First report of web blight on rose campion (Lychnis coronaria) caused by Rhizoctonia solani AG 1-IB in Italy.
In the summer of 2014, a web blight was observed in a private garden located near Biella (northern Italy) on 40% of 100 5-month-old plants of Lychnis coronaria (syn. Silene coronaria), grown on sandy soil. In the days preceding the outbreak of the disease, daytime temperatures ranged from 18 to 24°C and relative humidity from 45 to 83%. Affected plants showed pale brown discoloration of stems, starting from the base, and eventually collapsed. Under conditions of high relative humidity, a scant amount of whitish mycelium developed on leaves of ∼50% of diseased plants. Eventually, infected plants died ∼10 days after symptoms appeared. Based on morphological characteristics, sequence analysis of the rDNA internal transcribed spacer region and pathogenicity tests, the causal agent was identified as R. solani. This is thought to be the first report of blight of L. coronaria caused by R. solani in Italy or anywhere else in the world.