![]() The symptoms may not be noticeable in the first year of infection but this disease survives on the infect needles in the winter. The infection of Needle Cast disease is favored by mild temperature and prolonged humidity in the spring. Although the damage and symptoms of Stigmina are less aggressive in comparison to Rhizosphaera, its fungal fruiting bodies can be found in both green and browning needles, making this disease easy to disperse. Then the disease continues to progress from inside out, and from older needles to younger needles. ![]() The symptoms initially show up in the inner side of the canopy as there is more humidity and shade areas. The symptoms include browning of needles, needle dropping and branch dieback. The most important disease of spruce is Needle Cast disease caused by fungal pathogens such as Rhizosphaera spp. Needle Castįigure 1 Rhizosphaera needle cast (Photo: Minnesota Department of Natural Resources, ) However, since none of the spruce trees are native to Missouri, they are suffering from both environmental stresses (heat, drought, compact soil, etc) and disease pressures from all types of plant pests. No wonder that the word "spruce" as an adjective has a meaning of "neat or smart in appearance" according to Merriam-Webster dictionary. Due to their pyramidal shape and beautiful green foliage, they have become landscape favorites over the past thirty years. Colorado blue spruce, Norway spruce and white spruce are the three major spruce trees in Missouri.
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