Don’t let diseases defeat you
Diseases such as collar rot, Rhizoctonia, pythium and target spot will ruin transplants unless controlled. Target spot is of particular concern, because most growers just deal with the disease the best they can, says Stephen Barts, an Extension agent in Pittsylvania County, Va., adding that for target spot control, there is good news. In 2012, growers can apply Quadris in the greenhouse.
Last year — after the greenhouse production season — Quadris received a special local needs 24-C label in Virginia. It is labeled for one over-the-top application.
“That particular product does a great job in the field, so we would expect nothing less out of it in the greenhouse,” Barts says.
He suggests applying Quadris at about the first or second clipping, but it is really too early to tell whether the first or the second clipping is best. More research needs to be done. “What we’re going to have to do this year is actually inoculate some target spot in the greenhouse to figure out when you should spray it, and what the best rate is,” he says.
The labeled rate in the greenhouse is 0.14 fluid ounces per 1,000 square feet, which amounts to 6 ounces per acre.
Even though growers can use Quadris in the greenhouse, Extension still recommends a layby treatment to ward off any target spot in the field.
Growers should be aware of Rhizoctonia and collar rot showing up at first clipping, when dead and decaying plant material can linger. Even after the second or third clippings, these diseases can be a problem because “the vacuum mowers don’t necessarily pull every bit of plant material back up with them,” Barts says. “Little pieces of plant material will end up in the trays and provide that breeding ground. The more you clip, the more you provide conditions that are conducive to having these diseases. That’s part of the management program — trying to seed a little later, minimizing the number of times that you have to clip. It’s cutting down on your diseases, and it’s cutting down on fuel consumption and still having usable transplants.”
This article published in the March, 2012 edition of CAROLINA-VIRGINIA FARMER.