[40four]

Glyphosate is the main ingredient in "Round up". I imagine residential use probably has a minimal impact, but this seems like a big problem considering the rise of "Round up resistant" crops. When whole fields are being sprayed at scale, seems like that could be very disruptive to a bee population.

[bryanlarsen]

Actually, it's quite possible that residential use is much more harmful than agricultural usage. The study used very high concentrations of glyphosate, and residential usage of glyphosate uses it at a much higher concentration than farmers do.

[chicob]

I was about to say that.

From a personal experience (I'm a farmer) the concentrations used in a residential context are exaggeratedly above the recommendation. They are mismeasured and generally high.

Plus, glyphosate preparations need to be corrected in pH (below 5 for maximal efficacy), which is something many people don't do.

The professionals doing weed control in cities absolutely must have training and adequate PPE. The same thing applies to pest control.

I'm not against professional usage of pesticides, but I would be OK with forbidding most insecticides and herbicides for personal usage. The every day insecticide spraying can? That thing is poison. Does anyone use a FFP2 mask or even a simple cotton mask? Many permetrine-based insecticides don't even mention that this active substance is specially deadly to cats.

[Karunamon]

>I'm not against professional usage of pesticides, but I would be OK with forbidding most insecticides and herbicides for personal usage

That is entirely unreasonable as a conclusion. It leads to a world where only people rich enough to hire landscapers and exterminators are able to control insects and weeds.

Of course insecticide is poison. That's literally the point. Don't breathe it, get it on you, or let your pets around it. It's not difficult advice to abide by.

[klmr]

You make a good point but I wouldn’t banning a potentially dangerous chemical that requires expert use to be safe “entirely unreasonable”. In fact the same is true for most such compounds, at least in large parts of Western Europe (less so in the US, I think, but something as harmless as Sudafed is a counter-example): there are many industrial chemicals which you cannot (or only via detours) purchase legally in stores.

I’m generally not a fan of such regulations because most of these chemicals have no common use and the potential for abuse is therefore relatively small. But for many pesticides and herbicides, the potential for harmful misuse is very real.

[chicob]

I usually can find several consumer-grade insecticides that make no mention of the active substances they contain, the health risks, and security or no-entry intervals.

If informed professionals need this information, won't lay people need it as well?

[chicob]

Also, sometimes I don't understand the downvotes. This baffles me. Your comment is perfectly reasonable, and so is the comment you were replying to, even if one doesn't agree with it.

[chicob]

Just as a reference, the last time I used glyphosate the concentration was 15 L of concentrate (glyphosate 360 g/L) to 1000 L water. This is equivalent to 5,4 g/L. The study mentions two concentrations, 10 g/L and 5 g/L, so I think this is representative. Generally I would use more glyphosate, but now I usually mix it with oxyfluorfen in order to cope with glyphosate resistance and use less of each.

[bryanlarsen]

Representative if the bees are drinking straight from your sprayer, for multiple days in a row.

[chicob]

Actually, it's the other way around. My bad.

I misread the paper: it says 5 mg/L and 10 mg/L, which is a thousand times less concentrated than the prepared spray. At any rate, this is the environmental dosage the bees come in contact with, not the sprayer's concentration.

So I searched for the basis for those targets of 5 mg/L and 10 mg/L.

The article reads:

"Glyphosate concentrations were chosen to mimic environmental levels, which typically range between 1.4 and 7.6 mg/L".[original article]

The reference for this interval[1] makes reference to three other papers. One of these (from 1988) makes reference to another study on the "effects of a 2.2 L/ha Roundup application".[2] Another, from 1990, mentions an analysis of water residues "following application of ROUNDUP (2.0 kg/ha)"[3].

I have no idea what residues I'd find in my property, but the recommended dosage of concentrated product is still 2-4 L/ha. I am currently doing 3 L/ha.

Different brands of glyphosate concentrate usually have the same concentration, but this value might have changed after 30 years.

[1] http://jeb.biologists.org/content/217/19/3457?ijkey=7c53a3bc...

[2] https://link.springer.com/article/10.1007%2FBF01705439

[3] https://pubs.acs.org/doi/pdf/10.1021/jf00094a045