By Brett McGhie, Butte County Master Gardener, February 1, 2013

Integrated Pest Management (IPM) is a science-based pest management process which focuses on the long-term prevention of pests and their damage by managing the ecosystem.  The University of California Division of Agriculture and Natural Resources has developed an IPM program dedicated to helping Californians “prevent and solve pest problems with the least unintended impacts on people and their environment.”  For the home gardener, a guiding principle of IPM is to understand why your landscape favors particular pests, and help you enact changes which will make that environment less attractive to those pests.

The first steps in the IPM process involve identifying what pests are present and then monitoring their numbers and the extent of the damage they are causing.  At this point, it can be determined whether the pest can be tolerated, or if further actions need to be taken.  The guiding principal with IPM is to use the least harmful control method(s) that will be effective in managing a particular pest.  These methods include one or more of the following: cultural controls, biological controls, mechanical and physical controls, and chemical controls.

Cultural control involves creating an environment that prevents and/or reduces pest populations.  Practices such as careful site selection, sanitation (removing garden debris), water management and fertilization are examples of cultural control.  Many pests overwinter in garden debris left lying on the ground.  If plants are stressed because of poor growing conditions, they are more susceptible to insect attack.  Fungal diseases can be encouraged if too much water or fertilizer is applied to the garden.  Controlling pest damage might also be as simple as selecting plants that are disease- or pest- resistant. In the long run, good cultural practices often eliminate the need for other pest control measures.

Biological control uses natural enemies, such as predators like ladybeetles, lacewings, or praying mantis, to control pests.  Natural enemies also include parasites and pathogens (diseases that attack the pest).  For example, several tiny wasp species parasitize garden caterpillars, and the pathogen Bacillus thuringiensis, is a commercially-available bacterium that attacks caterpillars, but is nontoxic to other organisms.

Mechanical and physical controls either kill a pest directly or exclude it from an area.  A gopher trap is an example of mechanical control.  Physical control includes mulching, cultivation, or mowing to eliminate weeds, and the use of nets and screens to exclude insects and birds.

Chemical control is the use of pesticides.  With IPM, pesticides are used as a last resort and in combination with the other control methods mentioned above.  If pesticides are deemed necessary, it is important to use them as selectively as possible and to take into consideration how safe a pesticide is for other organisms, including the natural enemies of the targeted pest.

The Butte County Master Gardeners, along with Master Gardeners statewide, have been trained in the UC Agriculture and Natural Resources IPM program and are ready to support local gardeners who are interested in utilizing this approach to pest management. If you want to know more about IPM, you can call the Butte County Master Gardeners at (530) 538-7201.  You can also read more about IPM by visiting the UC Davis IPM website: www.ipm.ucdavis.edu.