On Mar 31, 4:46 pm, Jangchub wrote:
On Sat, 31 Mar 2007 19:22:57 +0100, Janet Baraclough

wrote:
Marigolds are a member of the family which are the natural source of
pyrethrum, which was marketed as an effective insecticide. The pungent
smell-quotient in marigold leaves, is the pyrethrum, so ones with the
smelliest leaves, have the most insecticide.

In the UK, gardeners who grow tomatoes and basil in glasshouses,
often grow marigolds in there too, as a sacrifice plant to kill
whitefly.

Janet.

Wrong. C. coccineum is NO relation to Tagetes. You are also wrong
about it being the "leaves, is the pyrethrum." Pyrethrum come from a
Chrysanthamum coccineum plant and it is the crushed flowers where the
poison is, not the foliage.

Yes, and marigolds are used as companion plants with tomatoes, and
they do not contain pyrethrum.
The main point is that they deter certain insects that like tomatoe
plants.
Marigolds are not an insecticide. They are a deterrent.

dancing in my mind,
gloria in hemlock hollow
(only the iguanas know for sure)