The Bug Box: Phytoplasma disease of poinsettia

Clemson University

Clemson University

This bug is creeping around your property. He may be friend or foe.

Name: Family Mycoplasmataceae

Alias: Phytoplasma disease of poinsettia (PoiBI). There are many diseases caused by phytoplasmas. Common symptoms are stunting, yellowing, reduced quality, reduced yield and proliferation of shoots. The organism is bacterialike, but it lacks a cell wall. These organisms are usually transmitted by leafhoppers and plant hoppers. But n the case of poinsettia, it is difficult to describe the infection as a plant disease. Uninfected poinsettias grow 8 to 10 feet tall and have few branches, yet the infected plants we buy at this time of year are short and multibranched.

Crimes: This all depends on your point of view. Most mycoplasms are damaging to crops and difficult to control. In the case of the poinsettia, however, they are put to a good use. Truly beautiful, many wish to keep the poinsettia as a beautiful houseplant. Phytoplasmas are fairly host -specific.

Redeeming Qualities: Truly the Christmas flowering plant.

Sentence: If you’re not patient, you should discard the plant after the leaves start to fade and fall. Should you wish to keep your poinsettia and have it flower the next year, you need to do the following: After leaves yellow, put plant in a dry place without watering it with temperatures of 50 to 60 degrees. In late May, begin watering and cut it back to 6 to 8 inches. Repot with new soil. Water well and place in the sun with temperatures of about 70 degrees. Water sparingly at first; increase with growth. Place it outdoors but watch for frost. In early August, cut back to three strong branches. Bring indoors in early September and keep in sunny spot until early October. It is then critical that the plant has 12 to 14 hours of complete darkness per day. Continue this for 10 weeks and then you’ll have poinsettia blossoms by Christmas.

For more information on dangerous and beneficial bugs, call agent Wayne Jones at the Bonneville County Extension Office at 208-529-1390.