Battling Powdery Mildew in Cowpea Quiz

Explore key facts about powdery mildew in cowpea crops, covering symptoms, prevention, and effective responses for sustainable agriculture. This quiz provides medium-level questions for practical awareness among cowpea growers.

1. Identifying Initial Symptoms

   What is a common early symptom of powdery mildew infection on cowpea leaves?

   1. Yellowing between major leaf veins
   2. Leaf edges turning brown and curling
   3. Black, sunken lesions at the stem base
   4. White, powdery spots on the leaf surface

   Explanation: Powdery mildew typically presents as white, powdery spots on the upper surfaces of leaves, which can later spread. Yellowing between veins and brown curling edges are more indicative of nutrient issues or other diseases like bacterial blight. Black, sunken lesions generally signal stem or root rot, not powdery mildew.

2. Environmental Conditions Favoring Disease

   Under which environmental condition does powdery mildew most commonly develop on cowpeas?

   1. Extended periods of drought with strong sunlight
   2. Warm days with high humidity and cool nights
   3. Heavy, prolonged rainfall
   4. Consistently low soil moisture

   Explanation: Powdery mildew thrives in environments with high humidity and moderate temperatures, especially when warm days are followed by cool nights. Heavy rainfall often discourages the disease by washing away spores, while drought or low soil moisture is more related to wilting, not fungal growth.

3. Best Cultural Practice for Prevention

   Which cultural practice best helps prevent powdery mildew outbreaks in cowpea fields?

   1. Planting cowpea in shaded areas
   2. Using shallow irrigation to avoid wetting foliage
   3. Applying excessive nitrogen fertilizer
   4. Increasing spacing between plants for better airflow

   Explanation: Improving airflow by increasing plant spacing helps leaves dry quickly and reduces fungal growth. Shallow irrigation does not directly prevent mildew, and excessive nitrogen can promote lush, disease-prone growth. Shaded areas may increase humidity, inadvertently encouraging mildew.

4. Common Misidentification

   What disease is most commonly mistaken for powdery mildew on cowpea due to similar visual symptoms?

   1. Rust
   2. Anthracnose
   3. Downy mildew
   4. Root knot nematode

   Explanation: Downy mildew can cause pale or fuzzy spots and is often confused with powdery mildew, but the fungi and management differ. Rust produces yellow to orange spots, root knot nematode causes root galls, and anthracnose shows as dark lesions on stems or pods.

5. Preferred Control Method

   What is a recommended sustainable method for controlling powdery mildew in cowpea crops?

   1. Frequent overhead irrigation
   2. Spraying copper-based bactericides
   3. Applying large amounts of urea fertilizer
   4. Growing resistant cowpea varieties

   Explanation: Using resistant varieties is sustainable and helps reduce disease pressure. Excessive urea and overhead irrigation can worsen fungal problems. Copper-based bactericides are more suited for bacterial diseases rather than fungal ones like powdery mildew.