I read the article that Dice linked to and I agree with some of the controls and not others.
When you first see the beetles/damage go thru your tomato plants and try to remove them by hand. They have this nasty habit of playing dead and dropping from the plant so beware of that. It mnight be best to use a can with kerosene in it or whatever, and try to tap them into the can before the play dead and fall off.
Then look for the clusters of orange eggs on the backs of leaves, take off those leaves and stomp on them. QED.
While lots of critter controls were mentioned in that article I honestly don't know of anyone who has tried them and given any feedback.
If you have too many plants to groom manually then I suggest that you ASAP get the BT product referred to in the article, often soild as Colorado Potato Beetle Beater ( cute, eh?) b'c that will kill the emerging larvae which are the form of the beetle that does the most damage.
And 5% Rotenone usually kills the adult beetles, but note that's 5%, not the common 2% that's usually sold.
You sepcifically asked about the larvae and I can tell you that the BT product WILL kill them; they ingest it, the Xstals in the BT poke holes in their guts and they blow up, if you want me to be specific.
