For three hours, the group of 44 students studied how to detect plant diseases and learned to identify insects that can wreak havoc in your yard. Offered by the University of Tennessee's Extension Office, the third of the 12-class series featured UT plant disease specialist Tom Stebbins and insect laboratory assistant David Cook. They came prepared with a comprehensive slide presentation and samples of everything from dogwood leaves covered in powdery mildew and Bradford Pear branches crisped by fire blight to bag worms and pine sawflies. Diseased roots are dark, reddish brown. Sometimes, these can be trimmed off.
Healthy roots are white.
To avoid further problems, plant in well-drained soils or raise your beds up. Look for young twigs or the ends of branches that appear scorched and are usually in the shape of a shepherd's crook. Bradford pears, roses and crab apple trees are some of the susceptible plants. Stebbins recommends pruning dead branches and then spraying with antibiotic or copper fungicides. However, always read the label carefully, he says.