Exam Tips: Plant Diseases and Defenses

Exam Tips: Plant Diseases and Defenses

Key Command Words

• "Name": Give specific examples (rose black spot, TMV)
• "Describe": Give symptoms or characteristics
• "Explain": Give reasons why defenses work or diseases affect growth
• "Compare": Show similarities AND differences between plant and human defenses

Common Mistakes to Avoid

• Confusing physical and chemical defenses
• Forgetting to explain HOW TMV affects photosynthesis
• Not linking environmental conditions to disease spread
• Giving vague symptoms instead of specific examples

Required Practical Links

• Know how to design investigations to test disease treatments
• Understand control variables in field studies
• Be able to identify symptoms and suggest causes
• Link field observations to economic and social impacts

Quick Memory Aids

• Defense types: "Physical-Chemical" — two layers, work together
• Physical defenses: "Waxy-Walls-Bark-Thorns"
• TMV effects: "Mosaic then Less chlorophyll then Poor photosynthesis then Stunted growth"
• Rose black spot: "Spots then Yellow then Drop then Dead"