Mosaic Virus in Tomatoes

Mosaic Virus in Tomatoes

One By One

Early in the planting season, I had my tomatoes in the ground and was waiting with anticipation for the first fruits of my beautiful Plants. They got off to a great start and were growing and flowering wonderfully. Then, one day as I went out to turn on the sprinkler and squash any earwigs, I noticed a strange growth pattern on one of my plants. I didn’t think anything of it. A few days later another tomato started doing the same thing. I inspected closer and didn’t get too worried but was confused as to why this had started happening. I hadn’t used any chemicals and it had been a while since I fertilized. Then a few days later, the next tomato started showing the same symptoms. At this point, I figured I better look into this further. What I discovered is that my poor little tomatoes had in fact gotten sick. This was no fungus or an over watering problem, this was something I couldn’t fix. This was Mosaic Virus.

A Virus

As the name indicates Mosaic virus is just that, a virus. It was originally discovered in tobacco plants which is where it gets one of its more popular name Tobacco Mosaic Virus. Unfortunately, this virus can be moved from one plant species to the other. Mosaic virus will overwinter in weeds and other host plants that don’t die completely in the winter.

If Mosaic virus stayed in weeds, that would be great. If an aphid eats a weed that has Mosaic virus then look out. You now have a bug capable of infecting one plant after another moving down the row not covering his mouth when he coughs and making my tomato grow funny.

Early Warnings

The early warning signs are as I mentioned before strange growth patterns. First, you will see the leaves begin to twist as they grow. If you touch the leaf and rub it between your fingers it will feel leathery and the veins and ridges will be very pronounced. Along the leaf stem, there will be small leaf protrusions, another sign of the mosaic virus. Now your plant will continue to grow and produce flowers. However, the growth will be distorted and the fruit it produces will be very bland and meaty.

No Cure

There is no cure for the mosaic virus. It is important to remove the infected material and throw it away. Weed control is very important in controlling mosaic virus, as it will over-winters in weeds. It will wait until next year to begin infecting new hosts. For those of you with open fields nearby you will be extremely challenged in your protecting your plants.


Here are some tips for protecting your prized tomatoes. The primary vector for this disease is aphids and the primary predator of aphids is lady bugs, which you can find at any of your local Zamzows after the first of March. Another trick is to wrap your tomato cages with harvest Guard Fabric when you first plant. This gives you a physical barrier to protect your plants from invaders, and still allows sunlight and water in and protects from frost. Getting a jump on the bugs with an insecticide early on will assure any aphids that land will get killed right away before the get a chance to feed.

I recommend Z-one as this is a very safe insecticide with a low toxicity but does have a residual effect for up to fourteen days depending on the weather.