Fungus

Sigatoka leaf spot is a devastating fungal disease that affects banana plants, especially the popular Cavendish variety. It is caused by fungi belonging to the Mycosphaella genus, with Mycosphaerella physiensis (Black Sigatoca) and Mycosphaerella musicola (Yellow cigatoca) being the most prominent species responsible for this disease. Sigatoka leaf spot is a significant threat to banana cultivation worldwide.

Symptoms of Sigatoka Leaf Spot

Sigatoka leaf spot is manifested through specific symptoms that mainly affect the leaves of the banana plant. As the disease progresses, these symptoms grow in different stages:

Yellow spots: Initially, small yellow spots appear on the lower leaves, which are the oldest. These spots are the first visible sign of infection and are often ignored.

Black spots: As the disease progresses, these yellow spots develop into dark, angular spots with a yellow halo. These spots are the specific spots that give the disease its name. Over time, the darker spots enlarge and merge to form a wider necrotic area on the leaves. It severely affects the photosynthesis and overall health of the plant.

Premature leaf sterilization: Severe infestation causes premature leaf decay, reducing the plant's ability to produce energy and limiting fruit growth.

Also read: Panama wilt disease has affected banana crop in these regions of India

Reduced fruit quality and yield: Ultimately, sigatoka leaf spot significantly reduces both the quality and yield of the banana crop. Severely affected plants produce small, deformed fruit or sometimes fail to produce fruit.

Dispersion and impact

Sigatoka leaf spot is spread mainly through spores produced on infected leaves. Wind, rain, and human activities help these spores to spread long distances. If not managed, the disease can lead to yield losses of up to 50-70%, a major concern for banana farmers around the world.

How to manage Sigatoka leaf spot disease?

Effective management of Sigatoka leaf spot is important to reduce its impact on banana cultivation. Integrated disease management (IDM) strategies are often employed, combining different approaches to control and prevent the spread of disease. The following are the key components of IDM for Sigatoka Leaf Spot:

1. Various agricultural operations

Crop rotation: Banana cultivation should be avoided at one place continuously. Rotate with other crops to disrupt the life cycle of the disease.

Distance and pruning: Proper spacing between plants and pruning dry and diseased leaves improves air circulation, reduces humidity and prevents the growth of pathogenic fungi.

Hygiene: Remove and destroy infected leaves to prevent the spread of disease. This involves timely removal of more sensitive old leaves.

2. Resistant varieties

Use banana varieties that exhibit some degree of resistance to Sigatoka leaf spot. While complete resistance is rare, resistant varieties can still reduce the severity of the disease.

3. Chemical Control

Fungicides are often used in commercial banana cultivation to manage the Sigatoka leaf spot. Regular use of fungicides helps in controlling the disease. However, responsible use of fungicides is important to prevent resistance growth and reduce environmental impact. After research conducted at various centers of the country under ICAR-All India Coordinated Research Project (FRUIT), it was found that mineral oil 1% + any one of the following fungicides like Propiconazole (0.1%) or combination of Carbendazim + Mancozeb (0.1%) or Carbendazim (0.1%) or Trifloxystrobin + Tebuconazole (1.4 gm per liter) sprayed 5-7 times according to the severity of the disease at an interval of 25-30 days can easily manage the disease This led to a 20% increase in yield. Mineral oil used for spraying is a biodegradable oil.

4. Biological Control

Some beneficial microorganisms help suppress Sigatoka leaf spot fungus. Research is ongoing to develop effective biological control methods.

Also read: How to prepare bananas before sending them to the market to get maximum benefit?

5. Monitoring and early detection

Inspect the banana plants regularly for early signs of infection. Early detection makes it possible to intervene in time, which helps in disease control.

6. Weather Based Disease Forecasting

Weather data and disease modeling are currently being used to predict Sigatoka leaf spot outbreaks in the region. This information helps farmers plan fungicide use more effectively.

7. Genetic improvement

Research on developing banana varieties with improved resistance to the Sigatoka leaf spot is ongoing. This approach aims to provide a long-term solution to the disease.

8. Education and Training

Training farmers in disease identification and appropriate disease management measures is essential to effectively control Sigatoka leaf spot.

 Also read: Farmer quits job in Switzerland to start banana cultivation, today turnover is 100 crores 

Challenges and future directions

The management of Sigatoka leaf spot remains a complex challenge due to the disease's ability to develop resistance to fungicides, its rapid spread, and limited availability of resistant banana varieties. Additionally, environmental concerns associated with chemical control methods highlight the need for sustainable and environmentally friendly solutions.

In the future, continued research and development efforts are crucial. This includes breeding programs, improved disease prediction models and the discovery of innovative biological control methods to develop more resistant varieties of bananas. Education and access to farmers is equally important to ensure adoption of best practices in disease management.

In conclusion, it can be said that Sigatoka leaf spot is a serious threat to banana cultivation globally. Effective disease management requires a holistic approach that combines agronomic action, resistant varieties, chemical and biological control methods, surveillance, and ongoing research. By implementing these strategies, banana farmers can reduce the impact of the Sigatoka leaf spot and protect their crops, livelihoods, and the banana industry as a whole.

