tomato plant pests

I have some seedling tomato plants, a few of which are being munched by what I can only describe as tiny, thin, white spiders. They are eating the leaves, and the infected plants I have thrown out. They are in my greenhouse, but I had the same thing last year on older plants that were growing on out doors.Has anyone else had this problem? any suggestions as to get rid of themwould be appreciated

so this year you grow indoor or out doors?

I have them growing in my greenhouse now but plan to put them outside.

Sounds like red spider mite, Gina. If you mist the plants daily to increase humidity, the spiders should move on. More information here

Kate

The red spider mites I come across aren't white. They're also so tiny as to be almost invisible to the naked eye.

Do they look, literally, like spiders? Can you count legs?