December 1, 2007
The major bacterial disease of Phalaenopsis orchids in Florida is the bacterium Erwinia carotovora (L.R. Jones) Bergey et al. subsp. carotovora (L.R. Jones) Bergey et al. Major economic damage occurs during environmental conditions that favor E. carotovora soft rot disease, such as warm to hot temperatures combined with high moisture. This bacterium spreads through rain or overhead irrigation splash, which allows plant-to-plant movement. Phalaenopsis are generally planted with two plants per 6-inch pot. When plants infected with Erwinia are found in the nursery, the diseased plant is rogued out. A study was initiated in Homestead, FL in 2006 to determine if roguing of diseased plants was effective in reducing plant losses. The study was repeated 5 times and in all cases roguing of a single diseased plant from the pot was not effective.