Self-diagnosing some of your plant problems

By ERIC BARRETT

OSU Extension Educator

Observation is the most-important thing you can do in the lawn and garden.

At our clinic, we receive several plant samples at the final stage of infection. At this stage, diagnosis is difficult. Thus, we may be able to provide only a list of what may have caused the demise of the plant.

Plant diseases rely on the disease triangle in order to infect plants. The disease triangle has three sides – the host/plant, the causal organism/disease and the environment in which the plant is living. Diseases can be minimized or stopped based upon change or elimination of any one of these three sides of the triangle.

Can you change any of these?

First, let’s talk about the plant. The plant is the “susceptible host.” For example, in nature, dogwood trees are an understory tree. They grow under and at the edges of the larger trees in the forest. So, is it a good idea to plant them in full sun? You need to select the right plant in the first place to fit the site in your landscape.

Next is the causal organism – the pathogen that infects your plant. Disease is everywhere. It simply takes advantage of the right plant in the wrong environment.

Finally, there is the environment. This is not the overall environment, but the environment in which you plant. As humans, we provide poor environments for many plants.

So, what can you do?

Make a plan. Don’t just purchase a plant because it is beautiful or cheap. Know that it will like to live where you plan to put it in your landscape.

You can choose the right zone. We live in zone 5. Even though we are near the edge of zone 6, we have several winters that make it tough for zone 6 plants to thrive.

Choose salt-tolerant plants to grow along the road and driveway. Diverting water from the downspout may be a solution to an unhappy shrub. Moving a plant may be the best solution, rather than treating it for a disease.

For details on the plant disease triangle, go to: http://go.osu.edu/diseasetriangle