The Greener View: Diagnosing Plant Problems | Jeff Rugg | Columns | ArcaMax Publishing
Jeff Rugg on Oct 6, 2021
A: I tell people all the time that there are only three things that affect plants: insects, diseases and everything else. Dead grass looks like dead grass, but we often have to be detectives and coroners to figure out the likely cause of the problem.
The key to diagnosing many plant problems is performing regular inspections. If you know what a healthy plant looks like and you are regularly looking at your plants, you can see the problem as it develops. While the problem is growing, there will be signs and symptoms left by the insect or disease. When looking at plant problems, signs are directly visible evidence of the cause, such as a part of the fungus or insect. Symptoms are visible effects of the problem, such as wilting, yellowing or branches dying.
Sometimes the problem is hard to diagnose. Take the problem at hand: dying grass. We are looking at only half the plant that is above the ground. It wilts, turns brown and looks dead. The top can't survive if the roots are dead, dying or missing. If grubs ate the roots, then the top will turn brown and die. If a root rotting fungus kills the roots, the top turns brown and dies. If the soil is only a couple inches deep, as in many yards, there aren't enough roots to supply water in a dry spell, so the top turns brown and dies. So, an insect problem, a disease problem and an "everything-else category" problem all caused the symptoms of the roots dying first, followed by the top of the grass.
A dry summer this year has harmed a lot of trees that are going to go dormant soon without having stored as much water as usual. If the winter has drying winds and bitter cold, then the tree may have problems growing next spring. The tree may grow in the "survive" range and not the "thrive" range next year. Trees that are not doing well are more susceptible to borer insects. The tree may die in a year or two, but the damage started this summer. When the tree dies, who will blame the dry summer this year?