For most trees, only the needles near the twig tips are infected. 2015 Winnipeg Free Press. Nevertheless, in order to compensate, the tree creates a self-induced deficiency of potassium (K)to older needles by translocation of K to the newest growth needles. Containers of Colorado Spruce within a nursery container bay that the grower stated were over irrigated during the summer. Occasionally,observations of White Spruce(Picea glauca) or Colorado Spruce (Picea pungens) within landscapes, nurseries, & Christmas tree farms will show current needle growth having a blue or blue-green color, but with older, inner needles having lost the desirable color and turning pale or even yellow. Colorado Spruce showing symptoms of undesirable discoloration of older, inner needles. The same symptoms at some locations may occur periodically during very wet seasons that trigger occasional flooding. Stated in other words, when the roots cannot uptake additional K from the soil, then the new growth receives priority. Immobile elements such as calcium (Ca) do not readily translocate and hence, deficiency symptoms will be observed initially in the upper, new plant tissues. Photo by SK Rettke of RCE. All Rights Reserved. Posted/Updated: Compromised root systems result in nutrient deficiencies within the spruce and sometimes, more specifically, the inability of roots to uptake Potassium (K). Needles that turn brown will fall off. Unfortunately, there is little that can be done to alleviate problems from poor planting or a poor site. Photo by SK Rettke of RCE. Although the reasons for such symptoms can be from a complex number of conditions, a compromised root system is typically the underlying cause. The twigs with the yellowish green needles are usually curved or slightly bent. If this article is to be used in any other manner, permission from the author is required. QUESTION: I noticed that the needles on my spruce tree are turning a yellow-green. Photo by SK Rettke of RCE. If you do not see new buds in July and August, then the twig is dead. Improper dormant oil application or potassium (K) induced deficiency? This article was originally published on April 4, 2007. We occasionally receive spruce samples in the Plant Disease Clinic that show yellowing of the needles, sometimes only older needles and sometimes both older and younger needles.
Most likely, fertilization with potassium (K) will not solve the problem because the cause is from root stress and not a shortage of potassium in the soil. 2011-06-11. Ames, IA 50011-2031 Copyright 2022ISU Extension and Outreach Injuries to the trunk or roots can also cause these symptoms. In most cases I discovered that this is a result of spruce tip blight, a fungal disease infection. Usually this is a minor disease in spruce; however, in 2010 and again starting out this year I have seen nearly whole trees with yellowing needles.
After a wet summer with a period of high humidity, the needles, especially near the tips of the twigs, turned yellow or yellow green. It started last summer. Also, over time, the blue or blue-green waxy bloom on the older needles can be partially removed by natural weathering. Problems with planting are also a common culprit. Spraying the entire tree at least twice 10 to 14 days apart in June with copper fungicide is a recommended control for this disease. The yellowing or off-color of older, interior spruce needles are most likely symptoms of trees having root system problems. The pale or yellowed older needles often never fully return back to their previous coloration even after soil conditions are corrected or become more optimal. Unless they are correct, some cynical clients may even make claims that their tree care company sprayed dormant oils on their Colorado blue spruce and caused the loss of the blue color on the older needles. White & Colorado Spruce cultivars with excellent appearance growing in a Christmas tree farm at a elevated location. Generally, the flow or transport of potassium (K) is primarily to the new growth. Photo by SK Rettke of RCE.
The blight can re-appear on other twigs later in July or August, so a third or fourth spraying may be necessary. Furthermore, highly acidic soil pH can be a factor. When Should I Spray Conifers for Needle Diseases. This spring is shaping up to be a damp one in southern Manitoba, and I am already seeing an increase in this problem developing. (800) 262-3804, Iowa State University|PoliciesState & National Extension Partners, by Christine Engelbrecht, Plant Pathology, Like us at Plant and Insect Diagnostic Clinic, Like us at Department of Plant Pathology and Microbiology. The scientific name for the disease is Sirococcus conigenus. However, first eliminate other causes such as spruce spider mite stippling symptoms or dormant oil applications that may have removed the waxy glaucous bloom growth on needles. Yellowing of spruce may be caused by a variety of noninfectious stresses, particularly problems with the roots. The information contained within may not be the most current and accurate depending on when it is accessed. The limited K is now taken from what is available in the older needles and donated to the new growth.
