My wife prides herself on her natural poison-free vegetable garden, but insects were devouring some of her plants, so she sprayed them with Chlorpyrifos. Now she wants me to check the 'Net and find out when these vegetables (squash, gourd, etc.) will be safe to eat. I can Google to find pages like this one, which have a lot of information, but no clear answer to the question.
Reading about Chlorpyrifos is so scary, I suggested that we just never eat those vegetables, but the wife was dissatisfied with that answer. :eek: A point in her favor may be that the poison bottle was several years old, so perhaps had lost much of its potency. :dubious:
Good grief. Talk about going from the sublime to the ridiculous. There are many many steps between “natural poison-free” and “nuke it from orbit”, which is what Chlorpyrifos basically is.
I tend to promote the use of insecticides, but why anyone would choose to treat anything they eat with Chlorpyrifos is beyond me. Next time, try a pyrethroid or nicotinoid. Much safer.
The search term you need to use is “withholding period”. The exact withholding period varies depending on the brand of the pesticide and the crop that you have treated. It will be some time between three days and a month. If you Google the brand, the crop and “withholding period” you should get the information you need. If you don’t know the brand, or the crop doesn’t have a withholding period listed, then don’t eat it.
Well, yeah. The stuff scares me enough to have respect for it. It is a nerve agent after all.
:eek:
OK, that changes things. Do NOT eat the vegetables. Organochlorine concentrates are not chemically stable once exposed to air. Once the container is open, moisture from the air can react with the pesticide producing some pretty nasty breakdown products.
If the pesticide was opened more than ~18 months ago, or if it is past it use by date, then do not use it and don’t eat anything it was applied to. The risk is small, but it’s really not worth it. The breakdown products tend to have LD50s in the *microgram *range. The amount needed to cause permanent organ damage is much less.
My wife is a very simple country girl. It makes her appealing in many ways, but does have disadvantages. She had no idea what poison it was; I decoded it from the “diethyl 3,5,6-tri…” not covered by a store’s sticker. And she presented me (an idiot-savant who would have been little help anyway) with a fait accompli. Please do give her credit for asking the question and insisting I Google for an answer.
I’ll advise her to simply discard the vegetables and the poison bottle (*). She’s not going to like it though … (And, since ignorance and carelessness are rampant where we live, I’m afraid that any market-bought gourds and squash we substitute will be drenched in poisons as bad. :smack: )
(* - “Discard the poison” probably translates as “give to farmer cousin.” :dubious: )
If you are sure it wasn’t opened, and it’s still inside the “Use by” date then you’re good to go. If you can’t find a use by date in the bottle, I wouldn’t risk it.
if a chemical is still good (within its use by date) the disposal could be giving it to someone that will use it following its label instruction (dose, on what kind of plant, where, how, all the details) or take it to a chemical waste disposal facility.
if it is outside of the use by date then take it to a chemical waste disposal facility. most government solid waste agencies (who picks up or where you take your garbage) will have a collection for this; it might be limited to certain days and you need to take it there for consumers to dispose of at no cost.
Preharvest interval is 21 days for Dursban, which is a name brand formulation of chlorpyrifos. But if the formulation was different or applied at a different concentration, PHI could differ. The label should give info about usage, application rates, preharvest interval, etc.
I would consult the recommended application to harvest interval listed on the label, and act accordingly.
Dursban is not something I’d use on vegetable crops, but it isn’t that extreme. Calling it a “nerve agent” doesn’t clarify matters - pyrethin, which is all green and natural is a nerve agent (at least on insects) as well.
And a several year old bottle of Dursban, unless way past the expiration date is not liable to have mutated into nuclear waste. Let’s get a grip here.
No, the period varies depending upon the crop and the aplication. Crops with waxy or acid cuticles may require up to a month. Other crops as little as 3 days.
It’s about the most toxic OTC pesticide you can get. Not sure how much more extreme you can get
IOW unless you are a giant insect, not a nerve agent.
There is no way that it can mutate to nuclear waste regardless. How likely it is to have broken down into highly toxic substances is something that, last I heard, even the experts had no idea of.
But since you seem to have some idea of what the risk is, can we have a reference?
Good idea. Let’s see some facts to support your claims of what the risks are.
Don’t be so sure of that. While pyrethrin is generally regarded as safe to use, it can cause people trouble via overexposure.
“Effect on human health…On broken skin, pyrethrum produces irritation and sensitization, which is further aggravated by sun exposure. Absorption of pyrethrum through the stomach and intestines and through the skin is slow. However, humans can absorb pyrethrum more quickly through the lungs during respiration. Response appears to depend on the pyrethrum compound used. Inhaling high levels of pyrethrum may bring about asthmatic breathing, sneezing, nasal stuffiness, headache, nausea, lack of coordination, tremors, convulsions, facial flushing and swelling, and burning and itching sensations (Extoxnet 1994).”
Lack of coordination, tremors and convulsions suggests neurotoxicity in humans. Bugs are obviously far more susceptible to the product but we’re not immune.
You made the claim. I expressed doubt that there would be significant risk to using several year-old Dursban on food crops based on “nasty breakdown products”. If you have evidence that this is so, kindly present it (if the experts have no idea, your presenting risk as a given sounds pretty shaky).
I’ll summarize what my wife has decided. Although irrelevant to my original question, I should have added context by mentioning that we live in Thailand.
We won’t eat the current crop of okra and string beans – just use their seeds. The other vegetables won’t be ripe until their withholding finishes anyway.
When my wife mentioned to relatives and friends that she might discard vegetables due to poison concern, the universal reaction was “No! give them to me.” Anyway, as my wife points out, any vegetables we buy in local markets are likely to be more poisoned than anything from her garden. :mad: :smack:
Anyway, as my wife points out, any vegetables we buy in local markets are likely to be more poisoned than anything from her garden. :mad: :smack: