ChileanJAR

Necrotic leaves, defoliation and dieback of shoots in blueberry were associated with high levels of urea and ammonium fertilisers, when 2 year old blueberry plants, maintained in pots, were fertilised with 1 to 36 g/plant of N. Foliar manganese concentration showed a positive and significant correlation with the amount of fertiliser applied, increasing to excess levels as the fertiliser rates increased over 4.2 g/plant of N. Botrytis cinerea and Pseudomonas syringae, pathogens commonly associated to the above symptoms, were not isolated from affectedplants. Symptoms caused by these pathogens, when plants were artificially inoculated, developed slowly and were different from those caused by high levels of fertiliser.