Definition
A scorch is any symptom that suggests the action of flame or fire on the affected part, often seen at the margins of leaves.
Discussion
Common factors associated with leaf scorch or causing leaf scorch:
1. Root rot, which reduces the plant's ability to uptake water, causing the most distal foliar tissues such as leaf margins to to dry out first
2. Vascular diseases that clog up or block the xylem elements from transporting sufficient water to leaves
3. Pesticide injury
4. Drought
5. Fertilizer burn
6. Nutritional deficiences (e.g., potassium, magnesium)