Damage done by Botrytis tulipae developed in a variety of ways after planting naturally and artificially inoculated bulbs, the fungus sometimes rapidly invading developing shoots, preventing their emergence. In other instances (a) leaves emerged above ground, but not before being severely infected (the traditional 'primaries'), (b) leaves emerged uninfected but the flower stalks were attacked at a later stage causing mechanical weakness (and hence frequent snapping), or (c) leaves and flower stalks remained uninfected, with the development of B. tulipae being restricted to its spread from mother to daughter bulbs, which also occurred in (a) and (b). More emerging shoots were infected when inoculated bulbs were grown at 10 degrees and 15.5 degrees than at 4 degrees C-an effect suggesting that greater numbers of foliar primaries would develop in mild winters. The underground transmission of B. tulipae indicates the need for eradicating infections in the bulb, the primary sources of this pathogen.
