Penyakit Blas Padi - Kupas Tuntas

Summary

This video provides an in-depth guide on managing Rice Blast Disease (*Pyricularia grisea*), a major threat to rice crops. It covers the disease’s symptoms, lifecycle, and environmental conditions that promote its spread. The video emphasizes preventive measures such as selecting healthy seeds, using the Jajar Legowo planting technique, balanced fertilization, and applying biological agents like *Pseudomonas* bacteria. It also discusses the use of fungicides for controlling outbreaks. Farmers are encouraged to take proactive steps for effective disease management to protect their rice crops and ensure better yields.

Takeaways

• 😀 Blas disease in rice is caused by the fungus *Pyricularia grisea*, which affects both the vegetative and generative stages of the rice plant.
• 😀 During the vegetative stage, Blas disease causes characteristic brown lesions on rice leaves, shaped like diamonds or kites.
• 😀 In the generative stage, Blas attacks the panicle neck, causing it to rot, turning yellow, and preventing the grains from filling, leading to empty rice kernels.
• 😀 The disease spreads quickly, with spores being released primarily in the early morning hours (2-6 AM), and can be dispersed by wind or water.
• 😀 Blas thrives in humid conditions with temperatures between 22-25°C and a long dew period during the night, making it common in tropical climates and rainy seasons.
• 😀 Excessive nitrogen fertilization increases the plant’s susceptibility to Blas disease by weakening its cell walls, making it easier for the fungus to penetrate.
• 😀 The disease can persist in dry rice straw and infected rice grains for up to three years, making crop rotation and good field hygiene critical for control.
• 😀 Effective prevention methods include using healthy seeds, practicing the Jajar Legowo planting method, and ensuring proper spacing to reduce humidity and improve airflow.
• 😀 Soil preparation should be done well in advance of planting (e.g., one month before) to help kill spores present in the leftover rice straw through decomposition.
• 😀 Chemical fungicides like Tricyclazole, Methyl Thiophanate, and Carbendazim are recommended for controlling Blas disease, particularly during critical stages like the peak tillering and early flowering phases.

Q & A

What is rice blast disease, and what causes it?

Rice blast disease is caused by the fungus *Pyricularia grisea*, which affects rice plants at various stages of their life cycle. It leads to characteristic symptoms such as brown lesions on leaves and grain discoloration, often resulting in plant death or hollow grains.

What are the symptoms of rice blast disease on rice plants?

In the vegetative stage, rice blast causes brown, diamond-shaped lesions on the leaves. During the generative stage, it affects the neck of the panicle, causing it to rot, which leads to incomplete filling of the rice grains, making them hollow.

How does the *Pyricularia grisea* fungus spread?

The fungus spreads through wind and water. It also survives in infected rice debris, such as sick grains and straw, and can remain viable for up to a year in dry conditions. The spores are typically released in the early morning or after rainfall.

What environmental factors contribute to the development of rice blast disease?

Rice blast thrives in warm, humid environments with temperatures ranging from 22°C to 25°C during the night. A long dew period and high humidity also promote the development of the disease, especially during the rainy season.

How does excessive nitrogen use affect the spread of rice blast disease?

Excessive nitrogen fertilization can weaken the plant's defense mechanisms, making it more susceptible to infection by *Pyricularia grisea*. High nitrogen levels increase cell permeability in the plant's epidermis and reduce silica content, which facilitates fungal penetration.

What farming practice can help reduce the spread of rice blast disease?

Using the *Jajar Legowo* planting method helps reduce the risk of rice blast by increasing spacing between plants, improving air circulation, and reducing humidity around the plants. This makes it harder for the disease to spread from one plant to another.

How can farmers prevent rice blast disease from spreading through seed?

Farmers should use healthy, disease-free seeds. One way to ensure this is by treating the seeds with biological agents, such as *Pseudomonas*, or using fungicides to reduce the chance of disease transmission from infected seeds.

Why is land preparation important in preventing rice blast disease?

Proper land preparation helps to kill off fungal spores present in the rice debris from previous crops. By decomposing the plant material, the temperature of the soil rises, which can reduce or eliminate the spores, lowering the risk of infection.

What role does silica play in managing rice blast disease?

Silica helps strengthen the physical defenses of the plant, particularly the epidermal cells, making it harder for the *Pyricularia grisea* fungus to penetrate the plant. Silica is most effective when applied before the disease attacks the plant.

What types of fungicides are recommended for controlling rice blast disease?

Fungicides such as *Tricyclazole*, *Methyl Thiofanate*, and *Difenoconazole* are recommended for controlling rice blast. These chemicals should be applied at critical stages, such as during the peak tillering and early flowering phases, to prevent the disease from affecting the plant.