This is what she shared: Al: How can landowners identify Rhizosphaera needle cast? Use the mature size of the tree as a spacing guide when planting. All other rights reserved. Begintreatment with a registered fungicide in spring at half-needle elongation. Daconil Weatherstik is not labeled for blue spruce in the landscape but is still available for use in the nursery and for other landscape diseases. Its cells are live cells that conduct water movement, In 1929 the Northeast Illinois Council of the Boy Scouts of America purchased an old logging camp near Pearson, WI, located about 25 miles northeast, Q: Ive always thought leaving a forest undisturbed was the best strategy for attracting wildlife. by contacting your local certified arborist. Cold Pressed Neem Oil Seed Extract (Makes 24 Gal. Feedback, questions or accessibility issues: Growing and Caring for Plants in Wisconsin: Foundations in Gardening, https://learningstore.extension.wisc.edu/, Smart Shopping: Dodging Disease When Purchasing Plants, Tips for Buying and Caring for Easter Lilies, Avoiding WinterSaltInjury on your Landscape Plants, 2022 The Board of Regents of the University of Wisconsin System. Senator Baldwin was joined by Kretz Lumber leadership and, While weve been producing and delivering high quality lumber for more than 90 years, we might be new to you. To confirm, fungal structures may be seen on affected needles with a hand lens as rows of black specks. Please contact site owner for help. When attempting to determine the cause of needle drop, examine the branch carefully to determine if the problem is normal needle drop, the yearly occurance on normal needle shedding. Rhizosphaera needle cast may be controlled in one year if fungicides are applied correctly. Inspect the depth of the mulch layer each year. Box 30001 | Las Cruces, NM 88003-8001, 2022 New Mexico State University - Board of Regents. It makes Colorado blue spruce unsightly and unusable in many landscape settings. The University of Minnesota is an equal opportunity educator and employer. Needle discoloration: yellow to reddish-purple to brown, Symptoms develop first on the oldest needles on branches in the lower plant canopy, Black pycnidia (fruiting bodies) develop on infected needles, Warm temperatures (6575F), wet weather, Avoid planting new trees next to established trees, Promote good air circulation around trees by open spacing, selective pruning, and removing brush and grass around trees. Fungicides must be applied during the spring infection period to work. The easiest way to avoid Rhizosphaera needle cast is to avoid planting Colorado blue spruce. In spring or early summer, new needles at the branch tips are green, and the older needles turn brown to purple. But, some blue spruce will be much more susceptible to this needle disease throughout their lives, regardless of the weather, and may need continued treatment to maintain a full complement of foliage. Please be aware that pesticide labels and registration can change at any time; by law, it is the applicators responsibility to use pesticides ONLY according to the directions on the current label. Last Revised: 03/03/2021 This disease causes needles on Colorado Blue Spruce to turn a purplish brown color before dropping from the branches prematurely. It turns out that several issues are known to affect Colorado blue spruce (Picea pungens). Blue spruce tree infected with Rhizosphaera needle cast exhibiting defoliation and branch dieback, (photo by NMSU Bernalillo County Extension), College of Agricultural, Consumer, and Environmental Sciences, https://pubs.nmsu.edu/_circulars/circ554/, Rhizosphaera Needle Cast Disease of Blue Spruce. Label directions for using pesticides should be followed precisely. Premature needle drop is the primary damage, causing the tree to become unsightly. Twelve to fifteenmonths after infection, needles will drop prematurely. For permission to use publications for other purposes, contact firstname.lastname@example.org or the authors listed on the publication. Products shown as available are normally stocked but inventory levels cannot be guaranteed, For screen reader problems with this website, please call 1-800-430-3376 or text 38698 (standard carrier rates apply to texts). Johnson. Pruning the lower branches off will allow better air flow under the tree and dry off the needles more quickly after rain or dew events. Fig. Older needles will become infected and turn rusty brown color and drop off prematurely. Figure 3. There are two blights common on pines, mainly Austrian and ponderosa. ). If left uncontrolled, the disease can eventually kill the tree. If you have questions related to the spruce on your property, contact our Forestry Services team by email or call us at 800-352-1438. Dry needles are less likely to be infected. Pycnidia (black fruiting bodies) of Rhizosphaera kalkhoffii on an infected blue spruce needle (photo by Paul Bachi, University of Kentucky Research and Education Center, Bugwood.org). Its a mouthful, no doubt, and its wreaking havoc on our spruce population. Last year (2017) was a very wet year all throughout the growing season, so the problems were seeing are directly tied to the weather last year. Use pesticides selectively and carefully and follow recommended procedures for the safe storage and disposal of surplus pesticides and containers. To control, make the first fungicide application in mid-May to protect existing needles and a second application about mid-June to protect new growth. Treatment for four to five consecutive years may be needed. Blue spruces native range spans from northern New Mexico through Colorado, and Utah to Wyoming, and into Alberta and British Columbiaareas with a much cooler and drier climate. However, it has been widely planted as an ornamental tree far beyond that range. 1987. As the disease continues, trees become unsightly and lose their value as a visual screen or privacy fence. Destructive epidemics of needle casts or rusts are not uncommon, and develop under periods of extended leaf wetness.
