Master Gardener: Integrated Pest Management Offers Options
Last updated 7/16/2018 at 2:46pm
Integrated pest management, or IPM, is simply understanding the various options and methods of pest control and choosing the most appropriate one for each particular situation. This is counter to the common practice of simply dousing the garden with chemicals at the first signs of any insects or damage.
One important concept in IPM is “threshold,” or your tolerance for some crop damage caused by insects. You may feel that “zero tolerance” is your goal, but be realistic. Mother Nature will never allow the annihilation of all insects, and does it really make sense to spend $20 on chemicals to obtain $10 worth of vegetables? IPM is all about using a simpler, less expensive method of controlling insects while still enjoying a good harvest. The various methods of pest control include: cultural, mechanical, biological and chemical.
Using good cultural methods of gardening goes along with the concept that keeping your plants healthy is the first line of defense against pests. All crops need good soil in which to thrive. Test your soil each year and amend your garden with fertilizer, if required, as well as plenty of compost and/or other organic matter. Most vegetables require at least eight hours of sun a day, so plant in an appropriate area. One inch of rain per week is optimal, so water as needed. Choose plant varieties that are pest resistant and are suited to your area. Crop rotation, timing and spacing are other important cultural practices. Using squash as an example: plant them in a different area of the garden each year; don’t clump plants together – spread out their placement; also spread out the timing of planting (put some out early enough to enjoy a harvest before the vine borer arrives and another planting later in summer).
Mechanical means of insect control can be as simple and inexpensive as picking beetles off your plants and destroying them. Placing metal bands or “collars” around seedlings will minimize damage from cut worms. Bird damage can be controlled with the use of screens, while floating row covers are quite effective in keeping insects away from vegetables. Keep in mind that row covers also keep out the pollinators as well, so use only on vegetables that do not require pollination for production of their fruit. Trapping is another mechanical means of pest control. Many traps are available at local stores or through garden catalogues. They may work well, but are not always cost effective for use in the small kitchen garden.
The next category of pest control is biological. This can include using microbial insecticides and/or using beneficial predator insects to minimize pest damage. Microbial insecticides are not chemical and may be used on an organic garden. They are generally specific to one particular pest and pose less of a risk to humans and the environment. The most common is bacillus thuringiensis, or Bt, which is used to control cabbage moths. You would probably recognize the brand names under which Bt is sold, but, if not, just check the label or ask for assistance at the garden supply store.
My personal favorite method of pest control is the use of beneficial predator insects to keep the pest population under control. The concept is to mimic nature as much as possible by using the natural pest predators to keep the population in balance and therefore minimize damage. It is very important to remember that not all insects are bad guys. Insects beneficial to your garden include lady bugs, lacewings, wasps, syphid flies and the praying mantis. These guys kill the bad bugs that are damaging your crops. It is possible to purchase beneficial predator insects, but not recommended. It works much better to simply provide a habitat that will attract them (if you plant it, they will come). Certain flowers and herbs will draw these good insects to your garden. Examples of herbs include: sage, dill, fennel, parsley, basil, oregano and mint. Flowers that attract beneficials include: nasturtium, poppy, zinnia, marigold, aster, daisy, coneflower, bee balm and cosmos. You can spend a lot of time and effort learning to identify the bad insect, determine its predator and choosing the specific plant to attract it. Most of us honestly don’t wish to do that much “homework.” I’ve had quite a bit of success simply by planting a wide variety of vegetables, herbs and flowers all together to create a mini “eco-system” in my garden. On a side note, when I told my mother about this “new” concept of beneficial predator insects, she just smiled and replied that my grandmother had always grown nasturtiums, cosmos and many herbs in her garden. It would seem that recent research is proving that some of those “old wives tales” were accurate. In addition to natural pest control, you will enjoy having beautiful flowers and aromatic herbs in your garden.
Finally, if all else fails, chemicals are an option – unless of course you choose to grow organically. Try to use chemical controls that are specific to your pest problem, that degrade quickly thus causing less environmental damage and that have a lower toxicity to humans and animals. Some examples of these include insecticidal soaps and horticultural oils. Use synthetic pesticides only as a method of last resort.
Most importantly, remember to read the directions and cautions carefully and follow the directions exactly including wearing all appropriate protective equipment.
(If you have gardening questions, visit the Extension Master Gardener Volunteers at the Transylvania Farmers Market on the first and third Saturday of the month from April through October. For more immediate questions, information about becoming a Master Gardener or suggestions for future articles, call (828) 884-3109 or email [email protected] ncsu.edu and include Master Gardener Question in the subject line.)