On 04/06/2014 13:43, Uncle Peter wrote:
On Wed, 04 Jun 2014 09:45:58 +0100, Martin Brown
wrote:

On 03/06/2014 22:14, ARW wrote:
"Uncle Peter" wrote in message
news

The warning is probably because the houseplants from commercial growers
have been dosed with a persistent systemic pesticide that renders the
plant toxic to sap sucking insects and potentially harmful to humans.

I wish they wouldn't do that. I've got some plants here that produce
tremendous quantities of sap all over their leaves and somehow
splattered onto the window they are next to. I'd appreciate some
insects to eat it.

It is insects tapping the sap that spray honeydew onto your windows.

Anyway, nobody would be stupid enough to think a houseplant was food, so
they don't need the warning.

Citrus plants and bay as below are the most common examples.

You often get bay and citrus trees from garden centres with a warning
not to eat any of the fruit that season. I wonder how many people do?

Everybody I would imagine, nobody reads daft warnings like that. I go
by my stomach and tastebuds.

You can't smell or taste pesticide nerve agents at levels that will
cause you serious harm. They are much more lethal to insects but they
are not something that a sensible person wants to deliberately ingest.
YMMV

If I'm out camping and eat something that
tastes very bitter, I spit it out. If it tastes ok but I get
indigestion afterwards, I don't eat it again (which seldom happens as
most plants that are poisonous also taste bad, to prevent the animal
eating them, rather then just making it ill after the plant's already
lost half it's leaves).

Glycocides for the most part taste like normal sugars but shut down the
cell metabolism when the cyanide gets released. And the most toxic
Amanita fungi of all apparently taste very good indeed but are lethal in
very low doses - I have eaten some of the ones which are edible.

We are lucky in Europe that no indigenous plants have mastered
organofluorine chemistry - the same cannot be said for Australia or
Africa. The things that have eaten fluoroacetate containing plants are
lethal to whatever then tries to eat them and on down the food chain
until it gets diluted. Work is underway to detox it in ruminants.

http://en.wikipedia.org/wiki/Fluoroacetate_dehalogenase

Given that I have seen oleander on sale in supermarkets without adequate
warnings of its very serious toxicity to humans. It is telling that they
warn of skin and eye irritation. I wonder if one of them was a euphorbia
- the sap from them can cause excruciating pain in the eyes.

I'll try to remember not to use it as a tissue then....

It is less forgiving than that. Dry sap on your skin can act as a
photosensitiser or cause really nasty as in hospitalising eye burns.

General rule of thumb is sap runs clear is OK sap is milky latex then
beware (counter example is lettuce which is safe to eat).

I've never seen lettuce sap.

Are you blind as well as dumb?

--
Regards,
Martin Brown