News » 20.05.2025 - Protecting flowers from Botrytis in mixed containers and cell-pack flats

The fungal pathogen, Botrytis cinerea, produces spores profusely on senescing and injured tissues under moist, humid, low light conditions. This can lead to explosive epidemics of the pathogen, as well as loss in sales of large mixed containers due to individual plant death. Smaller, shaded plants (often where watering was inconsistent) can be infected and eventually killed by Botrytis. With close container spacing and hanging baskets produced over bench crops, senescing flowers from hanging baskets can land on leaves on the crop below and provide an entry point for Botrytis infection.

Botrytis symptoms include blighting of tissues often at the soil line that moves upward in the plant causing tan lesions and leaf/plant death. Often "fuzzy", gray- to white-colored sporulation is visible on the killed tissues. Within finished cell-pack flats and larger containers planted with multiple plants and plant species, Botrytis can start in one plant and then quickly move into adjacent plants causing leaf death and a shortening of flower life. With mixed containers, it is unusual for the whole container to be affected; however, infection of a few plants can lead to holes in the plant coverage, shortening of flower life, and container culling or a reduction of sale price.

Scout for Botrytis and remove infected tissues and plants to reduce disease spread. Water management is also important for Botrytis infection and control. It only takes 4-8 hours of plant wetness for Botrytis spores to germinate and infect. High humidity (above 85%) allows Botrytis to produce an abundant number of spores. Management of Botrytis is multi-pronged. Plant wetness should be minimized by avoiding wetting the foliage as much as possible.
 

Source: www.floraldaily.com

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