If many branches on the tree have needles that are turning yellow or brown and dropping, the cause may be rhizosphaera needle cast. Research Institution. The symptoms typically begin on the lower, inner portions of branches, where humidity levels normally are higher. 4). Species selection Spruce species and individual trees within each species generally have different levels of resistance to rhizosphaera needle cast. Of these, chlorothalonil was used in North Dakota experiments and proved effective. Create an Account - Increase your productivity, customize your experience, and engage in information you care about. Complete the first application just after bud break when needles are about half the size of the previous years needles. These spores are spread by splashing water and will infect all age classes of needles. The fungal spores are moved around by splashing water (either from rain drops or irrigation). Stigmina needle cast is associated with the fungus Stigmina lautii. Make sure to follow label directions if utilizing a fungicide. They may carry the fungus spores. The fungus typically will not enter the trunk of the tree and thus, it rarely will kill an entire tree but will leave it thin and unattractive. Several tools are available for the management of needle cast diseases of spruce. Disease cycle Rhizosphaera needle cast has a one-year life cycle. The first symptoms of the disease on newly infected needles will not appear until spring of the following year. Rhizosphaera cannot be reliably identified using a hand lens. However, reduced growth in the upper crown also can occur if the bottom one-third of the crown has severe needle loss, retaining less than three age classes of needles for two or more years. Needle diseases cause the most damage when the needles on the lower branches, the shady or wind-protected side and the interior crown stay wet for extended periods or when irrigation water contacts trees.

Pesticide management of needle diseases Fungicides labeled for needle diseases prevent new infections, so apply before spores and free moisture are present long enough for infection. Chemical control For landscape trees, shelterbelts and Christmas tree plantations, protect needles for two months after bud break. Generally, the tips of the branches remain green and unaffected.

Disease threshold Determine the threshold of acceptable disease when evaluating whether to implement disease management actions. 4). Both diseases have similar signs and symptoms but can cause different amounts of damage and require somewhat different management strategies, making disease diagnosis essential. Two applications would be necessary. Fungicides may be used if they are registered for the target site in the state where applied (for North Dakota, see the North Dakota Department of Agriculture pesticide database at www.kellysolutions.com/nd/pesticideindex.asp. Discolored needles typically remain attached to the tree for an additional year following discoloration. These structures are much easier to detect on green than on brown needles. More diversity will make it harder for diseases to spread..

Cytospora canker is a disease of mature spruce trees, usually older than 15 years. Probably the most common problem affecting spruce trees is a fungal disease known as Rhizosphaera Needle Cast. Photo Credit: Minnesota Department of Natural Resources Archive, Bugwood.org. Premature needle loss of spruce is the result of a variety of causes: improper planting, environmental stress, insect pests and disease. Removal of severely infected trees or branches will reduce the source of spores causing new infections. A spruce tree with dead lower branches may be suffering from a fungus disease called cytospora canker. If rhizosphaera needle cast is a concern, consider planting Norway, white or Meyer spruce. Spruce is commonly planted in urban and rural landscapes in North Dakota and frequently suffers from needle loss. Related: About a week after spring-flowering shrubs bloom, it's time to prune, Premature snipping, excessive moisture, browsing deer can endanger tulips, 'Dont be in a rush to plant everything': Chicago's volatile spring tricky for gardeners.

Because needle cast fungi are often present on larger trees even when the fungi cannot be found, to avoid severe infection pressure from Rhizosphaera needle cast, do not plant susceptible spruce trees within about 75 feet of spruce trees that are 15 or more feet tall. Royal Splendor Norway spruce appears to be immune to stigmina and rhizosphaera needle cast.

When severe, thinning of the foliage commonly occurs over the lower two-thirds of the crown of open-grown trees. Reduce stress to the tree by spreading mulch in a wide circle around the trunk to protect the roots and watering it thoroughly any time there has been no rain for a week. With experience, Stigmina can be distinguished from Rhizosphaera using a hand lens if there is good sporulation, except about the two days after a washing rain.

Multiple bands and areas of fruiting bodies may develop on a single needle.

Two major fungus diseases afflict spruces in the Chicago area, Yiesla said. These fluctuations, especially drought, stress trees and make them more vulnerable to disease. If you decide to remove an unsightly, diseased spruce, consider replacing it with a different kind of tree to reduce the risk from diseases in the future, Yiesla said. The characteristic sign of this disease is the fruiting bodies (sporodochia) that appear when mature and sporulating as small, black, fuzzy, round masses in the stomatal pores on all sides of infected needles (Fig. Rhizosphaera needle cast is caused by the fungus Rhizosphaera kalkhoffii. Disease cycle Stigmina lautii has a two-year life cycle. With the aid of a hand lens, tiny black dots can often been seen on the infected needles (these are fruiting structures of the fungus). There is no treatment for cytospora canker, according to Yiesla.

