NMoasis said: this is magical thinking.
I did a search...
https://ask2.extension.org/kb/...
According to extension, casoron is a class III acute toxicity pesticide and is considered a possible human carcinogen.
Not really anything I'd want in my garden...
Apparently the poison is used as a pre-emergent herbicide... preventing seeds from germinating, but doesn't kill growing plants.
So... I guess that you'd be taking your chances... The tomatoes shouldn't be killed by this stuff... but whether you would feel safe eating them... whole nother question.
Time to send the landscape crew packing... Nobody needs a "perfect" stand of turf... We all need safe food.
