To Treat, or Not to Treat

Written by: Luke Volbrecht, ISA Certified Arborist WI-1112A

Posted: 2022 | Disease Treatment | Spring

That is often the question, and there is not always an easy answer. For some pests and diseases affecting trees, the answer is absolutely yes! if you want the tree to live (Emerald Ash Borer and Ash trees are a prime example). Other trees such as Austrian Pine and Colorado Spruce, which are affected by Needlecast Diseases, it becomes more of a judgement call. The question primarily becomes: how important is the tree to you and your landscape?

Treated vs. Untreated Spruce

If you have seen a mature “Pine” that appears thin and dying from the bottom up, then you are likely seeing the effects of needlecast.  This disease causes older needles to drop prematurely and impacts the tree’s health and appearance. The damage from the disease isn’t typically noticeable to a property owner until much of the tree canopy has been affected. Even at an advanced stage, it can still be possible to save a tree infected with needlecast. There are treatments which protect the new needle growth each year to begin recovery. Over time the tree will retain more of its needles, improving both its health and appearance as it recovers. But again, it must be asked, how important is the tree to you and your landscape?

Austrian pines typically respond much quicker to treatments with an improved appearance within two years. This is because many pines only hold two to three years’ worth of needles at any time, this is perfectly normal for them. A healthy spruce by comparison will typically hold 5 to 7 years’ worth of needles on its branches. This means that a spruce can take 3 to 5 years or more to recover depending on the disease severity. That length of time and investment should be understood going into the recovery process for these important trees that are a centerpiece for the yard or that provide significant benefits such as screening along a property line. Other spruce that are in heavy shade, crowded by other trees, or growing under electric wires might not be the most worthwhile candidate for treatment.

Please note, Needlecast treatments are only effective if they are applied yearly and should not be skipped if you want the fullest benefit from the application. Depending on your timeframe and goals, treatment may be the best option for your trees. Other times, replacing trees with disease resistant species may be the better option. Your Wachtel Tree Science Certified Arborist is ready to help guide you through your decision process!