control methods).

Weed control approaches often include hoeing (mechanical) and herbicides (chemical). However, cultural weed control methods could also 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.

Plant diseases are often difficult to control once they appear. Cultural practices can be used effectively to prevent some plant diseases from getting started. Disease resistant plant varieties and rootstocks are available in many cases. In vegetable and fruit gardens and annual flower beds, crop rotation and sanitation are easy and effective. This means you should not plant the same species or same family of plants in the same bed in successive years and you should remove diseased plants as soon as symptoms appear. Never compost diseased plant material and remember to clean up your garden at the end of the season so diseases and insects do not overwinter in the refuse.

Many insects can also be controlled using cultural methods. For instance, some insect populations lay their eggs in the soil near where they were feeding this year so their offspring will be able to find food easily next year. If you moved your beds or rotated your crops those young insects will go hungry and their population will be reduced. Aphids can be reduced by not applying excessive amounts of nitrogen fertilizer which can create very succulent foliage that attracts aphids. Spider mites, thrips, and other pest populations can be reduced by knocking them off plants with a spray of water from your hose so they can be gobbled up by predators such as ground beetles. Reducing nearby weeds where many insects find shelter and alternative food sources during the growing season and over the winter will help as well. Other options include tillage to expose soil insects to predators and the elements and trapping.

There are traps available that can reduce populations somewhat but mostly traps provide good information on what insects are present during which part of the growing season so you know when to take action. One of these devices is called a sticky trap and consists of a plastic card colored to attract certain insects and covered with a sticky substance to catch the insects.

Knowing your ecosystem, that is the plants in your landscape and the potential problems and good bugs you might find, will help you make quick and educated decisions when a problem does occur. It is a lot of information to keep up with but if you take in a little bit at a time while you are out in your landscape each week it is not so overwhelming.

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For more information about landscape topics contact your local Virginia Cooperative Extension office. Many county Extension offices have a help desk that is staffed by Master Gardener volunteers. These volunteers are trained to answer questions about home and landscape pest problems. The local Virginia Cooperative Extension office numbers are Albemarle 984-0727, Fluvanna 591-1950, Greene 985-5236, Louisa 540-967-3422, and Nelson 263-4035.