CDFA Pest Prevention Plant Regulation Practice Exam

What type of organism causes chestnut bark disease?

1. Fungus

2. Virus

3. Bacteria

4. Parasite

The correct answer is: Fungus

Chestnut bark disease, also known as chestnut blight, is caused by a fungal organism known as Cryphonectria parasitica. This pathogen infects the bark of chestnut trees, leading to cankers and ultimately contributing to the decline of these trees. The disease was first identified in the early 1900s, and it had devastating effects on American chestnut populations, wiping out billions of trees across the Eastern United States. Fungi, such as Cryphonectria parasitica, have specialized structures that allow them to penetrate plant tissues, reproduce, and spread effectively. The lifecycle and effects of this fungus are well-documented, demonstrating its role in chestnut bark disease. Understanding this relationship highlights the importance of identifying disease-causing organisms correctly, particularly in forestry and plant health management contexts.