Clivia Pest and Disease Control Methods and Repotting and Division Techniques

Symptoms: Under prolonged high-humidity conditions, the leaves and flowers develop large water-soaked brown rot patches. Hidden within the diseased areas is a white mold layer that is difficult to spot; when dry, the diseased areas turn grayish-brown. Similar symptoms appear when the leaf stalks and flower stalks are infected.

Disease characteristics: This disease is caused by a fungus. The pathogen is a species of Phytophthora (Phtyophthora). The pathogen overwinters in the soil or potting mix, and in the second year spreads via rainwater or water splashing from watering. It is prone to occur when the temperature is around 20°C and there is continuous rainfall or high air humidity. It also frequently occurs when humidity is high in winter greenhouses or when humidity is heavy in spring as temperatures rise.

Control methods:

(1) Horticultural control: After watering, ventilate promptly and appropriately to prevent moisture from lingering, which can reduce disease incidence.

(2) Chemical control: Spray promptly at the early stage of the disease. Options include 70% Baidefu wettable powder at 600 times dilution, 58% metalaxyl-mancozeb wettable powder at 700 times dilution, 64% Shadufan wettable powder at 600 times dilution, 72% Kelu or Keshuangqing or Kekangling wettable powder at 600 times dilution, and 69% Anke-mancozeb wettable powder at 800-900 times dilution. Spray once every 10 days or so, for 2-3 consecutive applications.