Colorado gardeners deal with a changing list of weeds and pests, including dandelions, bindweed and Japanese beetles.
While itap tempting to use pesticides, experts recommend a smarter, safer, and more sustainable method called Integrated Pest Management (IPM).
What is Integrated Pest Management?
is not only about using fewer chemicals. Itap about changing how you care for your garden.
“Chemicals have a place in IPM,” said Cassey Anderson, CSU Extension horticulture specialist in Adams County.
“But the goal is to minimize their use by combining cultural, mechanical, biological, and, when necessary, chemical controls.”
Here are some ways to use IPM in your Colorado garden.
Prevention: The first line of defense
The healthiest gardens rarely need pesticides.
Proper mowing, fertilizing, watering, and choosing the right plants are all critical.
For example, mowing your lawn high and fertilizing it well can help crowd out dandelions. Watering at the right times and aerating the soil can help prevent diseases such as Ascochyta leaf blight and fairy rings.
Turf choices matter: “Tall fescue or buffalo grass use less water and are more resistant to pests,” said Karim Gharbi, a CSU Extension horticulture specialist in Denver.
can help you switch to native grasses or xeriscaping. This reduces both water use and pest problems.
Cultural and mechanical controls
Before reaching for products, try simple tactics:
- Pull weeds by hand when they are young, and their roots are still shallow. Tools like a stirrup hoe work well for young weeds.
- Control fungus gnats in houseplants by letting the soil dry fully between waterings. The pests thrive in moist environments.
- Proper irrigation can prevent many problems. Gharbi suggests conducting an irrigation audit: set out cups, run your system, and check if the water is distributed evenly.
Biological controls
Nature offers powerful allies:
- Bacillus thuringiensis (Bt): This bacterium targets the digestive systems of specific insects like mosquito larvae (in “mosquito dunks”) and cabbage loopers, without harming beneficial insects or humans.
- Bindweed mites: These tiny arachnids, available from , can help suppress bindweed in unirrigated areas.
- GrubGone! Contains a bacterium deadly to Japanese beetle larvae, a growing lawn pest in Colorado.
Biological controls work best when they match the pest species, so always identify your pest before taking action.
Safer chemical options
Sometimes you may need to use a pesticide. If so, choose safer options and use them carefully:
- Horticultural vinegar: Only commercial, high-strength (30 to 45 percent) vinegar works as a weed killer. Kitchen vinegar (5 to 10 percent) is not strong enough. Even with strong vinegar, it usually only burns the top of the plant and rarely kills the roots.
- Essential oils: Some products with peppermint, clove, or pine oil can mildly repel pests, but they usually do not work well against established pests.
- Avoid neonicotinoids: Products with imidacloprid and similar chemicals can harm bees and pollinators, so avoid them.
Critical safety steps: Always read the label before you buy, use, or dispose of any product. Wear protective gear, especially with strong acetic acid products. Remember, using more is not better.
Know your pest and your threshold
Not every bug or weed needs treatment.
“A single Japanese beetle grub isn’t a crisis,” Gharbi said. “Lawn thresholds are usually 6–8 grubs per square foot.”
Learn to recognize the damage and decide how much you can tolerate. Sometimes it is better to let some pests or weeds stay, especially if the weeds provide pollen for early-season pollinators.
Consult an expert before you act
Both Anderson and Gharbi recommend calling your county extension office or Master Gardeners before taking major action.
“We see a lot of unnecessary pesticide use,” Gharbi said. “Often, the real issue is irrigation or turf health.”
County agents can help you identify your problem and choose the best way to manage it. This can save you time, money, and effort.
Final thoughts on pest management
Safe pest management in Colorado gardens starts with healthy practices: proper plant selection, watering, and soil care.
Mechanical and biological controls can manage most pests. If you need chemicals, choose the least toxic option and always follow safety instructions.
Remember, a healthy, diverse garden is your best defense.
For questions or site-specific advice, contact your local extension office.
Sara B. Hansen is a Denver-based freelance writer.
