Tree Pest Alert for August 27, 2012 – Iron Chlorosis

This is a good time of year to be identifying trees that suffer from chlorosis because the symptoms are very visible right now and the treatment time is just around the corner.  Use the information below to help identify trees suffering from chlorosis and learn how to manage it.  But first, what exactly is chlorosis and why is it a problem for trees?

What is Chlorosis?

Tree Suffering from ChlorosisChlorosis is a serious issue of shade trees where the plant is unable to properly manufacture chlorophyllChlorophyll is an important leaf component which is responsible for energy absorption for the entire tree.  Trees without enough chlorophyll will not be able to grow and live.  If this condition is not corrected, the tree will eventually die. 

The causes of chlorosis are complex and not entirely understood, but as a general rule, it is caused by the lack of a micro-nutrient or combination of micro-nutrients that a tree needs to manufacture chlorophyll.  Iron and manganese are the common micro-nutrient deficiencies that cause chlorosis in shade trees.  These minerals are often not lacking in the soil, rather a condition exists where the tree’s root system is unable to obtain them in usable forms. 

The information that follows specifically refers to iron chlorosis.

What trees does iron chlorosis affect?

All shade trees are susceptible to chlorosis, but some species are more commonly affected than others.  Species commonly affected by iron deficiencies include:

What symptoms should I be looking for?

margin: 4px 26px 4px 0px;"> Photo of Tree Showing Symptoms of Chlorosis
  • Yellowing in between veins on newer leaves
  • Brown, dead areas developing on leaves suffering from chlorosis
  • Tip dieback and decline on severely affected trees

What can I do about it?

The overall management strategy for chlorosis should address the underlying factors that cause chlorosis.  A single application of Verdur® will provide up to 3 growing seasons of green leaves, but consider other treatments like pH adjustment of soil, decompaction, and practices that stimulate root development.  Contact The Tree Geek™ to learn more about these other treatments.

Verdur® is applied through a process called macro-infusion.  This process involves drilling small holes every 4-6 inches around the base of the tree.  A pump system is then hooked up to these holes and a solution of Verdur® and water is pumped into the tree. 

Applications should begin about 2 weeks before anticipated leaf drop in the autumn and can continue until the daytime air temperatures get below freezing.

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