Coconut Leaf Blight Busters Quiz

Explore key diseases impacting coconut leaves in horticulture, their symptoms, causative agents, and management strategies. Strengthen your understanding of coconut plant health with real-world examples and practical knowledge.

1. Identifying Early Symptoms

   Which of the following is an early visible symptom of coconut leaf blight caused by Helminthosporium species?

   1. Brown ooze from trunk cracks
   2. Yellowing and necrotic spots on older leaves
   3. Massive stem swelling near the base
   4. White cottony growth on young nuts

   Explanation: Yellowing and necrotic spots on older leaves are characteristic of Helminthosporium leaf blight in coconuts, signaling the disease's onset. White cottony growth targets nuts and is typical of fruit rot, not leaf blight. Stem swelling is related to stem bleeding disease, while brown ooze suggests trunk rot or borer infestation, not primarily leaf blight.

2. Causative Agent Recognition

   Which pathogen is most commonly associated with causing leaf blight in coconut palms?

   1. Ganoderma lucidum
   2. Fusarium oxysporum
   3. Helminthosporium spp.
   4. Phytophthora palmivora

   Explanation: Helminthosporium species are primarily responsible for coconut leaf blight. Phytophthora palmivora is mainly associated with bud rot, Ganoderma lucidum causes stem rot, and Fusarium oxysporum is linked to vascular wilt, not leaf blight in coconuts.

3. Disease Spread Scenario

   During the rainy season, a coconut grower observes quick spreading of blighted spots on adjacent trees. What is the most likely mode of spread for the leaf blight?

   1. Insect vector through stem tunneling
   2. Root-to-root contact via soil
   3. Airborne spores and splash dispersal
   4. Seed transmission during planting

   Explanation: Leaf blight pathogens spread mainly via airborne spores and splashing water, especially during rains. Root-to-root spread is typical of soil-borne diseases, insect vectors generally transmit vascular or trunk diseases, and seed transmission is uncommon for leaf blight.

4. Management Strategy Best Practices

   Which practice most effectively reduces the risk and severity of coconut leaf blight in established plantations?

   1. Regular removal and destruction of infected leaflets
   2. Intercropping with susceptible plants
   3. Flood irrigation during summer
   4. Applying high nitrogen fertilizer only

   Explanation: Sanitation by removing and destroying infected leaflets limits the spread of spores and new infections. High nitrogen alone does not target pathogens, flood irrigation may worsen disease spread, and intercropping with susceptible plants can increase overall disease pressure.

5. Differentiating Similar Diseases

   If brown spots on coconut leaves develop concentric rings and worsen during humid conditions, which disease is most likely present?

   1. Red ring disease
   2. Bud rot
   3. Crown choking
   4. Leaf blight

   Explanation: Leaf blight causes brown spots with concentric rings, especially in humid weather. Red ring disease mainly affects vascular tissues and shows yellowing, crown choking restricts leaf emergence, and bud rot affects the growing tip rather than leaf spot patterns.