The cause of smoulder and the infection of narcissus by species of Botrytis.

Cultures of Botrytis isolated from narcissus were readily identified from their sclerotial characteristics on potato dextrose agar. B. narcissicola was isolated most frequently from typical smoulder symptoms. Infection of narcissus by isolates of B. narcissicola and B. cinerea was investigated using conidial and mycelial inocula on detached leaves and bulb scales. Only mycelial inocula of B. narcissicola isolates consistently caused spreading lesions. Conidial inocula of both species typically failed to colonise healthy narcissus tissue when inoculated in sterile distilled water but B. narcissicola caused some spreading lesions after tissue damage, in senescent tissue, or following the addition of certain nutrients (including pollen) to inoculum droplets. Cultivars differed in the resistance of their bulb scales. The specificity of Botrytis-narcissus interactions is discussed. [ABSTRACT FROM AUTHOR]