Overview of Stevia rebaudiana (Bertoni) Bertoni
Stevia rebaudiana (Bertoni) Bertoni, commonly known as sweetleaf or simply stevia, is a plant species native to South America. It is a member of the sunflower family and is well-known for its sweet-tasting compounds. The plant is primarily used as a natural sweetener, with an increasing number of consumers turning to it as a healthy alternative to sugar and artificial sweeteners.
Appearance of Stevia rebaudiana
The stevia plant is a short, herbaceous perennial that measures between 30-60 cm in height. It has small, serrated leaves that are typically 1-2 cm in length and a greenish hue. Stevia blooms in the early summer, producing small, white flowers that grow in clusters.
Common Uses of Stevia rebaudiana
As previously noted, the stevia plant is primarily used as a natural sweetener. It contains compounds called steviol glycosides that are estimated to be 300 times sweeter than sucrose (table sugar). These compounds do not affect blood sugar levels, making stevia an ideal sugar substitute for diabetics. Stevia is also often used in the production of various foods, including baked goods, beverages, and sweetened snacks. Additionally, some research has suggested that stevia may have other potential health benefits, including anti-inflammatory properties and the ability to lower blood pressure.
Light Requirements:
Stevia rebaudiana requires full sunlight to grow properly. It needs at least 6-8 hours of direct sunlight every day to produce large and healthy leaves. Insufficient sunlight can result in elongated stems, small and weak leaves, and spindly growth. On the other hand, too much sun exposure can lead to leaf scorching and dehydration of the plant.
Temperature Requirements:
Stevia rebaudiana grows best in warm temperatures ranging between 20°C to 30°C. It cannot tolerate freezing temperatures or frost. Extreme heat can also be harmful to the plant. Temperatures above 35°C can cause the plant to wilt and die. Additionally, fluctuations in temperature can lead to stunted growth and poor harvests. Therefore, it is crucial to maintain a consistent temperature range throughout the growing season.
Soil Requirements:
Stevia rebaudiana requires fertile and well-draining soil to thrive. The pH of the soil should range between 6.5 to 7.5. Heavy clay or sandy soil can inhibit root development and cause poor growth. Ideal soil should be rich in organic matter, well-aerated, and have good water retention capacity. Additionally, frequent watering is required to keep the soil moist but not waterlogged. Over-watering can lead to root rot and fungal diseases.
Cultivation methods for Stevia rebaudiana
Stevia rebaudiana thrives in warm and sunny environments with good drainage. It can be grown both indoors and outdoors. The plant requires moist soil, and so it is important to water it regularly. The ideal temperature for the growth of Stevia rebaudiana is between 20-30 degrees Celsius. It can be grown from seeds or through stem cuttings, and the plant reaches maturity after one year.
Watering needs for Stevia rebaudiana
Stevia rebaudiana requires regular watering, and it is important to keep the soil moist. However, overwatering can lead to the root rot of the plant. It is recommended to water the plant once a day, especially during the hot and dry seasons. If the environment is too humid, then the plant can survive with once every two days watering schedule.
Fertilization of Stevia rebaudiana
Stevia rebaudiana requires regular fertilization, especially during the growing season. A balanced fertilizer of nitrogen, phosphorus, and potassium can be used once every six weeks. It is important not to over-fertilize the plant as it can lead to a reduced yield of the plant.
Pruning of Stevia rebaudiana
Stevia rebaudiana can become bushy, and pruning is essential to promote new growth and maintain plant health. Pruning should be done once the plant reaches a height of 20-25cm. The bottom 15cm of the plant can be pruned to avoid the development of woody stems and encourage new growth. Additionally, it is recommended to prune the plant at least twice a year to promote new growth and increase the yield of the plant.
Propagation of Stevia rebaudiana
Stevia rebaudiana is a sweet-tasting plant that belongs to the Asteraceae family. Propagation of Stevia can be done by various methods. The three most common ways of propagating Stevia rebaudiana are by seeds, cuttings, and tissue culture.
Propagation by Seeds
Sowing of seeds is the most common method of growing Stevia rebaudiana. The ideal time to plant the seeds is during spring or early summer. Stevia seeds are tiny and need to be sown at a shallow depth of around ¼ inch. The soil should be kept moist but not waterlogged. The seeds take around ten days to two weeks to germinate. Thin the seedlings so that they grow around 12 inches apart.
Propagation by Cuttings
Cuttings propagation method of Stevia rebaudiana is faster compared to propagating by seeds. Cuttings obtained from the mother plant are rooted in the soil or water. The ideal time to make cuttings is during the plant's active growing season. The cutting should be around three to six inches long, with several leaves. Remove the bottom leaves and place the cutting in the soil or water. The cutting should be kept moist, and within a month, they should have grown a healthy root system.
Propagation by Tissue Culture
Tissue culture is also a method of propagation of Stevia rebaudiana; it involves the use of plant tissues to create new plants. This method requires a laboratory set up and is commonly used to improve the quality of the new plants. Tissue culture allows for the production of consistent, high-quality plants. The process involves cutting and culturing tiny pieces of Stevia material onto a nutrient-rich culture medium under sterile laboratory conditions. The process takes around 6-8 weeks.
Disease and Pest Management for Stevia rebaudiana (Bertoni) Bertoni
Stevia rebaudiana (Bertoni) Bertoni, commonly known as sweetleaf or sugarleaf, is a perennial plant native to South America that is prized for its sweet leaves, which are used as a natural sweetener. While this crop is relatively pest and disease-resistant, several pests and diseases can impact the health and productivity of these plants.
Common Pests
One common pest that affects stevia plants is the spider mite. These tiny mites damage plants by piercing the leaves and sucking out the plant sap, causing yellowing and wilting of the leaves. To manage spider mites, apply a neem oil-based insecticide or a mixture of water and dish soap to the foliage. Biological pest control, such as introducing ladybugs, can also help control spider mites.
The whitefly is another common pest that can infest stevia plants, causing stunted growth and leaf yellowing. These pests are often difficult to control, but insecticidal soaps and neem oil-based insecticides can help reduce populations. Introducing parasitic wasps and ladybugs can also help control whitefly infestations.
Common Diseases
Stevia plants are susceptible to several common diseases, including powdery mildew, leaf spot, and downy mildew. Powdery mildew appears as a white powdery substance on the leaves, while leaf spot causes brown or black spots on the foliage. Downy mildew can cause yellowing and wilting of the leaves.
To manage these diseases, avoid overhead watering and keep the foliage dry. Remove infected plants and dispose of them properly. Apply a fungicide containing copper or sulfur to the plants, following the manufacturer's instructions carefully.
Another common disease that affects stevia plants is root rot, caused by overwatering or poorly-draining soil. The roots of infected plants appear brown and mushy, and the plant will wilt and die. To manage root rot, improve soil drainage and avoid overwatering. If the infection is severe, remove the infected plant and dispose of it properly.
Overall, by practicing good gardening practices such as regularly monitoring plants for pests and diseases, implementing preventative measures, and promptly treating infected plants, stevia crops can thrive and produce an abundant harvest.