For more information on spider mites on conifers, see this article. Hence, the two-tone coloration of blue/green new growth needles vs. pale to yellowish old growth is created. Rutgers University | New Jersey Agricultural Experiment Station | Pesticide User Responsibility. Such problems can include being planted too deep, which can lead to development of coiled girdling roots around the trunk, or being planted with synthetic burlap or wire intact over the roots or stem, restricting free growth. The stress of roots growing in anaerobic conditions produced by wet or saturated soils will cause of the symptoms since the movement of soil minerals into and across plant cell membranes requires oxygen. This may not easily be solved in lowerareas with soils having a high clay percentage. It is important to note that studies have shown excessive nitrogen (N) fertilization within soils that are in fact potassium (K) deficient can even further limit the uptake of this nutrient. Links to this article are strongly encouraged, and this article may be republished without further permission if published as written and if credit is given to the author, Horticulture and Home Pest News, and Iowa State University Extension and Outreach. Applying fungicides, insecticides, or fertilizer is unlikely to help the situation. This is a sure sign of the disease. Such stresses include problems with the site, such as too wet or too dry a site, or excessively compacted soil. Readers should refer to my Oct. 9, 2010 Tree Care article on the proper fertilization of trees for more information. Sometimes symptoms can become dramatic and initiate both aesthetic and plant health concerns.
An overall yellow appearance on spruce may also be caused by spider mites. Can you tell me what I can do about this? Such symptoms are rarely a result of infectious disease. Similar to K, nitrogen (N) is also a mobile element and can readily translocate from older to new plant tissues. Photo by SK Rettke of RCE, Colorado Spruce species showing the desired uniform blue coloration to both new & older needle growth. If rain occurs within 24 hours of spraying, the treatment will have to be re-done as rain will wash off the fungicide from the needles and twigs. Photo by SK Rettke of RCE, Although a Fir & not a Spruce, the older needle discolorations are stippling symptoms from spruce spider mites. Although excessively dry soils have also been implicated as a potential cause, most commonly, spruce trees growing in excessively wet soil conditions will be the reason for the symptoms. Also a Magnesium (Mg) deficiency may be involved as well. These problems emphasize the importance of starting with an appropriate site for a tree, and planting the tree properly. With early infections, needles can be green on one side of the curved trigs and completely absent on the other side. It may take 2 or 3 consecutive years of healthy growth and nutrient transfer from roots to new needle growth to achieve the sought after appearance of uniform coloration of both new and older foliage. Therefore, a solution to the above concern is probably not more fertilization, but to improve the drainage. Soon the yellowish needles will turn brown as they die. Stressed spruces should always be fertilized for three or more continuous years either in the spring or fall. The infections are usually scattered around the lower to middle areas of the tree boughs. New Jersey Agricultural Experiment Station, Aug 2: NJ 4-H Igniting Your Leadership Potential: Growing Your Global Awareness (Day 1 of 4), Aug 1: Grape and Wine Science Certificate Program, Aug 1-3: Vegetation Identification for Wetland Delineation: South, Aug 5-13: Sussex County Farm and Horse Show/New Jersey State Fair, Commercial Blueberry Pest Control Recommendations, Commercial Cranberry Pest Control Recommendations, Commercial Grape Pest Control Recommendations, Commercial Vegetable Production Recommendations, EB-237: Pest Management Recommendations for Field Crops, Disease Control Recommendations for Ornamental Crops, Insect Control Recommendations for Shade Trees and Commercial Nursery Crops. The contrast between healthy needles and dying needles should be very obvious right now. ANSWER: This has been a common complaint with spruce trees (especially the Manitoba white spruce), but it is also common in the Colorado spruces. Further investigation is required. He can be contacted by calling 831-6503 or by email at email@example.com. The spruce tree can regrow new needles from new buds that appear in the summer, but the infected boughs will have a sparse appearance until the disease is under control. > News > Renovation & Design > TREE CARE: Yellowing spruces may have deadly fungus, By: Michael Allen Michael Allen is a consulting urban forester and certified I.S.A. Such damage typically appears as yellow speckles on the needles when viewed under magnification. Heavily infected untreated trees will eventually die. arborist and owner of Viburnum Tree Experts. 2150 Beardshear Hall Although sometimes seen on Norway Spruce, these symptoms are most common on the White & Colorado Spruce species.