Pesticide start up. Is this all I need?

Than you Appleseed for a very comprehensive explanation! Just several more important points.

Most formulations of Captan have a zero day PHI for most crops but also a 24 hour REI ( most crops). It can cause irreversible eye damage.

Imidan has a 4-7 day REI, but 14 days for public entry on a U-pick farm. Its use is also prohibited in a public park or recreation setting. Not sure why these restrictions exist for Imidan, they don’t for most farm chemicals I’m familiar with.

Most accidents occur during mixing, before the chemicals are diluted with water.

A full face respirator and a spray suite are not required, but I use them when I spray farm chemicals.

Do yourself a small favor and learn the simple math required to spray right. Might save your life.

Meaning the dilutions?

Yup, not picking on you, every one needs that message. You started a great thread and you got great info from the absolute best guys and girls in the nation IMHO. One other piece of advise from a oldtimer who has sprayed and sold chemicals for 35+ yrs., Every time, every chemical, read and follow the label instructions. Soap box is done, thanks.


Yeah…Olpea learned me up on the blindness thing a while back so it gets the warning, or caution label (whichever is worse, I forget). I looked up some health risks associated with different chemicals last night and there are many that can cause blindness…I didn’t know that either.

Blueberry, I’m unclear on how you could, on one hand have a 24 hour entry restriction while at the same time having a zero PHI. How could one harvest without entering?
Since we were initially talking about apples, lets just say for apples the PHI is zero.

GOOD POINT! This is one of the downsides to spraying stronger commercial pesticides in the home orchard and I should have mentioned it. I actually thought the reentry period for Phosmet was even longer, but I think I remember you correcting me on that before. I was relieved at the shorter PHI.
I suspect it’s linkages to ADHD has a lot to do with increased reentry and so forth.
It also should be noted that the most used pesticides garner the most regulatory attention. Imidan was (and probably still is) the most widely applied pesticide in the world, so naturally it gets more attention. In addition to that, it being an organophosphate draws further scrutiny and scorn from the EPA.
In other words, Imidan probably has the biggest book on it as compared with other insecticides, at least the more modern ones. I believe Imidan was introduced in the late 60’s.
BTW, I know you know all this, I’m stating it mostly for the benefit of others.

Another BAD thing about Imidan is the odor which most here are already aware of. It stinks to high Hell. From the moment you open the package you know beyond all doubt this is no OTC product from walmart or lowe’s.

In Rally’s case his orchard is at his camp in the woods (if my memory serves me, which it may not), so he should be fine with it.
Imidan has restrictions of spraying within so many feet of buildings and dwellings too. That’s why I said “for those who have the space for it”.
cckw: I personally would not allow any pets I was affectionate towards in any spray area, regardless of the spray materials…everything save for Carbaryl (Sevin). I only say that because until 15 years or so ago, Sevin was actually listed and labeled for use on pets for flea and tick control, which it was very good at. I’ve personally used it and ticks dropped off the pup like peppercorns being shaken from it’s fur.

Someone here (I forget who…Brady maybe) posted a chart listing human health issues related to different pesticides. Imidan surprisingly scored quite well in comparison with it’s peers. The long and widespread use of it may offer some level of assurance also…maybe, maybe not.
There really aren’t any super safe and effective pesticides

I have asked the same question and never received a good answer, but that is what the label says! If the PHI is zero but the REI is 48 hours, how go you enter the field to harvest the fruit with a zero PHI? I wish I had a better understanding of the chemistry involved as well as the rules that determine the label requirements.

Also the PHI for some chemicals change a huge amount from crop to crop. Take Mustang Max (a permethrin) for example - 14 day PHI on apples, but only 1 day on blackberry.

I know the EPA is trying to reduce the use of OP like Imidan or Lorsban, but most of the “safer” neo-nics are real hard on bees and many beneficial bugs. Like you indicated, nothing is super safe.

Imidacloprid and Permethrins are also pretty safe for pets, at least so safe that you can directly apply them on your dog (K9 Advantix).

Yes, and I believe Gamma Cyhalothrin is still used as a flea and tick dip, and in extraordinarily high concentrations too, I think close to 10% which would be magnitudes greater (around 1,000 times?) than a product like Once and Done.
It is most definitely NOT safe for contact with human skin though.

The issue isn’t just the contact though. As one poster here pointed out, his dog liked to eat grass. So ingestion (potentially quite high levels) becomes a real concern. None of these chemicals including imidacloprid are safe in that regard. Carbaryl on the other hand actually is, believe it or not. It takes quite high ingestion levels of Carbaryl to be an issue. I think that is how, and why, it’s use was permitted in the poultry industry for so long. Not anymore though.

