Florida’s winters are typically dry, but the wet winter of 2015-2016 helped spread pathogens that destroyed many ornamental plants in Miami-Dade County, according to University of Florida Institute of Food and Agricultural Sciences (UF/IFAS) researchers.
Damage figures are not yet available from the 2015-2016 winter rains, but UF/IFAS scientists found that pathogens Phytophthora and Pythium caused the most destruction. The heavy rains helped spread those pathogens, says Georgina Sanahuja, a post-doctoral researcher at the UF/IFAS Tropical Research and Education Center in Homestead, FL.
Meteorologists consider Florida’s dry season to run from October 1 to March 1 and the rest of the year to be the wet season. But last year, the dry season wasn’t so dry, because of El Niño, which brought more rain than South Florida has seen since records were kept starting in 1932, according to a new study published in the journal HortTechnology.
When last winter’s rains hit, nursery growers brought their plants to the UF/IFAS Extension Plant Diagnostic Clinic in Homestead. Plants suffered from root rots, crown rots, and blight diseases.
“The ornamental industry has exceedingly high standards for plant quality, and there is often zero tolerance for disease symptoms caused by plant pathogens,” Sanahuja says.
In the study, Sanahuja — in collaboration with Vanessa Campoverde, a commercial agriculture and ornamentals agent with UF/IFAS Extension Miami-Dade County — documented four years of environmental conditions in South Florida that caused the plants to get diseases. They studied October 1 to March 1 of 2015-2016 and compared it with the same period from the three previous years.
UF/IFAS experts suggest nursery owners and managers routinely scout for root rot, crown rot, and blight diseases. Diseases caused by Pythium and Phytophthora spread quickly and require chemical applications when the weather forecast calls for heavy rains, Sanahuja says. UF/IFAS experts also recommend removing and discarding severely affected plants, and using proper fertilization and irrigation for better plant health.