The Effect of Fertilisation on the Severity of Sirococcus Shoot Blight in a Mature Norway Spruce (Picea abies [L.] Karst.) Stand

Abstract

The paper reports on the effect of fertilisation on the severity of Sirococcus shoot blight in a mature Norway spruce stand. Trees with severe symptoms of Sirococcus shoot blight were characterised by insufficient Mg and Ca supply and enhanced N/Mg and N/Ca-ratios in the currentyear and 3-year-old needles at the start of the project. Application of appropriate fertilisers in 2001 mitigated disease severity of the fertilised trees and promoted tree recovery. Best results were achieved by fertilisation with a water soluble Ca- and Mg-fertiliser (gypsum + kieserite-variant) which resulted in an 18.9 % decrease of disease severity in the period 2001 – 2006. While dolomitic liming also promoted tree recovery (decrease in disease severity was 11.8 %), in the unfertilised control variant a 3.5 % increase was observed in the same period.