All rights reserved. Discolored needles fall off in late summer to fall. The leaf of Virginia Creeper looks similar to the leaf of the Buckeye tree. 3. Blue spruce trees are much more susceptible to the disease than white spruce, but were seeing heavily impacted white spruce this year too. Often, the youngest needles at the tips of branches remain healthy. Use a magnifying glass to look closely at both green and discolored needles. When planting new trees, consider planting Norway or white spruce, which are more resistant to Rhizosphaera. Norway spruce (P. abies) is relatively resistant but can become infected when grown under stressful conditions. This greatly reduces the vigor and aesthetic quality of affected trees. Proper timing and thorough coverage of the entire tree will be critical to successful control. Do not overcrowd plants. The after-affect of these epidemics can persist for several years. Ft. Collins, CO: U.S. Department of Agriculture Forest Service, Rocky Mountain Forest and Range Station. The best course of action is to pull these vines by hand from the soil in the spring, before they start the trek up your pine trees. 1983. 1986. Trees stressed from drought, poor planting practices or other factors are more likely to suffer from Rhizosphaera needle cast. Figure 4. H-158: How to Collect and Send Specimens for Disease Diagnosis https://pubs.nmsu.edu/_h/H158/, H-160: Mimosa Vascular Wilt https://pubs.nmsu.edu/_h/H160/, CR-554: Verticillium Wilt of Catalpa, Maple, and Elm https://pubs.nmsu.edu/_circulars/circ554/. Infected trees have few needles near the trunk and look thin, or see-through. The length of time that a needle is retained depends on the species of coniferous plant and if the plant has been subjected to stress such as drought, flooding, salt damage, disease, or insect pest. Spruce trees grow best in moderately moist, well-drained soils but can be planted in other soils if adequate moisture is available. Please call us at: 1-800-HOME-DEPOT (1-800-466-3337), Please enter in your email address in the following format: email@example.com.
