Excesses of soluble nitrogen source will promote thin walled cells, encourage “thatch” and lead to increased Fusarium Patch disease. Excesses of nitrogen applied in autumn should be avoided as this will lead to lush growth which is easily damaged. Such damage then provides infection points for the disease to spread rapidly.
Even some organic nitrogen sources such as Dried Blood are surprisingly quick acting and can lead to outbreaks of Fusarium when applied late in the year. It is not only excesses of nitrogen that can promote Fusarium Patch, weak thin swards which suffer from deficiencies in Nitrogen are also more prone to disease. Where disease is a concern and “Black Layer” is not a problem use acidifying fertilisers containing sulphate e.g. Ammonium Sulphate as this will lower pH and discourage Fusarium Patch.