It does not look like Mosaic because it is not a pattern, its more of a solid yellow with some green. I am hoping its a fungal, but it's probably Rose Mosaic Virus from hybrid tea plants. Normally I take them off, and there are not a lot of them, and if I use fungicides the issue improves.

That does not look like RMV at all. My thought was some type of insect damage. RMV is usually very yellow and the leaves stay supple until they drop and not dry brown looking like that. Spray burn can also cause dry brown spots like that. It could also be caused by weather conditions if you've had storms or extremes.

Unless you have your rose tested, you cannot tell which virus (or viruses) your rose has. One of the more common viruses is aphid spread (and it is apparently widely prevelant in California). https://sites.google.com/site/rosespringdwarf/home -------------------------------------------------------------------------------------- For descriptions of the known rose viruses please see: https://sites.google.com/site/rosevirusindexpage/

What temperature zone are you in? Roses have an immune system that is more effective against some of the common rose viruses at high temperatures. Without knowing where you live and which actual virus (or viruses) your plant has (plus which strain you have, strong or weak), one cannot predict whether your infection is simply a cosmetic problem or could affect your plants growth and longevity and possible spread to your other roses. This is the most recent paper that I could find (see page 17 about roses in Table 1): https://apsjournals.apsnet.org/doi/pdf/10.1094/PDIS-05-20-1061-FE The affiliations of the authors in the above paper are: Authors and Affiliations M. Fuchs † , School of Integrative Plant Science, Cornell University, Geneva, NY 14456 C. V. Almeyda , Micropropagation and Repository Unit, North Carolina State University, Raleigh, NC 27695 M. Al Rwahnih , Foundation Plant Services, Plant Pathology Department, University of California, Davis, CA 95616 S. S. Atallah , Department of Agricultural and Consumer Economics, University of Illinois, Urbana-Champaign, IL 61820 E. J. Cieniewicz , Plant and Environmental Sciences, Clemson University, Clemson, SC 29634 K. Farrar , Foundation Plant Services, Plant Pathology Department, University of California, Davis, CA 95616 W. R. Foote , Crops and Soil Sciences, North Carolina State University, Raleigh, NC 27695 D. A. Golino , Foundation Plant Services, Plant Pathology Department, University of California, Davis, CA 95616 M. I. Gómez , Charles H. Dyson School of Applied Economics and Management, Cornell University, Ithaca, NY 14853 S. J. Harper , Department of Plant Pathology, Washington State University, Prosser, WA 99350 M. K. Kelly , Department of Agriculture and Markets, Division of Plant Industry, Albany, NY 12205 R. R. Martin , Department of Botany and Plant Pathology, Oregon State University, Corvallis, OR 97331 T. Martinson , School of Integrative Plant Science, Cornell University, Geneva, NY 14456 F. M. Osman , Foundation Plant Services, Plant Pathology Department, University of California, Davis, CA 95616 K. Park , Charles H. Dyson School of Applied Economics and Management, Cornell University, Ithaca, NY 14853 V. Scharlau , Washington Wine Industry Foundation, Cashmere, WA 98815 R. Smith , University of California, Cooperative Extension, Sonoma County, Santa Rosa, CA 95403-2894 I. E. Tzanetakis , Department of Entomology and Plant Pathology, Division of Agriculture, University of Arkansas, Fayetteville, AR 72701 G. Vidalakis , Department of Microbiology & Plant Pathology, University of California, Riverside, CA 92521 R. Welliver , The Pennsylvania Department of Agriculture, Bureau of Plant Industry, Harrisburg, PA 17110 ----------------------------------------------------------------------- The following is a more complete discussion of the temperature effect (which applies to some of the rose viruses): https://sites.google.com/site/temperatureandrosemosaicvirus/home