Dieback of florist's geranium caused by Botrytis cinerea . Losses are particularly high in vegetatively propagated P . Stock plants are grown close together and have multiple branches and a dense canopy that is created with growth regulators in order to maximize cutting productivity. Consequently, lower leaves of stock plants typically senesce and become colonized by B. cinerea , resulting in a massive buildup of inoculum. B. cinerea infections may also develop at the cutting bases or at leaf scars during propagation under mist.
Flower blight is common.
Geraniums sometimes show ghost spots indicative of Botrytis lesions whose development has been arrested. Causal Organism Fig. Botrytis cinerea sporulation. Conidia are budded off from a swollen, sporogenous cell at the tip of the conidiophore. Whetzel, which is only rarely observed forming apothecia on sclerotia.