Cronartium flaccidum on Pinus spp.: relation of inoculum concentration to symptom development

An experiment on the effect of eight inoculum concentrations of basidiospores of Cronartium flaccidum, on development of symptoms on P. nigra spp. nigricans var. austriaca, P. nigra ssp. italica, P. nigra ssp. laricio var. calabrica (from Calabria and Corsica) showed that 60000 basidiospores/ml was the optimum concentration and P. nigra ssp. laricio was the most sensitive.