Those are aphids. You could use organic insecticidal soap sprays from the big box stores if you want.

aphids if left alone to multiply can harm the plant because they are little plant vampires that suck the juices of the plant.

This post was edited by Erich_k on Mon, Jun 3, 13 at 12:12

Thanks so much for the response.

There are about 5 tomato plants and only one of them has these. Should I be spraying all of them.

Also should I spray the underside of the leaves ?

Regards
G

yeah insecticidal soap is a contact killer so you should spray the undersides of the leaves where they like to gather.

Just repeat every week if you see them. If left unchecked they will stunt the growth of the plant i lost a cutting or two from outside to them because i was not careful enough to make sure no aphids got inside.

another if not icky way to rid of them is either rub them off with your fingers though this will not work as well if they are hiding in small crevices like the tomato blossoms and the like

Neem oil worked for me last year. I had tons of them. Spray every square inch of the plant.

Thanks a lot for the suggestions. I will try to first flush it off with a gentle jet of water ... then if they persist try the hand method... then the soap water ... then the garlic ... then the neem :)

Didnt know this was so common on the forum. Thanks so much !
G