In the world, apart from India, Parwal is cultivated in China, Russia, Thailand, Poland, Pakistan, Bangladesh, Nepal, Sri Lanka, Egypt and Myanmar. In India, Parwal is cultivated in the states of Uttar Pradesh, Bihar, Assam, West Bengal, Orissa, Madhya Pradesh, Madras, Maharashtra, Gujarat, Kerala and Tamil Nadu. In Uttar Pradesh, Parwal is cultivated on commercial level in Jaunpur, Faizabad, Gonda, Varanasi, Ghazipur, Ballia and Deoria districts, whereas in Bihar, Parwal is cultivated commercially in Patna, Vaishali, Muzaffarpur, Samastipur, Champaran, Sitamarhi, Begusarai, Khagaria, It occurs in Munger and Bhagalpur.

 In Bihar, it is cultivated in the plains and Diara areas. During the rainy season, fruit, leaf and root rot diseases are more common in Parwal, the main reason for this is the high humidity in the environment. This disease occurs on a large scale in all the major Parwal growing areas of the country. The severity of this disease is seen in almost all Parwal producing areas. 

This disease is not only seen in the crops standing in the field, apart from this, this disease is also seen when the fruits are plucked. Wet dark colored spots are formed on the fruits, these spots grow and rot the fruit and these rotten fruits start smelling, the fruits which are close to the ground are more diseased. Cotton-like fungus is visible on rotten fruits.

Causes of root and stem rot in Parwal

Fungal pathogen: More than one pathogen is responsible for root and vine rot in Parwal. Phytophthora melonis causes rotting of fruits, leaves and roots of Parwal (Trichosanthes dioica). Apart from this, Rhizoctonia solani, various species of Fusarium and various species of Pythium are also the main causes behind root and vine rot in Parwal. There are reasons. These pathogens thrive in hot and humid conditions, making the crop vulnerable, especially during the rainy season.

Also read: Farmers can earn good money in a short amount of time by growing parwal

Poor drainage: Waterlogged soils or inadequate drainage systems create ideal environments for fungus growth. Excess moisture around the roots and vines promotes the development of rot. 

Contaminated soil and planting material: Using contaminated soil or infected planting material can introduce pathogens into the crop. Proper soil sterilization and use of disease-free seedlings are essential preventive measures.

Effect of rotting on Parwal

Reduction in yield: Root and vine rot can significantly reduce crop yield. Infected plants may produce small, deformed fruits, or in severe cases, fail to produce harvestable produce.

Economic loss: For farmers, lower yields mean lower income. The costs of inputs such as seeds, fertilizers and labor are not compensated, leading to financial losses.

Crop Quality: The quality of Parwal can be compromised even if the crop survives. Rotten vines and roots affect the taste and texture of the vegetable, making it unmarketable.

How to manage root and stem rot disease in Parwal?

Effective management of root and vine rot in Parwal involves a combination of preventive and curative measures. To solve this problem, some solutions are as follows:

Also read: Started production off parwal after learning from farming university, earning of upto 80 thousands

Crop rotation and site selection

Implement crop rotation system to break the disease cycle. Avoid planting Parval in the same soil for consecutive seasons. Choose well-drained, elevated planting sites to reduce the risk of waterlogging.

Preparing the soil

Before planting, make sure the soil is properly prepared. Incorporate organic matter such as compost to improve soil structure and drainage. Use soil solarization, a technique where plastic sheets are used to trap heat and kill soil-borne pathogens before planting.

Seed selection and treatment

Use disease-free planting material from reputable sources. Treat the planting material with fungicide before transplanting to reduce the chance of fungal infection.

Proper water management

Irrigate the crop carefully, avoiding excessive moisture around the roots and vines. Use drip irrigation to deliver water directly to the root zone, reducing fungal contact.

Also read: All information regarding drip irrigation

Use of fungicide

Use fungicides as a preventive measure, especially during the early stages of plant growth. To control this, fruits should not be allowed to come in contact with the ground. For this, straw or reeds should be spread on the ground. Spraying fungicide containing Ridomil and Mancozeb mixed with Ridomil M Gold, 2 grams per liter of water and thoroughly wetting the soil around Parwal with this solution reduces the severity of the disease. 

It is worth noting that Parwal fruits should be harvested only after 10 days of spraying the medicine. All pluckable fruits should be plucked before spraying the medicine. The schedule for spraying the medicine should be decided only after the weather forecast, because if it rains immediately after spraying the medicine, the expected benefits will not be achieved. Consult agricultural experts for guidance on proper fungicide and application schedule.

Controlling the organic matter

Use beneficial microorganisms such as various species of Trichoderma that help suppress pathogenic fungi.

Cleanliness

Practice good field sanitation by removing and destroying infected plant debris. This prevents the formation of pathogens in the soil. Disinfect tools and equipment to prevent the spread of disease.

Fungus resistant varieties of parwal

If available, choose Parwal varieties that are resistant to root and vine rot. Resistant varieties can reduce the risk of infection to a great extent.

Also read: 3 new types of parwal developed in this state

Nutrient management

Maintain balanced levels of nutrients in the soil. Plants lacking nutrients are more susceptible to diseases. Regularly monitor and adjust fertilizer application based on soil testing.

Training and education of farmers

Train farmers in disease identification and management techniques. Establish local support networks and extension services for timely advice and assistance.

Weather monitoring

Keep an eye on weather conditions, especially during the rainy season. Apply preventive measures when conditions are favorable for fungal growth. To conclude, root and vine rot in Parwal can be challenging for farmers, but with the right management strategies, its impact can be minimized. Preventive measures such as crop rotation, soil preparation and proper water management are important. 

Additionally, the use of disease resistant varieties and biological control methods can further increase crop resilience. By taking a holistic approach to disease management and staying informed about best practices, farmers can protect their Parval crops and ensure a safer and more profitable harvest.