Key Features
- Poor growth
- Yellowing or early fall color
- Defoliation and canopy dieback
Symptoms
Symptoms of decline include poor growth, yellowing or early fall color, heavy seed crops, defoliation, and dieback. Look for signs borer insects or cankers or root rot caused by opportunistic pathogens.
Biology
Decline is a term used to describe the combined effects of a condition that slowly weakens the tree, predisposing it to insect or pathogen attack. Inciting events like drought or flooding, coupled with weak opportunistic insects and diseases that only attack weakened plants contribute to the decline and death of the tree over several seasons.Some conditions that slowly weaken trees include sites with compacted soil, regular exposure to road salt, poor soil pH, iron chlorosis, etc. Brief, severe stresses can be drought, flooding, or severe defoliation due to insects or pathogens. Contributing factors include opportunistic borers, root and butt rots, or canker pathogens. Declines are complex in the variety of interacting factors and it is difficult to identify all the minor factors that may have resulted in the specific tree problem.
Management Recommendations
Always select trees that will thrive in the selected location, taking care to minimize external stresses by providing the needed space to grow, minimizing the risk for compaction due to construction or hardscape, surrounding use, etc. For trees already experiencing decline, identify and relieve as many stresses as possible. Water trees thoroughly during periods or drought; mulching around the base of trees will decrease water loss from the soil. Lightly fertilize trees as needed.Tree decline is complex of interacting factors and require that each minor factor be addressed to avoid the additive effect that results in decline
Effective Pesticides
Pesticides are neither available nor recommended for managing this condition.
Resources
- Not satisfied with ID? Contact the Purdue Plant and Pest Diagnostic Lab
- Sign Up for the Purdue Landscape Report
