Tim Tyler writes
In uk.rec.gardening Oz wrote:
: Tim Tyler writes

:By contrast, the artificial toxins have been designed to be tasteless and
:invisible to consumers.

: One thing I am certain about, and that is that smell and taste features
: absolutely nowhere in anyone's selection procedure for pesticides. The
: infinitesimal residues (if any) left by the time you eat it are only
: detectable (if at all) by hugely sophisticated analytical equipment.

: Just to give you some idea I have visited a site where they could test
: at these levels. They had three areas, with separate doors to the
: outside and staff from each area were not allowed to touch each other
: until their shift had finished. This was because if one of the 'low
: level detection' area walked through the 'high level' area (where the
: test applications were made) then they would totally trash the analysis
: just from particles they picked up walking through.

: As any farmer would tell you, many sprays smell 'rather strongly'.

: So you are quite incorrect.

Reading comprehension problems? Or are you just a troll?

Ahhh, you don;t like being wrong then?

:Strawberries are one of the most pesticide-infected types of produce.
:They don't have natural toxins in.

: I very much doubt that. When I grew them nothing much but the odd slug
: ate them, which is always a giveaway.

I presume you were growing them on your own private planet - where
there are no birds.

Never had a problem with birds, the dogs ate them avidly though.

:They are "designed" to be eaten by mammals like us.

: The fruits maybe. That doesn't mean they aren't toxic. I expect there is
: a fair bit of oxalic acid in them just the same.

The most toxic bit is probably the seeds - but very few of them are
digested.

Maybe, maybe not, but I'll bet there is oxalic acid in them.

:The fungicides sprayed on strawberries are toxic to
:animals like us.

: Fungicides are toxic to fungi.
: That's why they are called fungicides.

Because something is toxic to one kingdom that doesn't mean it
isn't toxic to other ones.

Pretty well everything is toxic at some level, even water, so that's
unimportant.

The question is how big a difference in toxicity is there?
For insecticides it is usually very wide, that's why there is an OP that
kills mites (varoah) but not the bees.

For weedkillers the safety margin is typically very wide, on account of
plants being very different to humans, and for fungi it's much the same.

Of course organic growers are restricted to using nasty heavy metals
(like copper) at high doses to control fungi and these rather
unselective pesticides certainly don't have good safety margins.

Let's take an old fungicide (from the early 80's) propiconazole:
[Because it's one we used a lot]

The full rate was about 250gm/Ha (although like many we saved money by
using half rates) or 25 milligrams/sqm.

A decent crop of wheat will give 800gm /sqm, but most of the spray will
hit the leaves (which is intended) so let's say 8 milligrm hits the ears
(a tad optimistic).

That means we are applying 10mg/kg of wheat.

Now I can't remember if you were allowed to spray wheat in ear with this
product, but let's say you did, and you broke all the regulations and
sprayed just before the combine went in (totally pointless, but makes
the maths easier). Then you get the wheat (just sprayed, remember) and
eat it. How much would you need to reach the no effect level?

Well for dogs the no effect level is 1.9mg/kg bodyweight.
So for a 75kg human that's about 140mg so you would have to eat 14kg of
this wheat daily to reach the no effect level. That's a heck of a lot of
wheat, you couldn't remotely do it. Further you would have to eat all
the husk because the vast majority of the spray (well over 90%) will be
on the husk as it can't reach the grain. If you made it into flour (when
all the outer coats of the grain are also removed) then the level would
be even lower still.

The allowed daily intake (which has safety margins on safety margins,
and why not) is 0.04 mg/kg bw. That's 3mg/day. Even that requires you to
eat all the wheat and husk from 3kg of wheat off this just this minute
sprayed field, I doubt you could do that, either. That's how stunningly
safe fungicides are typically.

Compare that to an organic approved dose of copper oxychloride at about
10kg/Ha (or more). That is it's applied at some 40+ times the dose of
propiconazole. It's so old it doesn't have an ADI or a no effect level
quoted. It is, however, non-biodegradeable, accumulative and very poorly
excreted. The toxic doses are given though.

For the copper: 800mg/kg (LD50) or enough to kill over 100 people/Ha.
Propiconazole: 1517mg/kg (LD50) or enough to kill 1 person/Ha.

but propiconazole is NOT accumulative, IS biodegradeable and IS
excreted, unlike copper oxychloride.

Don't even DARE to look at the organic approved insecticdes. I would
refuse to use them they are so dangerous to the spray operator.

--
Oz
This post is worth absolutely nothing and is probably fallacious.
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