When we reflect from year to year on common challenges growers face, we keep going back to two stakeholders in the greenhouse: gerbera daisies and begonias. These two staples for spring sales share basic cultural requirements, but are unfortunately also plagued by similar diseases. The objective of this article is to highlight diseases associated with gerbera and begonia and provide effective cultural strategies for preventing them.
Foliar and Stem Diseases
Starting with the biggest selling point for both crops, the flowers, we see the omnipresent Botrytis rearing its head here every season without disappointment. Being already incredibly sensitive to overheard irrigation, and with only a few hours of free moisture needed for development, Botrytis can rot tender begonia blooms quickly. Botrytis and its close friend Rhizoctonia can also be associated with causing stem cankers on the flower stalks of gerberas or within the canopy of a pot-to-pot begonia crop. This can cause entire stems to collapse, with a visual appearance of drought stress and/or a nutrient deficiency. Growers should consider watering when environmental conditions allow for quick drying (i.e., moderate to high light intensity and low relative humidity) and always maintain adequate airflow across the crop canopy.
Photo: Botrytis spreading within the begonia canopy attacking senesced blooms, foliage, and stems. Credit: Griffin