Virginia Commercial Pesticide Applicators CORE Exam

What pathogens are primarily responsible for most plant and animal diseases?

1. Viruses and bacteria

2. Fungi, bacteria, mycoplasma, and viruses

3. Fungi and viruses only

4. Mycoplasma and parasites

The correct answer is: Fungi, bacteria, mycoplasma, and viruses

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