Viral mosaic diseases are characterized by the appearance of alternating spots of different colors on plant organs, including light rings, star-shaped spots, or stripes. In addition to specific variegated coloration, affected plants often exhibit leaf blade curling, wrinkling, and crinkling, as well as stunted overall growth and deformation of fruits and flowers. Sometimes the infection is latent, where visual symptoms are absent, yet crop productivity is significantly reduced.
Pathogen dissemination occurs through vectors such as aphids, true bugs, mites, and nematodes, as well as through mechanical transfer of sap from diseased plants during care, pruning, or physical contact. Infection is possible via seeds, planting material, soil, and crop residues. The intensity of infection development depends on weather conditions, particularly temperature regimes, and crop density, which facilitates rapid virus transmission.
Varietal resistance to mosaics is determined by the presence of specific or recessive genes affecting translation initiation. During breeding and variety testing, resistance is evaluated under artificial inoculation on infectious disease plots. Modern diagnostics for controlling viral load include enzyme-linked immunosorbent assay (ELISA) and polymerase chain reaction (PCR), while field resistance is determined by a variety's ability to not accumulate the pathogen throughout the growing season.