Whats eating my plant?

Critters are everywhere and I don’t just mean the rabbit, ground squirrel, mole, vole, deer and bear kind. I mean insects. I thought I had enough problems with the mammalian pests until the insect pests arrived. First, there were aphids, then ants, now grasshoppers, squash bugs and tomato hornworms, to name just a few!

Are insects also bugging your plants? How do you manage them? Insect pests, such as ants, elm leaf beetles or boxelder bugs, can be annoying, while others may be damaging (aphids, hornworms, caterpillars), a health concern (ticks, bedbugs, mosquitoes) or a cause for fear (black widows). The good news is that relatively few insects actually cause significant injury to plants.

Most plant problems are caused by non-living factors. These include weather, wind exposure, lack of water or excess water, soil type, soil compaction, poor drainage, improper plant selection for the site, restricted roots or poor cultural practices.

When you want to solve a suspected insect problem, here are some things to consider:

  1. Be sure to accurately identify the plant and the cause of the problem. Sometimes it is not an insect problem, even though insects may be present. And, the insects you see may be beneficial insects that help control pests!
  2. Look at the signs and symptoms of damage. Could they result from one of the non-living factors mentioned above?
  3. How many insects are there? Can you tolerate this level of damage or blemish if they are not seriously harming the plant?
  4. What is the overall health of the plant? Weaker plants might need help, while a healthy plant may be left alone.
  5. Is the problem unlikely to go away if you don’t take action?
  6. What insects or other pests are commonly found on this type of plant? For example, dogwoods and ash trees are known to be aphid magnets, but seem to survive intense aphid infestations and rarely require treatment.
  7. Are there beneficial insects present that might help slow or eliminate the problem insects? Ladybugs and lacewings are aphid predators. The larvae of these insects can look scary, though, so be sure to learn to identify all the life stages.

If you need help identifying a plant problem, University of Nevada Cooperative Extension has trained Master Gardener volunteers and horticulture staff to help you. Capture a number of the insects, put them in a sealed bag or jar, and bring them and a plant sample showing damage to your local Cooperative Extension office. Another option is to send us a series of photos showing what is going on with a plant, including shots of the area around the plant. When you need unbiased research-based information, contact your Cooperative Extension office – Reno, 784-4848, Carson City, 887-2252 or Minden/Gardnerville, 782-9960. You can also submit questions and send photos to mastergardeners@unce.unr.edu. Or, check out Cooperative Extension’s horticulture website: www.growyourownnevada.com.