Posting Date: February 22, 2010
A Beauty Takes a Bath
I don't mean to shock you, but about a year ago, something happened to me that doesn't often happen to "ladies of a certain age": I fell in love.
Now, don't worry that you're about to hear anything especially torrid, because my husband fell in love at exactly the same time, and with the exactly the same "girl." Her name is Indra (we call her "Indy" for short), and she's a classic 1974 sailboat — slim, elegant, graceful, a real beauty inside and out.
Fortunately, the previous owner had done a lot of restoration work, but even if you're buying a new sailboat right out of the boatyard, it's going to take a lot of time and often a lot of money getting her "just right." And no, you wouldn't be the first one to break the news to me that "BOAT" stands for "Break Out Another Thousand."
Rhizoctonia, a fungal disease that is an annual problem in azalea cultivars grown in containerized nursery production in the southern and eastern United States can be eliminated by placing plant cuttings in a hot water treatment, according to new ARS research.
It wasn't until we were driving our frozen selves home from the marina that we had one of those "smack yourself on the forehead" moments: Maybe that single battery that runs the part "the rest of the time" ... was dead. The lesson here: Always look for the simple solution (like a dead battery) first.
That's why I was so intrigued when I read about a treatment devised by Agricultural Research Service (ARS) scientists to treat Rhizoctonia, a fungal disease that plagues many ornamental plants. This is so simple that it's mind-boggling: You can eliminate Rhizoctonia in azaleas by placing plant cuttings in ... hot water!
Yes, that's all there is to it. The ARS scientists found that placing the azalea cuttings in water at 122 degrees Fahrenheit for 20 minutes is the most effective method of eliminating Rhizoctonia without damaging the plant, thus eliminating the need for treatment with chemical fungicides. The pathogen can be killed in less time if you use hotter water, but as the water temperature goes up, so does the risk of damaging the cutting.
Unfortunately, Rhizoctonia — like death and taxes — seems to be always with us. Rhizoctonia web blight is an annual problem in azalea cultivars grown in containerized nursery production in the southern and eastern United States. This fungus can live on all plant surfaces as well as pine bark soil, and it thrives throughout the year. But it only causes plant damage in July and August when heat and humidity are at their highest levels.
However, the disease is already doing its damage well before that, attacking the azalea's internal leaves in June, with signs often unseen by the grower. What can't be missed is the stage when a plant goes from looking healthy to having one-third of its leaves rapidly turn brown and die, often in a 24-hour period.
You can't see Rhizoctonia, so it's easy for this fungus to hitch a ride on stem cuttings used to propagate new plants, enabling this pathogen to circulate within nursery stock for years. Right now, nurseries try to fight back by dipping stem cuttings in a disinfectant or a fungicide solution, but even that hasn't controlled the spread of this fungal pest. New methods are definitely needed!
Hot water doesn't solve the problem forever, because there's always the potential for the plant cuttings to become recontaminated again at some later point in the production procession. But the ARS scientists haven't ended their search for answers: Now they're busy identifying the steps in production that pose the greatest risk for recontamination.
Stay tuned for a complete game plan for stopping this fungus in its invisible tracks!
The Agricultural Research Service is the chief in-house scientific
research agency of the U.S. Department of Agriculture. You can read
more about ARS discoveries at http://www.ars.usda.gov/news/.
About the author
"Everybody's
Science" is written by Sandy Miller Hays, Director of Information for
the Agricultural Research Service, the chief scientific research agency
of the U.S. Department of Agriculture. Hays is a native of Fort Smith,
Ark. From the late 1970s until early 1988, Hays was a reporter, editor
and columnist at the Arkansas Democrat (now the Arkansas Democrat-Gazette),
a Little Rock-based daily newspaper. She joined the ARS Information
Staff in 1988, and became Director of Information in April 1998.