Little Bitty Dusters for applying fungicide

Rodger Whitlock
Sun, 22 Dec 2013 09:55:19 PST
On 21 Dec 2013, at 17:34, Robin Hansen quoted Diane Whitehead:

> "The only fungicide I use is powdered sulphur.  I take a pinch between thumb and
> finger and slide them together so it dusts down."
> So, Diane, sulfur used the way you use it (with gloves? without gloves, mask,
> etc.?) is non-toxic to humans?

Sulfur is fine. It is, in fact, an essential nutrient.

Speaking as a trained chemist.

It endlessly annoys me that the hysterics these days run around "it's a 
chemical, it's a chemical" or "it's poisonous, it's poisonous" with no sense of 
understanding or nuance and end up frightened by things that can't harm you or 
won't harm you much.

Chemicals: almost everything is a chemical: water, salt, and sugar, for 
example. Atmospheric oxygen, too. If you work a little harder you can say "it's 
a synthetic, petrochemical-derived pesticide with a high mammalian LD50, no 
thanks" and then you'll be much closer to a reasonable attitude. Insecticides 
were chosen for marketing partly on the grounds that they had a high LD50 for 
insects relative to their LD50 for mammals, and the ratios of the two LD50 
figures is sometimes quite astonishing. That said, I'd still be cautious with 
the old classic pesticides: captan, benomyl, methoxychlor, diazinon, and 
malathion. (Many of these are now verboten in many places.)

By way of contrast, Sevin (carbaryl), a cholinesterase inhibitor, has such low 
mammalian toxicity that it can be used as a flea powder on cats. Makes them 
drool a little, but that's all. It is extremely toxic to hymenopterous insects 
(bees, ants, wasps) so it's good for dusting hornet nests, but very bad used on 
flowering plants where bees are foraging.

But *reasonable* care is always a good idea. I wouldn't use any of these 
synthetic, petrochemical-derived insecticides without putting on gloves. The 
pale blue nitrile rubber gloves used by mechanics are good (and won't cause 
latex sensitivity), so make sure your gardening supplies include a box.

I don't know enough about the much more modern neonicotinoid insecticides to 
pontificate on them, but they have been implicated in bee colony deaths. I only 
use them on my cats on the rare occasions they get fleas.

As for "poisonous! poisonous! quick, run, hide, everyone", the difficulty is 
lack of nuance. There are some plants you're crazy to grow; the director of Kew 
Gardens, for example, wouldn't have Aconitum ferox in his garden. It's 
extremely poisonous — lethal, in fact — and can kill you. (If you grow root 
crops, do NOT grow any aconitum species: people have died from thinking their 
tubers are Jerusalem artichokes.)

On the other, those lists of "100 common poisonous garden plants" you see in 
magazines and newspapers (what are those? says the e-generation) are too 
tainted by modern journalism's love of sensationalism to be trusted. Yes, 
daffodils are in some sense poisonous, but I suspect that all you get is 
diarrhea and an upset stomach.

And of course, if you have a yard ape or rug rat on the premises who tends to 
mouth anything he or she sees, daphnes are probably a bad idea: their berries 
(many bright red) may attract said yard ape's (or rug rat's) attention.

Nuance, people, nuance. Don't think in broad categories or you'll end up 
cowering in fear in a basement corner. But also don't be a fool and think 
"everything is quite innocuous".

End of today's Sunday sermon. Send money.

Rodger Whitlock
Victoria, British Columbia, Canada
Z. 7-8, cool Mediterranean climate

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