Cultivation Methods and Pest and Disease Control Techniques for Lisianthus

Growth Habits of Lisianthus

Lisianthus is native to the areas of Colorado, Nebraska, Texas and New Mexico in the United States, and began to become popular as a cut flower in Japan and Korea and other places starting in the 1970s. It prefers a warm, humid environment with plenty of sunlight, is relatively drought-tolerant, and is not tolerant of waterlogging. It has strict requirements for water and prefers humidity, but too much water is also detrimental to root growth. It is relatively sensitive to light, and requires loose, fertile and well-drained soil, with a pH of 6.5 to 7.0 being suitable.

Propagation Methods for Lisianthus

Lisianthus is commonly propagated by sowing. Its seeds are very small, usually about 10,000 seeds per gram, so lisianthus seeds are mostly coated. Coated seeds have a relatively high emergence rate. It is best to sow indoors in pots in September to October or January to February. The seeds are light-loving and do not need to be covered with soil. The suitable germination temperature is 22 to 25°C, and they germinate 12 to 15 days after sowing. About half a month after germination, thin out or transplant the seedlings. The seedlings grow very slowly. It takes 120 to 140 days from sowing to flowering, and 150 to 180 days for cut flower varieties. In the seedling market, a small number of tissue-cultured seedlings and cuttings of lisianthus are also available.

Cultivation Methods for Lisianthus

1. Soil: Lisianthus requires fertile, loose and well-drained soil. Continuous cropping must be avoided. The soil used for pots must be sterilized; the soil can be treated with high-temperature steam or methyl bromide, and the suitable soil pH is 6.5 to 7.0.

2. Light: Lisianthus is relatively sensitive to light. Long-day conditions are very favorable for the growth and development of lisianthus, helping stem and leaf growth and flower bud formation. Generally, 16 hours of light per day gives the best results.

3. Temperature: Lisianthus prefers warmth. The suitable growth temperature is 15 to 28°C, and the nighttime temperature during the growing period should not be lower than 12°C. When the winter temperature is below 5°C, the leaf rosette becomes rosette-shaped and cannot flower. It can also tolerate short periods of 0°C low temperature. When the temperature during the growing period exceeds 30°C, the flowering period is noticeably shortened.

4. Watering: Lisianthus likes a humid environment, but excessive water is detrimental to the root growth of lisianthus and makes it susceptible to disease invasion. After the flower buds form, avoid high-temperature and high-humidity environments, otherwise fungal diseases are easily caused. At the same time, insufficient water supply during the growing period results in thin and weak stem and leaf growth and early flowering.

Pest and Disease Control for Lisianthus

1. Stem blight: Spray 1% Bordeaux mixture at the early stage of the disease. In severe cases, alternately use 50% thiophanate-methyl wettable powder at 500 times dilution and 50% baicaoqing wettable powder at 500 to 800 times dilution, spraying once every 3 to 5 days. In addition, pay attention to strengthening ventilation and light transmission, reducing plant planting density, applying nitrogen fertilizer reasonably, appropriately increasing phosphorus and potassium fertilizer, and improving the disease resistance of the plants.

2. Root rot: Root rot mainly infects the roots and root crown. When the disease occurs, black necrotic spots form on the root crown, and in severe cases the plant dies. The spread of this fungus mainly depends on soil, fertilizer, watering and so on. Apply thoroughly decomposed fertilizer, water appropriately, and avoid water accumulation. At the early stage of the disease, 50% carbendazim wettable powder at 600 times dilution can be used, spraying once about every 10 days for 2 to 3 consecutive times.

3. Pests: The main pests of lisianthus are leafminers and aphids, which can be killed with BT biological preparations. Aphids can also be controlled by spraying 50% phoxim at 1000 times dilution or 40% omethoate emulsifiable concentrate at 1000 to 1500 times dilution.