Trees that are stressed from drought, poor Stigmina is the fungus most commonly encountered in association with diseased spruce samples submitted to the Manitoba Crop Diagnostic Centre but both diseases are known to occur here. NEEDLE CAST DISEASES OF SPRUCE Two needle cast diseases caused by fungi Rhizosphaera kalkhoffii and Stigmina lautii, respectively, are commonly found on spruce … Other fungi, such as Stigmina sp., have been implicated in spruce defoliation in a similar pattern Plant Pathology Fact Sheet Common Diseases of Spruce in Kentucky F igure 1. Infection, which begins in spring, usually appears first scattered among the lower branches and may cause severe loss of needles. Blue spruce varieties are very susceptible to Rhizosphaera. Send a sample for diagnosis now Treatment for Rhizosphaera Needle Cast or Stigmina Needle Cast , two common diseases of spruce trees in Minnesota, need to begin at this time of year. There is no chemical labeled for treatment of stigmina at this time. Spruce spider mites This mite primarily feeds on older, inner needles, causing needles to look pale, yellow and sickly. However, there is another needle cast fungus, Stigmina lautii that is infesting more species of spruce including white spruce. Needles affected by Rhizosphaera needle cast Rhizosphaera and stigmina needlecast of spruce Both of these fungal diseases cause purpling, then death and dropping of second year and older spruce needles. Spruce trees often thrive in North Dakota under the right conditions. Stigmina affects all spruce. The first step in correcting a spruce problem is getting a correct diagnosis.