Martinus Beijerinck

March 16, 1851
And today is the birthday of the Dutch microbiologist and botanist Martinus Beijerinck ("By-a-rink”).

Now Martinus was a very smart man - a very brilliant botanist - and he was searching for the reason that tobacco plants were dying. And to do his research, Martin ground up some diseased tobacco leaves, and then he pressed the juices through a bacteria filter.

And you can imagine his surprise when the filtered, bacteria-free liquid still spread the disease. It was only after reviewing his experiment that Martinus correctly deduced that a microorganism smaller than a bacteria was causing the problem, and he called this very little thing a virus, which is the Latin word for poison.
Now before 2019, two of the most common viruses in humans were the flu and the common cold. But today, of course, there's only one virus on all of our minds, and that is the Coronavirus or COVID 19.

But, you know, plants suffer from viruses as well. And here's a top 10 list voted on by plant virologists associated with molecular plant pathology:

1. Tobacco mosaic virus (TMV)
2. Tomato spotted wilt virus (TSWV)       
3. Tomato yellow leaf curl virus (TYLCV)       
4. Cucumber mosaic virus (CMV
5. Potato virus Y (PVY)
6. Cauliflower mosaic virus (CaMV)       
7. African cassava mosaic virus (ACMV)
8. Plum pox virus (PPV)       
9. Brome mosaic virus (BMV)       
10. Potato virus X (PVX)