Cumin Yellowing Challenge Quiz

Explore the causes, symptoms, and management of yellowing disorders affecting cumin crops. Test your agricultural knowledge with focus on common diagnostic and mitigation strategies.

1. Identifying Causes of Yellow Leaves

   A cumin farmer notices widespread yellowing of leaves in his field during the vegetative stage. Which is the most probable primary cause of this symptom?

   1. Alternaria blight
   2. Potassium deficiency
   3. Leaf miner infestation
   4. Waterlogging

   Explanation: Waterlogging deprives roots of oxygen, leading to yellowing due to poor nutrient uptake, which is common in cumin fields with poor drainage. Potassium deficiency can also cause yellowing, but typically appears as marginal browning rather than uniform yellowing. Alternaria blight usually causes spots and necrosis before yellowing. Leaf miner damage is visibly marked by tunnels or patches, not uniform yellowing.

2. Physiological Disorder vs Disease

   If a cumin crop shows yellowing without visible lesions, necrotic spots, or insect signs, but the soil pH was above 8, which type of disorder is most likely responsible?

   1. Thrips damage
   2. Fusarium wilt
   3. Physiological disorder due to alkalinity
   4. Rust disease

   Explanation: High soil pH can cause nutrient deficiencies leading to physiological yellowing. Fusarium wilt and rust cause distinct wilting and pustules, respectively. Thrips damage often appears as silvery streaks, not just uniform yellowing without physical damage.

3. Corrective Action for Cumin Yellowing

   A field of cumin is diagnosed with yellowing due to nitrogen deficiency. What is the most immediate corrective action?

   1. Introduce natural predators
   2. Top-dress with urea
   3. Apply copper sulfate
   4. Spray fungicide

   Explanation: Applying urea supplies nitrogen, addressing deficiency and reducing yellowing. Copper sulfate helps with copper deficiency but not nitrogen. Predators control pests, not nutrient issues. Fungicides have no effect on physiological deficiencies.

4. Distinguishing Cumin Wilt from Yellowing

   How can cumin yellowing caused by Fusarium wilt be distinguished from simple nutrient deficiency?

   1. Uniform yellowing on old leaves only
   2. Presence of black sooty mold
   3. Appearance of powdery white growth
   4. Uneven pattern with wilting and vascular browning

   Explanation: Fusarium wilt causes uneven yellowing along with wilting and internal browning of the stem tissue. Nutrient deficiencies typically show uniform patterns, especially on older leaves. Powdery growth suggests powdery mildew, while black mold is not a symptom of Fusarium or simple nutrient lack.

5. Prevention of Yellowing in Cumin Production

   What is the most effective practice to prevent yellowing disorders in cumin due to water management issues?

   1. Applying extra phosphate fertilizer
   2. Planting at higher density
   3. Ensuring well-drained fields
   4. Increasing the frequency of irrigation

   Explanation: Well-drained soil prevents waterlogging, reducing risk of yellowing. Higher planting density can worsen disease and airflow issues. Extra phosphate helps only with phosphate deficiency, not drainage. Increasing irrigation might worsen waterlogging and associated yellowing.