I wonder how many of these dusts would be considered dangerous by
today's standards? [The advertisement is from 1944]
G'day folks,
Nicotine and Lead Arsenate are the real nasties in those dusts, but I wouldn't be keen on breathing in any of them!
There wasn't much available in the way of respiratory protective gear in those days, either.
But until the advent of the synthetic insecticides post WWII, those chemicals were the only effective means of controlling insects on crops.
All of those which contain Arsenic would now be classed as Schedule 7 [purchase restricted] Poisons. The same class as Strychnine and the Cyanides...
The classification of mixtures containing Nicotine extracts is a bit more complicated; here's an excerpt from the Oz regulatory authority's website.
Schedule 7
NICOTINE except:
a. when included in Schedule 6;
b. in preparations for human therapeutic use; or
c. in tobacco prepared and packed for smoking.
Schedule 6
NICOTINE in preparations containing 3 per cent or less of nicotine when labelled and packed for the treatment of animals.
Schedule 4
NICOTINE in preparations for human therapeutic use except for use as an aid in withdrawal from tobacco smoking in preparations for oromucosal or transdermal use.
https://www.tga.gov.au/book-page/21-nicotineNicotine, and tobacco extracts/dusts, have a long history of use as insecticides - the first recorded use [for control of head lice] is from around 1681!
An interesting, albeit rather technical, article from the RACI journal about the Australian history of its use is at;
http://chemaust.raci.org.au/article/october-2015/nicotine-insecticide-australia-short-history.html