Which group comprises the five major groups of organisms that cause plant diseases?

Which group comprises the five major groups of organisms that cause plant diseases?

• A. Fungi, bacteria, viruses, nematodes, algae
• B. Fungi, bacteria, viruses, nematodes, phytoplasmas
• C. Fungi, bacteria, yeasts, viruses, nematodes
• D. Fungi, bacteria, viruses, mites, nematodes

Answer: (B)

Five broad groups of organisms cause plant diseases: fungi, bacteria, viruses, nematodes, and phytoplasmas. Fungi are a major source of plant disease, causing rots, wilts, blights, and other symptoms. Bacteria produce cankers, leaf spots, and vascular diseases. Viruses disrupt the normal function of plant cells, often spreading through vectors and causing mosaics and stunting. Nematodes are microscopic worms that invade roots and other tissues, interfering with water and nutrient uptake. Phytoplasmas are wall-less, bacteria-like organisms that inhabit the phloem and are transmitted by insect vectors, leading to symptoms such as yellowing and malformed growth. They’re counted as a distinct group because they differ significantly from true bacteria in structure and biology. The other options mix in groups like algae, yeasts, or mites, which aren’t considered one of the five major plant-disease pathogen groups.

Five broad groups of organisms cause plant diseases: fungi, bacteria, viruses, nematodes, and phytoplasmas. Fungi are a major source of plant disease, causing rots, wilts, blights, and other symptoms. Bacteria produce cankers, leaf spots, and vascular diseases. Viruses disrupt the normal function of plant cells, often spreading through vectors and causing mosaics and stunting. Nematodes are microscopic worms that invade roots and other tissues, interfering with water and nutrient uptake. Phytoplasmas are wall-less, bacteria-like organisms that inhabit the phloem and are transmitted by insect vectors, leading to symptoms such as yellowing and malformed growth. They’re counted as a distinct group because they differ significantly from true bacteria in structure and biology. The other options mix in groups like algae, yeasts, or mites, which aren’t considered one of the five major plant-disease pathogen groups.