How to prevent and treat root rot in large-flowered clivia (Clivia miniata)? A detailed guide to practical methods

Distribution and damage

It mainly harms the seeds, seedlings and mature plants of large-flowered clivia.

Symptoms

It occurs from time to time on seeds, seedlings and mature plants. After sowing, due to low temperature and high humidity, seed germination is prolonged; after the radicle is infected by pathogens, it turns brown to grayish brown, becomes sunken and soft, and rots. In some cases the rot reaches the endosperm, leaving the seed an empty shell. When seedlings and mature plants are infected, the roots turn grayish brown or brown, and later become hollow, with only the epidermis remaining, so they cannot absorb water; in severe cases the roots rot away completely.

Pathogen

Fusarium marticlla Wr., called Fusarium, is a deuteromycete fungus. In addition, excessive watering first causes root suffocation, and over time it can also cause root rot; mixing Bordeaux mixture with carbofuran can also trigger heart rot in clivia.

Occurrence pattern

The pathogen overwinters in the soil. When spring is cold, the soil temperature stays low for a long time, or there is excessive watering and high humidity, especially when cold waves strike frequently, root suffocation is likely to occur. Applying insufficiently decomposed organic fertilizer causes root burn. If root suffocation or root burn lasts a long time, it induces Fusarium invasion and leads to root rot.

Prevention and treatment methods

(1) Careful cultivation. Clivia likes cool conditions. The suitable daytime growing temperature is 14-25°C, the night temperature is about 15°C, and the overwintering temperature should be above 5°C. During the bud stage, the soil temperature should be kept at 20°C; it should not be too high or too low. Above 30°C is unfavorable for growth and makes the plant prone to disease. During the vigorous growing season, the potting soil should be kept moist, but not waterlogged. Some people fear root rot in clivia and control water excessively, causing insufficient water, which affects normal growth and development and leads to dull leaves with dry tips, "arrow clamping" during the flowering period, or shrinkage of the fleshy roots. During the seedling stage, do not water too much. When clivia enters dormancy, it should not be watered; otherwise root rot occurs below the soil and yellowing leaves caused by root rot appear above ground, making the plant prone to root rot.

(2) The growing medium is required to be fully decomposed, loose and fertile, with strong permeability. Clivia should not be given farmyard manure or chemical fertilizer. For pot cultivation, it is best to use a special fertilizer for clivia or leaf mold from under broad-leaved forest. Perilla seeds can also be fried until cooked and buried at the bottom of the pot when changing the soil. Except in the hottest or coldest seasons, apply organic decomposed liquid fertilizer once every half month, alternating types. If the maintenance temperature is above 25°C, stop or reduce fertilizing; otherwise the plant cannot absorb it and root rot may result.

(3) Clivia likes a semi-shaded environment. Receiving sunlight in autumn and winter is beneficial for flower bud differentiation. From May to June, when sunlight is direct, clivia should be shaded, and the relative humidity should be kept at 60-70%. At the end of autumn, after a period at around 10°C, bring it indoors, and after bringing it indoors keep the air fresh and humid.

(4) To prevent root rot, start from the seedling stage and use the germination-promoting sowing method. The seedling substrate, sand or sawdust, should be boiled for 30 minutes, and the seedling temperature should be controlled at 15-25°C. If root rot appears on mature plants or seedlings, replace the substrate promptly and perform surgical treatment. After removing the plant from the pot, cut off the discolored parts and rotten roots. It should not be potted immediately. Place the plant in a clean spot at 5-10°C, and after the root wounds heal and there are no signs of continued rotting, pot it again. After potting, use the wet-soil dry-planting method, and water only after the potting soil has dried completely; this makes the operation more likely to succeed. Do not repot too frequently; in general, changing to a clay pot once every 3-5 years is enough.

(5) At the early stage of disease, spray or drench with 50% Likuqing wettable powder at 800-900 times dilution, or 50% Genfuling wettable powder at 800 times dilution, 50% Shajunwang water-soluble powder at 1000 times dilution, 95% Lüheng No. 1 premium at 3500 times dilution, or 80% Duo-Fu-Xin wettable powder at 700-800 times dilution. Plant Power 2003 can also be used, with 1 kg of water per milliliter, or Yunda-120 plant growth regulator at 3500 times dilution.

(6) For other methods, see base rot of golden-edged daphne (Daphne odora 'Aureomarginata').