Virginia Commercial Pesticide Applicators CORE Practice Exam

The correct answer highlights that fungi, bacteria, mycoplasma, and viruses together account for a broad spectrum of diseases affecting plants and animals. Each of these pathogens plays a distinctive role in the pathogenesis:

- **Fungi** are known to cause various diseases such as leaf spots, root rot, and blights in plants, as well as contributing to fungal infections in animals. They can thrive in a wide range of environments and often lead to significant agricultural losses.

- **Bacteria** contribute to diseases through various mechanisms, including producing toxins or causing tissue decay. They can affect plants by causing wilts and rots and can also lead to a wide variety of infections in animals, including pneumonia and gastrointestinal diseases.

- **Mycoplasma** are a unique group of bacteria-like organisms that lack a cell wall. They are notable for causing chronic diseases in plants and animals, including certain vascular diseases in plants and respiratory illnesses in animals.

- **Viruses** are significantly important as well; they invade host cells and can disrupt normal cellular functions. Viral infections in plants often result in stunted growth and crop failures, while in animals, they can cause a range of diseases, from mild to severe.

This collective group of pathogens is responsible for