Don’t stress out unnecessery over “who’s who” in the garden: Separate your good guys from the bad guys. Often, the details are not obvious enough to guess on your own. An accurate ID chart is a revelation. What’s key: That means distinguishing between native species and actual pests, the former being a neighbor you want to protect (and definitely not worth spraying).
The visual guide help you avoid treating every generic-looking green larva as something to kill, since they often comes in many different colors, shapes, and even host-plant clues, like this: If it’s a bright-green critter with white V’s on the tomato plant, chances are it’s a fast-moving pest, and will strip its leaf in no time. But if such a green insect is dining on parsley or dill, well, then it’s more likely a swallowtail species, worth protecting with all your might.
How to Identify Garden Pests and Beneficial Insects
That’s where knowing host plants; the easiest clue if you’re stumped, can come into play. Many caterpillars are specialists that eat just one type of plant or at least a few. That means it narrows down the list of suspects much more faster then if you had to remember all their body patterns. This is a biological handicap that help us.
For example, if you see some larvae chowing down on milkweed, you know those are monarchs, so relax and enjoy the view. The same goes for painted ladies: seeing them on thistles usually means it is that species of butterfly, which does not cause any harm in most vegetable bed. Knowing who eats what makes management more precise, not panicked.
Another big factor: Colorado is just plain high… And its elevation changes mean you can expect some variation in what shows up along a hiking trail or in your own backyard. Because the state has such dramatic changes in height, it produce very specific areas of habitat that in turn support their own community of insects. If you’re down in the lower plains, for example, you’ll see more agricultural pests like cutworms and armyworm than you will in the Montane and Foothill regions. Those regions tend to favor certain tree types (cottonwood and aspen), respectively, and other species that does well in those particular environments and cool weather. So if you garden in Telluride, for instance, instead of Denver, the latter may not fully apply.
Don’t overlook safety! Some of the larvae in this area possess irritating hairs or even spines (that sting). These will produce an uncomfortable reaction for us humans. You’ll notice that these few “problem” species stand out in bold in the chart; they range from those that cause mild irritation to those that is venomous. Knowing this avoids unwelcome discomfort while also training you to look but not feel if you’re not sure what it is. It is always best practice to pick up unknowns with your gloved hand, a stick, or something similar instead of your bare fingers, no matter how harmless they looks.
Fortunately, many of these tactics are not heavy-handed with chemicals, because naturaly methods of management generally prove more effective in this situation as well. Biological control (such as Bt) targets specific pests instead of harming the beneficial insects that help keep the ecosystem healthy and balanced. Physical controls (like floating row covers) block adult moths from reaching vulnerable crops where they might lay their eggs. If you take specific action with an eye towards early detection, you’ll save your crop…and support the amazing population of moths and butterflies we have around Colorado that help our landscape glow.
The next time you come upon a hole in a leaf, take a moment before whipping out the treatments. Examine the markings closely. Note the elevation zone where it occurred. Check the host plant. Knowing what you’re looking at changes the whole story about that interaction. Maybe a potential enemy is really one of your best neighbors, just waiting to turn itself into something great.