Tolerance to SNC, not resistance, seems to be the important factor in genetic variation in SNC symptoms following infection by P. gaeumannii (Temel et al. Don’t plant trees to close together. Genetic selection for SNC tolerance at the seedling stage has been shown to be successful for increasing tolerance in older trees (Temel 2005). Northwest Tree Improvement Cooperative Website, College of Forestry, Oregon State University, Quantification, Assessment, and Severity Prediction, Tree Genetics, Resistance, and Improvement, Integrated Pest Management & Silviculture. Follow proper irrigation practices; keep water off the foliage. Rhizosphaera needle cast disease is caused by the fungus Rhizosphaera kalkhoffii Bubak. Early testing of seedlings can eliminate poorly performing families at seedling stage before further testing, and allow for rapid screening of large numbers of already selected families so that the most SNC tolerant individuals can be used for seed orchards (Temel 2005). Growth of the fungal pathogen from the spots on the needle will cause the death of the entire needle. Trees planted on poor sites are more likely to be infected with Rhizosphaera needle cast due to stressful conditions. Major research findings involving Swiss needle cast and its causal agent: All cited publications are available on this website. 2005; Fig. Instead, consider planting Norway spruce, which is resistant. Of the foliage traits, crown density is seen as a better indicator of SNC tolerance than needle retention (Johnson 2002). Although the needles become infected symptoms of disease often are not visible until the following winter or spring season. Minimize stress to the trees by water during periods of drought. A spruce exhibiting discoloration and loss of foliage as a result of needlecast. I live in Washtenaw county and many of my neighbors evergreen trees are dying from needle cast diseases. I would like to know what would be a good evergreen to plant to help screen my home from my neighbors. White spruce and other conifers, like pine and fir, are also susceptible. Foliage traits (needle retention, crown density and color) are reasonable indicators of SNC tolerance, but appear to be under less genetic control to a lesser degree than growth rates (height, volume, DBH, and DBH increment). This will minimize moisture retention on the foliage and will decrease the likelihood of disease development. However, little differences in susceptibility were observed between Douglas-fir seedlings from different locations in the Oregon Coast Range. Young trees sustain the most severe damage, but trees of any size can be affected. The likelihood of having success with any tree can be improved by choosing trees that are correct for you site. Selection of Douglas-fir genotypes with shorter needle longevity could increase forest productivity by removing infected needles sooner, thus limiting the net drain on carbon assimilation and growth (Manter et al. The first step is to get a reliable diagnosis. The symptoms of needle cast first appear on needles as light green to yellow spots, which eventually turn red or brown. Needle cast is a broad group of fungal diseases that cause conifers to shed needles. Field identification is based on symptoms, but accurate identification requires laboratory analysis.Healthy spruce trees will retain 5 or more years of needles. This shedding of needles can be more serious to conifers than losing leaves is to deciduous Rhizosphaera needle cast is caused by fungal pathogens within the genus Rhizosphaera.This genus also infects several conifer species including; fir, cedar, spruce, and pine 2003). and if you had a soil test to look at the pH we can make better recommendations. Avoid planting highly susceptible species in low or shady areas where humidity and moisture remain high for prolonged periods. Plant Norway (P. abies) or white spruce (P. glauca) as they are more resistant to Rhizosphaera needle cast. Follow proper planting practices. When planting new trees in the landscape, space them to allow for optimum air circulation and sunlight penetration into the trees interior. Evergreen tree resistant from needlecast disease . If you have seen trees affected by needle cast disease in the area, avoid planting this highly susceptible tree. Plant spruce trees on sites with acidic, moist, well drained soils and full sun. Colorado and Engelmann spruce are very susceptible, but Norway and white spruce are somewhat resistant. Ask an Expert is made up of groups and individual experts. Unfortunately, there are a number of pests (disease and insects) that affect trees. Since growth-increment data are not always readily available for use in breeding programs, foliage traits can be a valuable tool, particularly for early-selections. Asked October 3, 2019, 10:53 AM EDT. If you can tell me more about your site (soil, drainage, etc.) Tolerance refers to a trees ability to grow well in the presence of disease, while resistance refers to the trees ability to avoid or prevent infection. Rhizosphaera needle cast is the most common disease on spruce trees that is received in the Plant and Insect Diagnostic Clinic. Key site factors for conifers are full sunlight, good air movement and excellent soil drainage. 2004; Temel et al. I am looking for advice on something that can grow to be 18-20 feet or taller and is evergreen year round for screening purposes, but is also hardy against the current needlecast problems in the area. Thank you for your help. Infected needles may then turn yellow or brown with characteristic dark fungal fruiting structures. Gaining tree genetic information in relation to Swiss needle cast (SNC) is an important component of programs designed to develop Douglas-fir seed sources with genetic tolerant to SNC. https://www.canr.msu.edu/news/alternative_conifers_for_michigan_landscapes. While visually unappealing, these diseases rarely lead to tree mortality on their own. I would like to know what would be a good evergreen to plant to help screen my home from my neighbors. We were planning to plant some Norway spruce trees to help screen our house from the … I live in Washtenaw county and many of my neighbors evergreen trees are dying from needle cast diseases. (2002) found needle retention a good predictor for growth loss at the stand level, and crown density may be the single best predictor (Johnson 2002). However, infected needles often don’t show symptoms right away, and may take one to three years to develop. if there is evidence of variation in economically important traits (i.e. Here is a link to a publication to look at some options. Control weeds and other vegetation from encroaching around the base of trees to encourage air circulation among and light penetration to the lower branches. 1). Gaining tree genetic information in relation to Swiss needle cast (SNC) is an important component of programs designed to develop Douglas-fir seed sources with genetic tolerant to SNC. The primary goals of tree improvement are to determine: 1.) if economically important traits are linked or can be inherited together, and 3) the degree of genetic control over the desired traits. A broad range of fungal diseases that cause foliar discoloration and needle loss in conifers are known as needlecasts and needle blights. Plan for the mature size of the tree(s) when spacing plants, or plan to remove trees as they begin to intermingle lower branches. Rhizosphaera needle cast is a fungal disease, caused by Rhizosphaera kalkhoffii that attacks the needles of Colorado blue spruce in the spring, as new needles emerge. volume growth or disease tolerance) between families, 2.) Maguire et al. We were planning to plant some Norway spruce trees to help screen our house from the neighbors, but it appears that Norway spruce can also get needle cast problems. This is, in part, because all Douglas-fir trees are susceptible to infection by P. gaeumannii, but there is some evidence that Douglas-fir sourced from dry, inland areas experience relatively more fungal colonization than Douglas-fir from wetter, coastal locations. https://www.canr.msu.edu/news/alternative_conifers_for_michigan_landscapes. Needle cast diseases are caused by various fungi that infect the new needles on pines, spruce, Douglas fir, and true fir.