In 1879, while Mayer held the position of the director of the Agricultural Experiment Station at Wageningen in the Netherlands, he was asked by Dutch farmers to study a peculiar disease affecting the tobacco plant.

At the time, this disease was thought to be spread by very small bacteria or toxins, yet some years later the tobacco mosaic virus (TMV) was shown to be the culprit.

Mayer still concluded that the infectious agent was some sort of bacteria and erroneously claimed that he was able to obtain "clear filtrate" from the infected sap using filter paper in several repetitions.

Filtration experiments with paper and finest porcelain Chamberland filters were replicated by Dmitry Ivanovsky in 1892 and Martinus Beijerinck in 1898, who showed that the infectious agent of the tobacco mosaic disease was in fact infilterable.

Despite the erroneous conclusion, Mayer's pioneer work on the tobacco mosaic disease served as an important step in the discovery of viruses and led to the foundation of the field of virology.