Yessir, indeed many of my trees are in the woods. We’ve got a few others in an “orchard” that is a few hundred feet away from any house, so we should be good.

I didn’t think you were picking on me, chikn. It’s something that everyone should know, and I’m sure that people don’t do their homework. I can’t tell you how many times I’ve seen people use pesticides (of all types) without consulting the label. It’s pretty scary.

That never made sense to me either. Initially I thought it mist be related to the skin or texture of some fruits holding the pesticide, like wrinkly skin, or peach fuzz or something like that. That would make sense because residue levels would obviously be higher. That clearly isn’t the case though because in your scenario, I’m certain blackberries would tend to hold residue better than an apple, and I’ve seen the same thing with other fruits.
Mystery to me.
I think a while back someone posted about these differences related to apricots and the differences were crazy.
I’m sure there must be something to it, but, like you, it’s lost on me.

The idea behind a zero PHI and a REI of hours or days, as I understand it, is as follows.

The REI is based on continual exposure of field workers to the pesticide during harvest. Exposure of workers is much greater than if someone were to simply eat a piece of fruit. Even following the REI, something like chlorothalonil will burn your eyes if you thin, or prune all day in the orchard. Inhalation and skin absorption are generally greater than what people would intuitively assume.

Fruits can be harvested w/ a zero PHI along with a longer REI by way of mechanical harvesting. Manual harvesting is also allowed if the labeled PPE is worn.

The EPA has a fairly complex methodology (that I don’t completely understand) for coming up w/ PHI on various fruits. It’s based on a lot of factors: How much of the fruit is expected to go through processing. How much is expected to be included in baby foods (The EPA has higher standards for foods expected to be fed to infants.) How much the typical consumer is expected to eat of the given food item. Different dissipation rates on different crops (i.e. The pesticide will dissipate faster on some crops than others.) are at least some of the factors.

Re: phosmet

I think most people know this, but wanted to mention for newer folks that phosmet/Imidan packs are not supposed to be opened. They are “water soluble” packs designed to be thrown whole/unopened into the tank. When the EPA required phosmet to be re-registered, part of the terms of registration were that the chemical be packaged in water soluble packs (along with longer REIs) to minimize applicator exposure to the pesticide. This action also effectively removed the pesticide from the homeowner populace because of the large areas required to be treated with one water soluble packet.

Bear in mind, I’m not judging anyone for opening the packets, just passing on information.


You’re probably right that Captan and Imidan might perform better at 4.5 to 5.5. I said a pH of 6 because that’s the last thing I’ve read as a general guideline pH for spray water. I don’t spray Imidan. I do spray Captan and it’s pretty stable at 6. As I understand it, once the spray dries, the pH of the solution doesn’t matter. Captan has a half life of 8 hrs at a pH of 7. I don’t know what the half-life is at 6 pH, but it would of course be longer than 8 hrs. which is plenty of time for me to get the spray on and dried before much of the compound is lost. Captan has a half-life of just 2 minutes at a pH of 9, so I definitely need to acidfy my water to use Captan.

The EPA has a “secondary” standard for the pH of drinking water which is b/t 6.5 and 8.5. Our water is listed as 9.4 pH in the printed material put out by our water supply. I’ve also tested it w/ a calibrated tester and come up with basically the same number (9.3 to 9.5). There’s no way I could mix and spray Captan in less than 2 minutes, lol.



Regarding breaking the packets open… that was one of my biggest reservations about using it. I’ve got a respirator and even though I’ve got a long beard I’m still going to wear it. I’ll wear gloves and the like as well. To me, that seems like the time that an individual would be most likely to have an adverse exposure.


Thank you for the information. I never considered mechanical harvesting or picking with PPE.

How did you gain so much knowledge about chemicals and the EPA?

I’m an industrial spy for the chemical industry. :wink:

Thanks for the compliment Blueberry. I suppose I’ve done a lot of reading over the years and asked the same questions to friends, who know more about these things than I.

I’ll add I try to give the best info I currently know, but I’ve always maintained the collective knowledge of this forum is greater than that of any individual. It’s a pleasure to learn little gems of info from this forum quite often. I wish I had time to read all the posts like Fruitnut and Muddy.

