Question: I have about 50 plants in and 6 or 7 of them have a fungus on them. I was looking in here and saw (cucumber mosaic virus) that the only way to get rid of it is to pull them up. I was thinking if there is anything I could put on them to save them.

Answer: I am glad you sent the image because what is effecting your
tomato plants IS NOT A fungus but rather a virus. You have identified
it correctly and there is no cure for a virused plant--it should be
removed.
Gardeners blame everything from vengeful neighbors to dishonest
nurserymen for stunted, non-productive plants that are infected with
viruses. No person is to blame. Thousands of insects such as thrips and
aphids are the culprits that spread viruses. Insects feed on
virus-infected weeds and garden plants, then transmit the virus to
another plant. Not all insects spread viruses. Insects known to cause
problems include aphids, thrips, white flies and leaf-feeding beetles.
Aphids puncture an infected plant with their mouth and draw the virus
particles and cell contents into their body.

Some aphid-borne viruses are carried only on mouth parts but others are
taken into the gut, circulatory system and eventually the salivary
glands. All the aphid has to do is "slobber" on a healthy plant to cause
infection. This is why virus prevention is so difficult -- 100% insect
control is impossible as well as impractical using chemical pesticides.
Even if you could grow a plant that was full of pesticide and would kill
any insect immediately if it damaged the foliage, the virus is delivered
the instant the plant tissue is penetrated. Insect sprays are not the
answer!

Read more about how to protect against virus at:

http://www.plantanswers.com/garden_column/feb03/4.htm