Diagnosing a plant problem before taking action is critical to success

Many years ago, while working at the garden center in the 80’s, people would bring in plant samples looking for a “spray” solution. Oftentimes, the first request was, “I need something to spray on my ‘xyz’ plant.”

Back then, I would likely have recommended a pesticide to eliminate the problem. Sometimes, without diagnosing the problem, and sometimes just making a guess.

This was before my Ohio State University Extension career starting in 1992, where I learned more about plant problems and diagnostics. I also learned about the disease triangle and the life cycle of pests, and how important these were in determining an ecologically-friendly but useful solution. Now I am much wiser; well, let’s say more educated!

To determine a plant problem, identify the plant first, and then research common problems for the plant. Plants tend to have common problems that affect them.

Let’s use roses as an example. You notice the leaves on your roses are turning yellow and dropping to the ground. They have black spots on them as well.

Use the internet to research common problems with roses. I always recommend using the .edu extension to get the most accurate, research-based information.

You will find that common problems include aphids, Japanese beetles, sawflies, black spot, rust, powdery mildew, and rose canker. Rose rosette disease has been added to the list in recent years.

You now have a much narrower list to work from than guessing what might be wrong. Going through this list, you can read about the symptoms and their causes.

In many cases, you can determine the problem with these simple starter steps. However, if you aren’t finding the problem, you may need to dig a little deeper or ask for help. Don’t guess and use pesticides until you are confident in the diagnosis. In some cases, pesticide treatment may not be necessary.

Remember that there might be other issues coming into play as well. For instance, a specific problem may have been caused by or exacerbated by weather or other environmental conditions, etc. It is not always clear-cut, but this process helps to narrow down the culprit.

Once you determine the problem(s), university fact sheets can be extremely valuable as they provide IPM options. I always recommend university fact sheets over other resources found online. These are accurate and contain research-based information.

These fact sheets give options for managing the pest in question. They provide the three main strategies in IPM: cultural, biological, and chemical options. You then decide which works best for you.

Diagnosing plant problems has gotten easier with the use of Artificial Intelligence (AI). However, keep in mind there are advantages and drawbacks to using AI. Use AI to help generate a list of common problems with plants.

Next week, I will discuss cultural, biological, and chemical strategies and provide examples of how to use them.