Which type of pathogens are known to cause discolored mosaics on plants?

Viruses are known to cause discolored mosaics on plants primarily because of the way they disrupt normal cellular processes. When a plant is infected with a virus, the viral particles can interfere with the production of chlorophyll, leading to areas of the leaf exhibiting different colors or reduced chlorophyll content. This results in the characteristic mosaic pattern, where patches of light and dark green or yellow areas appear on the leaves. The symptoms vary depending on the specific virus, the plant species, and environmental factors.

In contrast, while bacteria and fungi can also cause various disease symptoms in plants, they typically manifest differently than the classic mosaic patterns linked to viral infections. Bacterial infections might cause wilting, rot, or leaf spots, while fungal infections often produce mold or blight but not the distinct mosaic color changes. Nematodes primarily affect the roots, leading to different stress symptoms but are not associated with leaf mosaic patterns. Thus, viruses are specifically recognized for causing the discolored mosaics seen on infected plants.