Typically, new shoots on a branch will have reduced growth if less than three age classes of green needles are present for two consecutive years. Meyer spruce can be infected, but all observed trees are relatively young and not in situations where stigmina needle cast has become severe. It usually starts on the lower branches and moves up the tree over several years, she said. The impact on growth also depends on other factors, such as nutrient availability and stress. Infections result in narrow, light yellow bands and immature fruiting bodies that are not easily visible until the following year. If you suspect your tree has this disease, contact the Morton Arboretums Plant Clinic for information on fungicide treatments or call in a certified arborist.

Cytospora Canker is another fungal disease that affects multiple spruce species, but is most common on Colorado Blue Spruce trees that are at least 10 years old. Before selecting and applying a pesticide, always read and follow the product label; it is the law.

However, white spruce appears to be highly susceptible to stigmina needle cast. Around mid-summer, infected needles begin to drop from the tree. Spraying should occur every year to ensure that three or more age classes of green needles are retained on trees (Fig. The timing of these applications is extremely important. Volatile weather is another factor. This disease rarely was recognized before 2006, but it now is known to be widespread east of the Rocky Mountains in the United States and Canada. - Increase your productivity, customize your experience, and engage in information you care about. This fungus infects individual spruce needles and can kill a tree over three or four years. 1). This is another opportunistic pathogen, meaning that it is more problematic for trees that are stressed due to drought, insects or other factors. When severe, thinning of the foliage commonly occurs on the lower one-fourth of the crown of shaded trees. Discolored needles may fall off the tree by the spring after infection or remain attached for up to two years. The cankers often will be covered with a white or bluish white resin, a characteristic symptom of Cytospora Canker. Trees are most likely to be infected if they are planted too closely together or if they are stressed, Yiesla said. Timing of the second application depends on which fungicide is used. A sunken canker forms on an infected branch and eventually will girdle and kill that branch, which causes the needles to turn brown and drop off. Use equipment that is large enough to get fungicide onto the lower two-thirds of treated trees. Signs and symptoms of the disease The first symptom that appears is a faint yellow band on a needle. Protect the new needles for two to three years to allow infected needles to be shed and decompose.

The threshold differs depending on the expected tree function. Carefully inspect any new spruce trees that will be planted to ensure they are free of signs and symptoms of the disease. See www.ag.ndsu.edu/pdl for instructions on how to submit a sample and a mailing or shipping address. Norway spruce, blue spruce and white spruce are among the most popular trees in the area, prized for their winter color and ability to screen out the neighbors.

Land Grant. Both pathogens may be present at the same location and even on the same needle. Another common symptom is white sap on the trunk or branches.

Using them in the appropriate situations and combinations is the best way to reduce the impact of these diseases. Symptoms of Rhizosphaera Needle Cast typically start to appear in late winter or early spring with needles turning brown or purplish brown. Be sure to disinfect your pruners with rubbing alcohol or another disinfectant between pruning cuts. In most Chicago suburbs, you cant drive a block without seeing a spruce tree. The characteristic sign of this disease is rows of small dark brown or black smooth spherical fruiting bodies (pycnidia) that emerge through the stomatal pores on all sides of infected needles (Fig. Spores typically develop in the spring when high temperatures are consistently above 40 F for a few days and have been observed to develop as early as mid-March. For tree and plant advice, contact the Arboretums Plant Clinic (630-719-2424 or plantclinic@mortonarb.org). In North Dakota, pycnidia produce spores in late May through July. A fungicide could also be applied in the spring to protect needles.

Needle loss caused by these diseases is usually restricted to the lower crown. 2). Protect new needles from new infections for a minimum of two months early in the growing season for two to three years. Cultural control The cultural control methods described above for rhizosphaera needle cast may reduce stigmina needle cast but are not adequately effective without concurrent chemical control. Over the last few years, weve had a wide range of weather, including dry spells, wet periods with flooding, and really bitter winter days, she said. To avoid severe infection pressure on young trees, do not plant susceptible spruce trees within about 125 feet of spruce trees that are 15 or more feet tall. Original Authors:James Walla, Plant Pathologist, NDSU Department of Plant Pathology, RetiredJared M. LeBoldus, Plant Pathologist, NDSU Department of Plant PathologyAaron Bergdahl, Forest Health Specialist, North Dakota Forest Service. If conditions favor disease development, the symptoms typically progress from the areas that are the most favorable to those that are less favorable during the course of several years (Fig. Carefully follow all label directions. [Related: About a week after spring-flowering shrubs bloom, it's time to prune], [Premature snipping, excessive moisture, browsing deer can endanger tulips], ['Dont be in a rush to plant everything': Chicago's volatile spring tricky for gardeners]. Colorado blue spruce are the most susceptible, white spruce are intermediate and Norway spruce are resistant. Everybodys got a spruce, she said, and every one of them is a potential host plant.. These spruce diseases are an example of the price we pay for planting too many of the same trees, she said. These spores can infect any age class of needle throughout the growing season whenever temperatures are above about 50 F with free moisture. Trees that are stressed from drought, insects or other factors are more susceptible to Rhizosphaera Needle Cast. There are a couple relatively common fungal diseases that affect spruce trees, especially Colorado Blue Spruce, which, when planted here is outside of its native range. This disease can affect most species of spruce, but is especially problematic on Colorado Blue Spruce. On severely infected needles, the pycnidia may appear to the naked eye as continuous fine black lines up and down the length of the needle. Meyer spruce appears to be relatively resistant to rhizosphaera needle cast, but more research is needed. Most Colorado blue spruce and white spruce are highly susceptible. The band expands and, in as little as two months, changes from yellow to brown to reddish brown or purple. Pycnidia often appear by late May, and spores are produced soon after. Student Focused. When entire lower branches on a spruce have died, the problem is more likely to be cytospora canker, Yiesla said. Signs and symptoms of the disease Symptom development is similar to that of rhizosphaera needle cast.

