Would need to see a picture of the plants to guess but "white" leaves are usually caused by sun scorch and/or windburn.

But if you put alot on manure in the hole and it was fresh manure, not well composted first, then yes it can kill your plants or at least burn the roots. But there is no way to know if that is the problem without seeing the plants.

OK here is a sad picture of said tomato.

looks like sunburn of said plants. were they hardened off before planting?

I am going to have to google "hardened off" . But I am going to say no, since I don't know what that means.

Thanks terrybull and digdirt. I guess I should have thought to shade them since it is one thousand degrees here. Thanks for the info!

Is there a way salvage these plants?

Sleepy- Give them a bit of shade and leave them be to recover on their own. Then gradually expose them to full sun.

Rodney

Yeah,,, sunburn is the likely cause.
Manure would've had the opposite effect, Dark Green. leaves.

A question : How does the new growth look like ?

Sey