Reply: Apply Dolomite two clenched handfuls per sq metre and a dressing of Blood/Bone. Only use decomposed cow manure as fresh it destroys the texture of your soil and prevents the soil from breathing. Iwould also apply Epsom salts to the soil(Magnesium Sulphate) as your Lemon has the symptoms. Control scale by spraying with PEST OIL EVERY TEN DAYS UNTIL CONTROLLED.