Like Smeghead,
I’m fighting a wasp problem. I’ve had good luck with pyrethrin-based wasp sprays. The wasps never leave the nests; they just convulse and fall off dead.
Now, pyrethrins are made from chrysanthemums, right? Furthermore, I believe that, while they are deadly to insects, they are only somewhat harmful to humans. Why? Do they work to destroy the exoskeleton like boric acid does, but faster, or is there some other mechanism at work?
Also, how harmful are pyrethrins to humans, and could I plant chrysanthemums near where the wasps nest to keep the wasps away?
From what I was able to deduce from http://pmep.cce.cornell.edu/profiles/extoxnet/pyrethrins-ziram/pyrethrins-ext.html it seems that pyrethrins aren’t even amazingly toxic to insects except that you’re overdosing them. If you give an insect a moderate dose, it will be stunned but will quickly overcome the poison and break it down. The amount of pyrethrins in insect sprays isn’t enough to harm a mammal due to its larger size, but given a big enough dose, you can cause symptoms in humans that suggest nerve damage (which is how it kills insects).
Botanical insecticides are naturally-derived insect toxins from plants. Several such chemicals have been formulated for insect management in the home garden.
Botancial insecticides tend to break down rapidly in the environment and are less toxic to mammals than traditional, synthetic insecticides. They are broad
spectrum insecticides and will harm beneficial insects. Many are also harmful to fish or other wildlife. Whether using synthetic or botanical insecticides, all
insecticides are designed to kill insects. They must be used according to the label. A common botanical insecticide, Pyrethrum, is derived from the dried flowers of
Chrysanthemum species grown in Kenya and Ecuador. It is available in dusts and sprays. Pyrethrum is a contact poison labelled to control ants, aphids, roaches,
fleas, and ticks. It degrades rapidly and is non-toxic to most mammals.
I went looking because I can remember hearing cases of fish dying when there have been chrysanthemum leaves in the pond & wasn’t sure if it had been exaggerated/blamed on wrong thing. Many sites list chrysanthemum as causing dermatitis/red rashes on contact with leaf/stem, but have no mention of what would happen if an animal was foolish enough to eat it…but it doesn’t sound very effective for keeping wasps away & I am sure that we have had white fly eating our chrysanths before now, so it doesn’t sound like it is very concentrated!
I did a search on:
chrysanthemum +toxic
& turned up a lot of links for pet health (avoiding planting poisonous plants) pages…but not much detail.
Fi.
Normally I’d say that what I’m about to add isn’t substantive enough to post, but this thread isn’t exactly rollin’ along like gang-busters, so I’ll throw it into the pot:
In the musical Pacific Overtures (a GREAT score, BTW) there’s a scene containing a song called “Chrysanthemum Tea” sung between the Japanese Shogun and his mother. The conclusion of the song has the Shogun dying of the poisoned tea his mother offered him at the beginning of the song. (FYI: It was no accident… mom offed him on purpose!)
True, there is no implication that CT is inherently poisonous, but the show is “based” on non-fiction events. Stephen Sondheim, who wrote the score, seldom gets his details wrong… and as a man whose passion for murder mysteries is renown (the game-loving character in “Sleuth” was partly based on him) he would know about innocuous-seeming poisons.
(Quasi-hijack here: Another Pacific Overtures song holds a clue to a different SDMB question, namely Milk and Tea. In the song “Bowler Hat,” the Japanese ambassador recites the lessons he’s learned from Western culture. He sings “…you pour the milk before the tea…”)
See, and you thought all you could learn from show tunes is who’s gay!
Unfortunately, some of the sites I got when searching on Chrysanthemums seemed to be fromhomeopathic sites saying how good for you it is - antibiotic properties, eyewash etc. Now we all know the great man’s opinion of homeopathy, butI don’t think they’d be allowed to sell something toxic (sun burnt red? have some cyanide, it’s great for your complexion…) - of course, I could be wrong as drugs companies have got away with all sorts of things before (often out of ignorance at the time).
Fi.