Beat the Fungi: Onion Protection Quiz Quiz

Challenge your knowledge of effective disease management in onions with these essential questions. Learn about symptoms, best practices, and control methods to protect your onion crops from common threats.

1. Identifying Downy Mildew in Onions

   Which visible symptom typically indicates a downy mildew infection in onion fields during humid conditions?

   1. D. Yellow wilted roots
   2. B. Circular white spots on bulbs
   3. C. Black streaks along the stems
   4. A. Purple blotches on leaves with fuzzy growth

   Explanation: The hallmark symptom of downy mildew in onions is the presence of pale to purple blotches on leaves, often accompanied by a grayish or purplish fuzzy growth. Circular white spots on bulbs may indicate other fungal issues, black streaks are not typical of downy mildew, and yellow wilted roots usually suggest root rot or nematode damage instead.

2. Crop Rotation for Disease Prevention

   Why is practicing crop rotation important for managing onion diseases like white rot?

   1. B. It increases fertilizer uptake
   2. C. It reduces labor costs
   3. A. It disrupts pathogen life cycles in the soil
   4. D. It produces larger onions

   Explanation: Crop rotation helps break the lifecycle of soil-borne pathogens, like those causing white rot, by depriving them of their preferred host. Increased fertilizer uptake and reduced labor costs are not direct benefits of crop rotation for disease management, and producing larger onions depends on various other cultural factors.

3. Choosing Fungicides Wisely

   When managing Botrytis leaf blight in onions, what should be considered to avoid fungicide resistance?

   1. A. Rotate fungicides with different modes of action
   2. C. Increase application rate each time
   3. B. Always use the same fungicide
   4. D. Apply only before rain

   Explanation: Rotating fungicides with different modes of action reduces the chance that the fungus will develop resistance. Using the same fungicide repeatedly encourages resistance, increasing the application rate can harm crops and the environment, and applying only before rain may not provide effective protection.

4. Sanitation and Onion Disease Management

   How does removing plant debris from fields help control diseases in onion crops?

   1. C. It deters insect pollinators
   2. A. It eliminates sources of overwintering pathogens
   3. B. It raises soil temperature
   4. D. It increases moisture retention

   Explanation: Plant debris can harbor disease-causing organisms over winter, so removing it reduces the risk of future infections. Raising soil temperature, deterring pollinators, and increasing moisture retention are not primary benefits associated with sanitation in disease management.

5. Optimal Irrigation Practice

   What irrigation practice helps minimize foliar diseases like purple blotch in onion crops?

   1. D. Frequent shallow sprinkling
   2. A. Drip irrigation to keep foliage dry
   3. B. Overhead nighttime watering
   4. C. Flooding the fields

   Explanation: Drip irrigation delivers water directly to the soil while keeping leaves dry, reducing the likelihood of foliar diseases such as purple blotch. Overhead watering and frequent sprinkling keep leaves wet, promoting fungal infections. Flooding is not suitable for onions and can cause other problems.