Defending Apples: Canker Control Quiz Quiz

Explore effective apple canker management with this horticulture quiz, covering disease identification, prevention, and control strategies for healthy orchards.

1. Identifying Pathogens

   Which fungal pathogen is most commonly associated with apple canker in temperate regions, often causing sunken lesions on branches and trunks?

   1. Venturia inaequalis
   2. Neonectria ditissima
   3. Pythium ultimum
   4. Fusarium oxysporum

   Explanation: Neonectria ditissima is the primary cause of apple canker in many regions, marked by characteristic sunken lesions. Venturia inaequalis causes apple scab, not canker. Pythium ultimum is involved in root rot diseases. Fusarium oxysporum is mainly a wilt pathogen affecting other crops but not apples.

2. Cultural Management Practice

   What is the most recommended time to prune apple trees to reduce canker risk, and why?

   1. During dry weather in late summer
   2. Mid-winter during frost
   3. Late autumn before leaf fall
   4. Early spring after significant rainfall

   Explanation: Pruning during dry weather in late summer minimizes infection risk as spores are less prevalent and wounds heal faster. Pruning after rainfall increases moisture and canker spread risk. Pruning in mid-winter can slow healing due to cold, and late autumn pruning leaves wounds exposed to spores during damp conditions.

3. Chemical Control Choice

   Which chemical method is often integrated into apple canker management programs, particularly during the dormant season?

   1. Glyphosate herbicide treatments
   2. Use of neonicotinoid insecticides
   3. Foliar nitrogen sprays
   4. Applications of copper-based fungicides

   Explanation: Copper-based fungicides are commonly applied during dormancy to help control canker pathogens. Neonicotinoids target insect pests, not fungi. Nitrogen sprays promote foliage growth but don't control cankers. Glyphosate is an herbicide, unsuitable for fungal disease management.

4. Resistant Varieties

   Why are certain apple cultivars selected to reduce canker problems in orchards?

   1. They produce more fruit per branch
   2. They tolerate lower soil fertility
   3. They have larger leaves for shade
   4. They offer increased resistance to Neonectria infection

   Explanation: Cultivars are chosen for canker management based on their resistance to Neonectria infection, limiting the severity and spread of disease. Increased fruit yield, larger leaves, and soil fertility tolerance do not directly reduce canker issues.

5. Sanitation Practices

   What is the main purpose of removing and destroying infected branches from apple trees as part of canker management?

   1. To reduce sources of fungal spores for future infections
   2. To increase sunlight into the canopy only
   3. To conserve soil moisture
   4. To promote earlier fruit ripening

   Explanation: Removing infected branches eliminates fungal spore sources, lowering the risk of new canker infections. Increasing sunlight, promoting fruit ripening, and conserving soil moisture do not address canker pathogen spread.