Download “ What’s Wrong with My Plant”? Helping Master Gardeners Help You

“ What’s Wrong with My Plant”?
Helping Master Gardeners Help You
By Ron Johnson, University of Illinois Extension DeKalb County Master Gardener
Identifying what is wrong with a plant can be a complete mystery to some
people. Others believe any problem will be solved by an application of
insecticide no matter what is the cause. In order to correct plant
problems, the cause must be identified correctly. Applying an insecticide
on a tree with a fungal disease will not help. First identify the plant down
to the cultivar if possible. Each plant has a set of growing conditions which
must be met for it to thrive, plus it may have insect pests and diseases
which also cause problems. Next determine exactly what you are seeing
that is abnormal. Symptoms are changes in growth or appearance by the
plant in response to a damaging factor. This might be slow growth, off
color or wilting leaves. Signs are evidence of the damaging factor. You
may see the actual insect, fruiting bodies of a fungal disease or bacterial
ooze. In the case of problems caused by abiotic issues, you might see an
old wire wrapped around the trunk of the tree or see the tree has been
planted six inches too deep! Now check out the environmental conditions.
Is the soil well drained? How many hours of sun does the plant get? Are
the pH and nutrients appropriate? Last on the list is look for a pattern of
damage. Generally speaking, random damage that spreads is usually
caused by a biotic problem such as insects, fungi or bacteria. Uniform
damage that occurs once and does not spread especially if it is occurring
across a multitude of kinds of plants is usually caused by a non-living issue
such as poor drainage, chemical or frost damage. Careful observation of
signs and symptoms will allow a Master Gardener to answer your questions
accurately and often quickly.
Main Points
• Identify the plant
• Determine what is abnormal (compare to healthy); what seems to
be the primary problem?
• Look for symptoms (response to a damaging factor, changes in
growth or appearance) and signs (evidence of damaging factor,
fungal fruiting bodies, bacterial ooze, insect skins, webbing, exit
holes, honeydew).
• Check the environmental conditions (water, soil, pH, sunlight,
temperature, fertilizer, pesticides, neighbors plants), injury.
• Is the damage random or uniform on the plant?
• Use books, internet, or University of Illinois Extension DeKalb
County Master Gardener’s Hort Help Desk (815) 758-8194.