Dieback Disease: A Threat to Neem Trees and Ecosystems

Understanding Dieback Disease

In recent years, the alarming decline of thousands of neem trees has prompted a detailed investigation by the Mulugu-based Forest College & Research Institute (FCRI). This investigation aims to understand the devastating impacts of dieback disease.

What is Dieback Disease?

Dieback disease is caused by a fungal pathogen that affects various plants, leading to severe wilting and browning of leaves, stem cankers, and fruit rot. Initially identified in the 1990s near Dehradun in Uttarakhand, the dieback fungus is classified under the genus Phytophthora.

How Does Dieback Disease Spread?

The primary mode of spread for this fungus includes:

• Movement of soil and mud, especially via vehicles and footwear.
• Transmission through free water and root-to-root contact among plants.

Once established, the fungus resides in vulnerable plant tissues and soil, thriving in warm, moist conditions. Infected roots fail to absorb adequate water and nutrients, leading to dehydration and eventual death of the plant.

Impact on Agriculture and Ecosystems

Dieback disease can result in nearly 100% loss of fruit production in severely affected trees. The disease poses a significant threat to native vegetation, often leading to ecosystem degradation. The delicate balance of these ecosystems can be disrupted, with certain species disappearing from affected areas.

Symptoms and Detection

Symptoms of dieback disease typically emerge with the onset of the rainy season, worsening as the season progresses into early winter. Detection can be challenging, as infected plants may resemble those suffering from drought stress. Unfortunately, there is currently no known cure for dieback disease.

Conclusion

Understanding dieback disease is crucial for protecting neem trees and maintaining healthy ecosystems. Research and awareness are vital in managing this fungal threat effectively.

Frequently Asked Questions (FAQs)

Q1. What causes dieback disease in neem trees?
Answer: Dieback disease is caused by the Phytophthora fungus, which leads to wilting and browning of leaves, stem cankers, and ultimately tree death.

Q2. How does dieback disease spread?
Answer: The disease spreads through soil movement, water, and root contact. It thrives in warm, moist conditions, affecting nearby plants.

Q3. What are the symptoms of dieback disease?
Answer: Symptoms include leaf wilting, browning, stem cankers, and fruit rot. Detection can be difficult as symptoms may mimic drought stress.

Q4. Is there a cure for dieback disease?
Answer: Currently, there is no known cure for dieback disease, making prevention and management crucial for affected areas.

Q5. How can dieback disease impact ecosystems?
Answer: Dieback disease can lead to significant loss of native vegetation, disrupting ecosystems and potentially causing species extinction in affected areas.

UPSC Practice MCQs

Question 1: What type of organism causes dieback disease?
A) Virus
B) Bacteria
C) Fungus
D) Nematode
Correct Answer: C

Question 2: In which region was dieback disease first reported in India?
A) Maharashtra
B) Uttarakhand
C) Andhra Pradesh
D) Kerala
Correct Answer: B

Question 3: What is a significant consequence of dieback disease in trees?
A) Increased water absorption
B) Enhanced fruit production
C) Loss of fruit production
D) Growth of new leaves
Correct Answer: C

Question 4: How does the dieback fungus spread?
A) Through air
B) Through soil and water
C) Via insects
D) By sunlight
Correct Answer: B

Question 5: Which season typically sees the onset of dieback disease symptoms?
A) Summer
B) Winter
C) Rainy season
D) Autumn
Correct Answer: C

Question 6: What is a primary challenge in detecting dieback disease?
A) Lack of symptoms
B) Symptoms mimic drought stress
C) It only affects flowers
D) It spreads too quickly
Correct Answer: B

Question 7: What genus does the dieback fungus belong to?
A) Fusarium
B) Rhizoctonia
C) Phytophthora
D) Trichoderma
Correct Answer: C