It's a myth. Marigolds are magnets for spider mites. There is only one variety
of marigold which will help manage root knot nematodes.

http://www.ces.ncsu.edu/brunswick/ma...r/mg20515.html


On Sat, 13 Sep 2003 20:30:21 GMT, opined:


I thought Marigolds were so resistant to pests
that one plants them alongside others as deterrent!

Instead, my dwarf Marigolds have been chawed
up; also some Italian Parsley near them. Weird!

Any idea what might be responsible?

TIA