Integrated Pest Management (IPM) is considered the best approach to minimizing pest damage in the landscape. IPM is not synonymous with organic gardening but it does strive to minimize pesticide use by utilizing multiple pest control methods.
Know the enemy. The IPM process begins with pest identification. What exactly is threatening to injure your garden? Evaluate the amount of damage, then decide if control is needed. Sometimes transient pest problems do no real injury to vigorous plants and are best left to resolve themselves.
Unacceptable insect damage
If the gardener decides that pest control is necessary, multiple controls are usually best. There are four general categories of control methods: cultural, physical, biologic and chemical.
The first, cultural, means using practices which promote robust plant growth and minimize opportunities for pests to become problematic. Certainly one could fill a library on this subject, so I'll offer only a few examples. Mulching prevents weed seed from getting to the soil and light from reaching the emerging weeds. Everything we do to improve the soil promotes healthy plants which can resist pests. Correct watering practices and crop rotation can prevent disease and insect problems. When disease is a primary concern, chose disease-resistant cultivars.
As for physical controls, to paraphrase one plantsman: "We can fence the critters out or coop up the critters." In other words, we can use barriers such as fences or row covers to keep pests away from the plants, or we can remove the pests from the garden. In the illustration, I am removing Japanese beetles from roses by knocking them into a container of water laced with dish detergent. One of my neighbors uses the opposite strategy. All of her roses are covered in net bags.
(Photos: Right: Pick Japanese beetles off in the early morning when they are torpid and drop into soapy water. Below: There are zero reports of survivors.)
But there are only so many bugs you can pluck. Fortunately, weeding is one of my favorite gardening activities, but I can't say I'm that fond of physically removing pests other than weeds, so I depend on "biologic" controls, the third control. to get the job done.
Deprive pests of life's essentials: food, water and a place to live.
Exploit predators. There are always far fewer of these than there are plant eaters, so every pesticide application kills a greater percentage of beneficial insects than plant-eating pests. It takes longer for the good guys to recover. Research has revealed that gardeners make the overall problem worse through routine insecticide applications. A healthy population of beneficial insects keeps potential pests in check.
Finally, chemical control: There are times when a pesticide application may be necessary. Read the label carefully to make sure that the product is intended for the problem. Follow application directions to the letter. Use the least toxic chemical possible. Every container label indicates the level of toxicity: Caution, Warning, or Danger. The most toxic carries the Danger designation.
The final phase in the IPM process is evaluation. Are pest populations or damage at an acceptable level? Which controls were most effective? Is there a new problem? If so, begin the process again with pest identification.
Master gardener Ann Bartlett never lets lack of familiarity with a plant stop her from trying it in the ornamental beds around her home.