In The News

Weather and Needle Loss in Conifers

June 17, 2019 by Hugh Darlington, Board Master Certified Arborist
Douglas Fir showing signs of Swiss Needle Cast.

In wet weather, a fungus can more easily infect the needles of the trees for an extended length of time. The temperature and air moisture level are two factors present during the spring growth period that determine how well a fungus will grow, and the severity of an infection for each tree. Even when the disease is present, your trees may escape long- term damage if both factors are not ideal for fungus. For example, if temperatures are higher or lower than the fungus requires, the disease may have no effect on the needles. Or when the moisture level is not conducive to grow the fungus, the needles can be safe even if the temperature is correct.  Some years, the weather stays perfect for the fungus longer than usual, and the disease can just keep on infecting the needles.

There are several fungi that can attack different needle parts of the tree. Many of them can be treated with the correct fungicide (spray material). But there are some fungi that have no real treatment measure. In these cases, early and proper diagnosis is paramount in preventing or halting the disease. 

Douglas Fir showing signs of Diplodia Tip Blight.

Often, when a client calls for an evaluation, the time needed to send the sample out to a lab for diagnosis can delay the health of the tree.  

So don’t be shy. If you think needles are being lost prematurely and you would like a professional to inspect your conifers, call our staff immediately. We’ll  get you the diagnosis and explain what if any, corrective measures can be taken. Early intervention can make all the difference. 

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