In North Dakota, sporulation can occur when the temperature is above about 40 F for a few days. Interplanting different tree species among spruce trees also will help limit the tree-to-tree spread of this disease. Unfortunately, their popularity is one reason spruces are increasingly vulnerable to fungus diseases, according to Sharon Yiesla, plant knowledge specialist at The Morton Arboretum in Lisle.

Management options that can be implemented include cultural practices such as watering during periods of drought (do not let the water splash down on the needles), mulching around the base of the tree (dont pile mulch against the trunk of the tree) and planting either Norway or White Spruce, both of which are less susceptible than Colorado Blue Spruce. 3), giving trees a sparse and hollow appearance. Needle loss that causes growth reduction for two to three years threatens the long-term health of a tree. Feel free to use and share this content, but please do so under the conditions of our, The Old and the New: Two Needle Diseases of Spruce in North Dakota, James Walla, Plant Pathologist, NDSU Department of Plant Pathology, Retired, Jared M. LeBoldus, Plant Pathologist, NDSU Department of Plant Pathology, Aaron Bergdahl, Forest Health Specialist, North Dakota Forest Service. Beth Botts is a staff writer at the Morton Arboretum in Lisle (www.mortonarb.org). For nurseries, where certification requires that plants be disease-free, needles should be protected for the entire infection period (about six months in North Dakota, from mid-May to mid-October) until infected needles are no longer found, likely after four or five years. For a small fee, samples can be submitted to the NDSU Plant Diagnostic Lab for disease identification. Needles that remain attached to the tree and those that recently fell to the ground may continue to produce spores. Finally, maintain vigor by including supplemental fertilization if needed, avoiding sites or conditions too wet or dry for spruce, avoiding damaging herbicide application near the tree, reducing root competition with other plants and avoiding mechanical damage to tree roots.

Confirmation of pathogen identity usually requires microscopic observations and measurement of the spores. This fungus lives under the bark and destroys the vessels that carry water and nutrients, so the whole branch dries out and dies. Infected branches can also be pruned and destroyed during dry weather. Chemical control Fungicide applications at appropriate times are a management tool for rhizosphaera needle cast. (The Morton Arboretum).

A spruce tree with dead lower branches may be suffering from a fungus disease called cytospora canker. Rhizosphaera needle cast and stigmina needle cast infect Colorado blue spruce (Picea pungens), white spruce (Black Hills) (Picea glauca), Norway spruce (Picea abies) and Meyer spruce (Picea meyeri).

On most trees, sporodochia develop by late spring the year after infection, mature that fall and produce spores under conditions that allow infections the next spring. A tree can live with the disease for a few years its not an immediate death sentence, she said but branches will continue to die. Sporodochia are very small and not sporulating from late fall to early spring in North Dakota, making microscopic identification difficult during this period without incubation and detailed spore observations. Species selection Planting tree species other than spruce should be considered in areas where stigmina needle cast is causing substantial damage (all of eastern and some of central North Dakota), particularly if the disease is present in the same planting. Pycnidia are observed easily with a hand lens when mature. Symptoms are somewhat similar to Rhizosphaera Needle Cast, typically beginning in the lower branches of a tree. The spores of this fungus can be transported by wind or splashing water (both rain and irrigation). The bands or entire needles may change color, becoming darker yellow, purple, tan, reddish brown or brown. While this fungus will not usually kill a tree, severe infestations can leave a tree thin and unattractive. A specimen tree may be expected to maintain a full complement of green needles, while trees in a windbreak may achieve their function with substantial needle loss and some branch death. Management options that can be implemented include cultural practices such as watering during periods of drought (do not let the water splash down on the needles), mulching around the base of the tree (dont pile mulch against the trunk of the tree) and providing ample space between trees to ensure good airflow. Remove every dead branch with a clean pruning cut next to the trunk, she said. This historically has been the most common spruce disease in North Dakota. Cultural control Ensure adequate spacing between trees, maintain new spruce trees in sunny locations so needles dry quickly, facilitate air movement to promote needle drying by pruning lower branches of spruce trees and ensure that irrigation water does not wet trees in the early morning or late evening. The susceptibility of Norway and Meyer spruce is unclear, although there have been reports of these species infected by Stigmina lautii. Chemical controls only are effective if the disease is caught early, and they must be applied at a specific time of year, Yiesla said. This may result in only the current-year needles remaining green (Fig.

Follow label directions for optimum coverage. Be diligent about removing all fallen branches and needles from beneath the tree.