Sporulation of Botrytis cinerea in the dark

Abstract Forty‐three isolates of Botrytis cinerea Pers.: Fr., selected for their moderate — high degree of sporulation in light, were tested for their ability to sporulate in complete darkness. Twelve showed no sporulation in darkness whereas 31 showed varying degrees of sporulation. Eight of these sporulated as well in the dark as in the light. When tested on bean leaves for their ability to invade and grow in tissue after wounding, isolates that could sporulate in the dark showed no difference from those that could sporulate in the light. Because these strains capable of sporulation in the dark are fairly common, the use of near‐UV film as a greenhouse covering may not be an effective control measure against this pathogen.