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The P&PDL Picture of the Week
for 24 March 2003



Tree Decline

Karen Rane, Plant Disease Diagnostician, Department of Botany and Plant Pathology, Purdue University

This photograph shows two flowering cherry trees. Although the trees were planted at the same time, and are the same variety, they are not identical in appearance. The tree on the left is showing several symptoms associated with the condition called tree decline. The foliage is yellow-green, the tree is smaller in size and the crown is thinner, with less foliage and fewer secondary branches than the tree on the right. Trees in decline may also show shorter annual twig growth, smaller leaves and death of twigs and branches. Tree decline usually develops over the course of several years, and is usually due to the effects of adverse environmental or cultural conditions on tree roots. Stress factors that contribute to tree decline include drought, excessive moisture, poor soil drainage, root injury from construction activities, and the accumulation of deicing salts. Trees in decline are more susceptible to opportunistic pests such as insect borers and fungal canker diseases. It is extremely difficult to reverse the effects of root damage in a declining tree. Taking steps to reduce stress factors by protecting affected trees from construction activities and irrigating during periods of drought may help to slow the progression of decline symptoms. However, the best management for tree decline is prevention. Choosing the best tree for your particular site, avoiding any site disturbances once the tree is planted, and maintaining the health of the tree through proper watering and fertilizer applications are critical steps to avoid decline in trees. For more detailed information, check out Purdue University extension publicaton BP-37-W, entitled “Tree Decline”.

Click on the small image to view a larger image.

Two flowering cherry trees
in front of Lilly Hall

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Last updated: 25 March 2003/amd
The Plant & Pest Diagnostic Laboratory at Purdue University