Miami, Florida — Costa Farms, the leading bedding and indoor houseplant grower in North America, is getting ahead of the downy mildew disease that is infecting Impatiens walleriana or standard garden impatiens.
“Downy mildew is only infecting Impatiens walleriana,” explains Dr. Kate Santos, director of research and development for Costa Farms. “Gardeners can be assured it is not infecting other plant species like New Guinea Impatiens and SunPatiens.”
Plasmopara obducens, the type of downy mildew that’s attacking impatiens, has been reported in several states and first made its appearance in the Palm Beach County area of Florida in late 2011. At this time, downy mildew cannot be cured after it is detected; only prevented.
“The best defense is a strong offense so we at Costa Farms have initiated a 3-prong approach to alert people about the disease, prevent infestation, and provide alternatives to have healthy, beautiful plants in their landscape,” explains Santos. “We’re determined to help contain and minimize the spread of this disease.”
Know the symptoms. The time from infection to the appearance of symptoms varies from about 5 to 14 days. Be on the lookout for early leaf symptoms of the disease.
Laura Sanagorski and Bill Schall, environmental and commercial horticulture extension agents at the University of Florida’s IFAS Palm Beach County Extension, reported that young plants and new growth are most susceptible to the disease.
“Signs are yellow or light green foliage with speckling on the infected leaves, and then a white, downy-like growth composed of spores visible on the underside of the infected leaves,” explains Santos.
Santos warns that sometimes the first sign is a downward leaf curling. She says if unchecked, eventually the leaves and flowers will drop, resulting in bare stems with only a few tiny, yellow leaves remaining.
One of the keys is weather. “Cool temperatures, moist air and wet foliage are ideal conditions for the disease that is spread by air or water movement,” says Santos.
An ounce of prevention. Sanagorski and Schall suggest that prevention is the most effective management strategy. They recommend eliminating nighttime watering and excessive fertilization to help avoid or reduce the occurrence of the disease.
“If infected impatiens are discovered, immediately remove the entire plant-roots, leaves and top part of plants, put into a plastic bag, tie it off and dispose,” explains Santos.
Costa Farms is currently using preventative measures that will protect its crops from downy mildew for several weeks after leaving the farm.
“Consumers can feel confident that Costa Farms is employing every measure to protect the plants prior to leaving the farm,” says Santos. “We’d like to remind consumers to only plant impatiens in beds that have not previously shown symptoms of downy mildew.”
Alternatives. The good news is there are plenty of bedding plants that are ideal replacement for standard impatiens.
“If your impatiens are in the shade you may lean to begonias or New Guinea Impatiens,” says Santos, “and if your garden is in the sun, plant SunPatiens, phlox and petunia or lobelia.
“Remember, check your bedding impatiens and use alternative flowers to create that wow color you love for your garden this year,” she adds.
For more information or to see a gallery of alternative flowers to replace, visit www.costafarms.com.
About Costa Farms:
Costa Farms is the largest producer of indoor houseplants in the world. Founded in 1961 by Jose Costa, Costa Farms is a third generation, family owned business that globally stretches over 3,800 acres and employs 2,800 people. Along with thriving indoor and bedding plant divisions, Costa Farms operations are located in Florida and North Carolina, and abroad in the Dominican Republic, and Far East.
Source: Costa Farms
