Causes and Control Methods of Soft Rot in Clivia

Clivia has an elegant and exquisite appearance and is deeply loved by scholars and writers both in ancient and modern times, in China and abroad. Clivia is a relatively easy plant to keep alive, but it is inevitably prone to "getting sick." The following are the methods.

Symptoms: Bacterial soft rot in Clivia mostly occurs on the middle and lower leaves of the plant. The lesions initially appear yellow-green, water-soaked and transparent, then turn brown and soft-rotted; the lesions are irregular, with a clear boundary between diseased and healthy tissue. Bacterial ooze flows out from the wound at the edge of the lesion; in the later stage the lesion dries, shrivels and sinks, and in severe cases the entire leaf drops off.

Occurrence pattern: The pathogen of bacterial soft rot in Clivia is the black rot subspecies of Erwinia carotovora (soft rot Erwinia). The pathogen overwinters on diseased host residues and plant debris, and mostly infects and causes damage through wounds; it occurs more severely under high temperature and high humidity and when there is damage by scale insects.

Control methods: 1. Control soil moisture, improve ventilation and lower the temperature, control scale insects, and reduce mechanical wounds; 2. After the disease occurs, spray with 15% agricultural streptomycin wettable powder at 500 times dilution or with 20% thiacloprid (Longkejun) wettable powder at 600 times dilution for control, once a week, for 2-3 consecutive sprays.