Latent mosaic of potato
Some strains of potato virus X produce no visible symptoms of latent mosaic, although yields may be reduced 15% or more when compared to virus-free plants. Other strains cause a mild mosaic with slight leaf crinkling under periods of low light intensity and low temperature (60? to 68?F). The additional presence of potato virus A or Y may cause crinkling, rugose mosaic, or browning of leaf tissue.