Spruce ideally hold its needles for several years, but older needles infected by rhizosphaera drop off years before they normally would. Also, another prevention strategy for landowners to use is to prune the lower branches of their spruce. Kretz Lumber Co., Inc. All rights reserved. Spam protection has stopped this request. OnColorado blue spruce, infected needles often show symptoms ofyellow mottling in mid-to-late summer. ), 64 oz. 3), which is the best time to control this disease. Fungicides labeled for spruce are effective if damage is not already too severe. This Home Depot guide illustrates detailed description of proper applications of lime and gypsum fertilizers, including information on seasons, quantity and frequency. Linda: Rhizosphaera needle cast is a fungal needle disease that causes needles to die and drop off the tree prematurely. Avoid heavy clay, as trees planted on these sites often suffer iron, magnesium, and manganese deficiency. Even though fungicide application will effectively control this disease, reinfection may occur in subsequent years. Peterson. Ask a Forester: Is leaving a forest undisturbed the best strategy for attracting wildlife? Other hosts include: deodar cedar,Douglas fir, true firs, hemlocks, pines and coast redwood. Norway spruce is more resistant but were even seeing some of those trees being impacted. Branchesthat lose first-year needles for 3 to 4 consecutive years may die. If trees are infected, fallen needles should be cleaned up and put in a sealed plastic trash bag and sent to the dump. Infected needles turn brown from the tip back to the lesion. Needle casts vary by host, and severity is dependent upon the age of infected needles. What does Rhizosphaera needle cast look like? When setting out sprinklers, direct the water away from needles. X-number: XHT1006. Depending upon how long the lower branches of your tree have been affected, an application of a fungicide containing chlorothalonil applied 2 or 3 times per season for 2 to 3 years might be effective in controlling the disease and allow for growth of new needles on the lower branches in future years. The best control measures are to plant only healthy trees and avoid planting new trees next to established trees. Other spruce, like Serbian, simply havent had widespread evaluation in the Midwest, so buyer beware! New growth may appear at the ends of some of the bare branches in the spring, so you may think the tree is recovering, but this new growth is often infected during the growing season. Yearly fungicide treatments can help with needlecast but appropriate timing and good coverage are essential to reduce needle loss. Spectro-90, or copper-based fungicide, can protect new growth and prevent new infections; Concert II, Heritage, Pageant, and Trinity are labeled for use in commercial and residential landscapes, and nurseries, but data regarding their efficacy is lacking for this disease. ), 8 oz. As a result some chlorothalonil-based fungicides are listed as phytotoxic to spruce trees.
Infected trees can be sprayed with Bordeaux mixture 8-8-100 (8 lb hydrated lime, 8 lb copper sulfate, 100 gal water) or fungicides containing chlorothalonil or thiophanate methyl. Lab analysis is necessary to distinguish Rhizosphaera needle cast from other diseases of spruce trees. The disease is spread primarily by rain water splashing the spores from infected needles to newly emerging needles in the spring. Editors note: Throughout the growing season, Mike Hogan, OSU Extension Educator for Agriculture & Natural Resources in Franklin County, will answer gardening questions submitted by Dispatch readers. Apply treatments every three to four weeks starting as new needles emerge in the spring. The disease usually attacks the oldest needles on branches in the lower portion of the tree canopy first and progresses upward, giving the appearance of death from the bottom up and inside out. Older needles can become infected if environmental conditions are highly favorable for disease. Theres a blue spruce tree right outside my bedroom window. Al: Why does this seem to be such a problem this year? Annual Tree and Shrub Insect Control Concentrate, 32 oz. Most conifers retain their needles for two to seven years. Send your questions to [emailprotected]. How can we control this fast-growing vine? Branches that defoliate for four or five years may die. Damage typically starts on the lower branches and moves up the tree. However, infected needles often dont show symptoms right away, and may take one to three years to develop. A second treatment should be applied 3 weeks after the initial treatment. For more information on Rhizosphaera needle cast: See UW-Extension Bulletin A2640, Colorado Blue Spruce and Other Conifers Disorder: Rhizosphaera Needle Cast (available at https://learningstore.extension.wisc.edu/) or contact your county Extension agent. Application to large trees requires special equipment to ensure adequate coverage. These black spheres are fruiting bodies (i.e., reproductive structures) of the fungus that causes the disease and are diagnostic. Needle infection occurs best during warm (77 F) wet weather. In spring through early autumn, spores spread to new needles within the tree or in neighboring trees via splashing water. Make a second application 3 to 4 weeks later. Properly prune dead or severely infected branches during dry weather. Leave at least a 2 inch space between the mulch and the trunk to allow for air movement. Properly spacing spruce trees will help reduce disease incidence. Extension Plant Pathologist/Distinguished Achievement Professor, Department of Extension Plant Sciences, New Mexico State University. Sinclair, W.A., H.H. The disease is problematic in landscape settings, particularly when trees are planted too close together. ), Natria Ready-to-Spray Insect Disease and Mite Control, 24 oz. The disease usually starts near the base of the tree where humidity levels are the highest, but continues to spread upward. What is the cause of this and what can be done to save these trees? Tiny black bumps can be seen arranged in neat rows on infected needles. 1. The disease affects trees of all ages. Trees planted close together in groups or close together in a tree line tend to especially be affected by this disease.