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"but I’ve always maintained the collective knowledge of this forum is greater than that of any individual. "

You hit the nail on the head. I can’t tell you how many times I’ve heard one thing from someone, and a complete opposite from another person. Having a place like this to get fairy standard/universal info is great, but I think what really shines on forums is the ability of members to deconstruct nuanced opinions/advice. By this I mean that most times there can be a conversation discussing the advantages and drawbacks of a situation. This allows us, and those of us who are less experienced, to decide what is best for our situation.

I’ve always been of the mindset that I need to make my own mistakes, rather than repeat the mistakes of those before me. I need to listen to someone with experience and weigh that with my own situation. While forums certainly don’t prevent us newer growers from making any mistakes, they sure as heck give us a better chance at dodging the major speedbumps on the learning curve.

I’ve learned that even local orchardists have a somewhat interconnected web of sharing info (pest pressure, etc…) and they are the pro’s. If it’s valuable for them, I can’t imagine how valuable it is for myself as a “hobbyist”.

Man that was well said. I remember how much a different fruit forum helped me years ago.

I had to sift through some misinformation, and information unapplicable to me (assume this is the case with any forum) but still benefited greatly from the knowledge.

And that there line from Olpea is exactly why I contributed when Scott offered us an opportunity to help out awhile back.

I have nothing to offer here, but man do I get a ton out of it!!!

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Rally, you need 2 Ziploc containers with tight fitting lids, one larger one for the unopened packs (it will still stink through the unopened packets) and a smaller one to hold your opened packet. Open it outside in late evening when the wind is very calm, and wear some latex disposable gloves.
You’ll need to keep a Ziploc bag (the kind with the zipper only…not the regular kind), in this, you’ll keep your measuring spoon. Write the mix ratio on that bag and/or on the container so there will never be any doubt of the mix ratio. Write both max and min application rates for different fruits (I forget at the beginning of the season). I suggest you use a ratio that will work for all your fruits. In other words, a ratio that may be max for one and min for another, that way you simply mix and spray until all your fruit is covered. No changing up ratios for different fruit types.
I wore a respirator also for a while, but have since given up on it though it doesn’t hurt and IS a good idea for the initial bag opening etc.
Only spray when the wind is dead calm and other obvious stuff. Keep children AWAY from the spray area beyond the REI. Imidan, as with all chemicals, are particularly dangerous to children for several physical / medical reasons, beyond just being smaller etc. It has to do with organ development and other things beyond my total comprehension. I’ve read all the data on it including the links to Autism / ADHD and although there is no concrete proof of the link, I think there is little doubt that one exists.

An interesting side note, Imidan and other organophosphates were initially discovered and pioneered by the IG Farben company during WW2 during the quest for a human exterminant which ultimately became Zyklon B. Organophosphates proved no good for this, but they immediately understood the commercial / agricultural applications for it and so the science for OP was born. I just find it interesting that something so useful for good purposes was rooted in some very sinister and dark history.

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  1. I think the REI stuff will be the hardest for us since some of our trees are in a somewhat regularly used area. We’ll just have to spray before we leave, and tell our neighbors not to let their dogs in the area. Most of those trees are fully grown standard trees, so even if I get insects I’ll still get a bushel of apples.

  2. There are a lot of drugs that have good origins and nefarious uses, or as you pointed out visa versa. Look at Warfarin. It is/was used as rodent poison because it is an anti-coagulant.

Lots of chemicals that may be inert to us can be almost identical with regards to structure. In general evolution has given a us a lot of specificity with regards to structure or pH conditions. It’s amazing, but can also be kinda scary to think about how closely one thing that is relatively harmless is to being deadly.

Look at the history of Thalidomide. One enantiomer is relatively harmless and an effective form of birth control, while the other enantiomer has horrible effects. So in this case, the same chemical compound (at least formula wise) can have 2 completely different affects because of the positioning of things.

Same with ibuprofen. Only one of the enantiomers reacts with our body, so when we take 100mg, we’re really only getting 50mg of the active ingredient. It’s been a while since I’ve taken Organic chem, so it might be that we get 100mg of the active ingredient, but we’re actually taking 200mg. Either way, approximately half of it is completely inert to our body.

At least to me, I think one of the most incredible things that has happened in the last 50 years is our development (and expanded knowledge) of chemicals (medicines, pesticides, etc…) that are incredibly specific to a certain host, gene, process, etc… This doesn’t necessarily mean that we eliminate the possibility of adverse effects, but it sure as heck gives us a great chance to lower those adverse effects when we use them properly.

Sorry for rambling!

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I enjoyed your thoughts and learned from them. Ramble on my friend!