I've used captan I have stored on my grapes as directed for four years and they did not get any fungus. Like you I buy bulk and use bonide captan which according to bonide powders have an indefinite shelf life when stored properly. The liquids have a short shelf life.

Here is a link that might be useful: bonide captan

This post was edited by ClarkinKS on Sat, Nov 1, 14 at 16:00

I've never heard of powdered fungicide having a particularly short shelf life and commercial formulations of fungicides I use don't have info on the container of when they were manufactured like the short-lived Asana pyrethroid which is notoriously short lived at a 2 year span of adequate potency. Asana has the manufacturing date clearly on the container it comes from so it can't be missed.

Please let me know the source of your info because it would be helpful for me to be informed about this. Maybe I'm missing something.

I usually use liquid formulations of Captan for convenience- the commercial versions aren't that pricey, but these formulations tend to clot up after a season. Definitely best for your purposes to go with the granules (or powder if that's how it comes in the package you order- I use 70% which comes in granules). .

Yeah...I went and double checked to make sure they were listing it as WP and indeed they are. In one of the links harvestman, I think it shows the WDG also and it seems to me it was the same as WP.
I also checked two different Captan labels and neither made any mention of storage life whatsoever. There are a lot of sites with this info, but possibly they are copying from one another.

http://web.extension.illinois.edu/cfiv/homeowners/031025.html
(3 year shelf life - WP)

http://psep.cce.cornell.edu/facts-slides-self/facts/gen-peapp-shelf-life.aspx

(3 year shelf life - WP)

http://idealchemicals.en.alibaba.com/product/60005971055-800167079/Captan_fungicide.html

(18 month shelf life - WP)

The above site is an import chemical supply dealer offering 99% purity Captan. Presumably this would then be combined with the micronized clay dust to 50% , 80% or whatever concentration was being made. They claim a shelf life of just 18 months. Maybe the mixing with clay prolongs shelf life.

This post was edited by Appleseed70 on Mon, Nov 3, 14 at 1:28

"There are a lot of sites with this info, but possibly they are copying from one another."

That seems to be the case w/ the first two links in your post above.

I wouldn't trust the third site (...alibaba.com)

I think how long captan will last has to do w/ temperature and relative humidity.

One of your links indicated WP and WDG have problems w/ lumping. To control humidity, I place pesticides in a 5 gal bucked w/ a lid. I keep them in a cool, but dry place. I've not had issues at all, keeping the WPs or WDGs dry.

"There are a lot of sites with this info, but possibly they are copying from one another."
That seems to be the case w/ the first two links in your post above.

I don't think so in this case olpea, because the first two links gave different shelf lives to Captan.

I wouldn't trust the third site (...alibaba.com)

Why not olpea? Because it's a Chinese importer? If so, I hear you, but it wouldn't be in their best interest to reduce shelf life...if anything one would think they would cleverly lengthen it. I figure if they're smart enough to make it they can probably competently test it as well.

I think how long captan will last has to do w/ temperature and relative humidity.

It absolutely does and both sites indicated exactly that.

One of your links indicated WP and WDG have problems w/ lumping.

If what you are referring to is what I remember reading they were stating that these were signs of extended shelf time or poor storage indicating the compounds effectiveness has been compromised. Not an issue with the product in general.

To control humidity, I place pesticides in a 5 gal bucked w/ a lid. I keep them in a cool, but dry place. I've not had issues at all, keeping the WPs or WDGs dry.

I do the same thing Olpea and I haven't had any issues either and my basement isn't what I'd define as being "dry". It's as most basements are "damp" or high humidity by their very nature. I sometimes don't even fully close the zip-lock seal on my sulfur and I just keep it on the shelf. Unbelievably it has never clumped or anything even close. Just stays dry, smooth and airy powder. Thing is, you and I only know that we both have dry materials, but neither of us can attest to what effectiveness remains without some sort of laboratory testing.
I'm guessing someone has done this testing and that's where the shelf life numbers come from.
I'm not sure what to make of it. I couldn't find any manufacturer disputing their claims though and for all we know their data may have come from manuf. testing.

Appleseed, I get my info from Cornell- but what they supply for commercial growers. Over the years, I have gotten none of this input from them and I wonder if it is because of the belief that commercial growers cycle through their pesticides reliably in short order.

This would be an incorrect assumption, I think, judging from what I've seen in some storage sheds of commercial growers (I sometimes will buy material from a grower when I run out and don't want to drive to my far away supplier).

I am going to present your question to the consultant that works with my CPS outlet for commercial growers in the Hudson Valley. I don't trust the recommendations in your Cornell link because I think they may be assuming that amateurs are unlikely to properly store pesticides. Or not. I know that this consultant often scoffs at assumptions made by the Cornell gurus because of direct experience helping to manage thousands of acres of commercial production.

Not that a contradicting opinion would necessarily settle the issue. Your safest bet is obviously to follow the most conservative estimates. However, packaging for commercial growers may often be better than that for small homeowner quantities in addition to their being more likely to be stored in a cool dry place inside a water tight container.

Thanks for bringing this issue up. I learn something new on this thread on a regular basis and you are relentless in digging up new info, which is good. I have some 4 year old Captan that may now have to be delegated to toxic waste status thanks to your input.

"I don't think so in this case olpea, because the first two links gave different shelf lives to Captan."

Appleseed,

Maybe I'm missing something here, but the first two links show a 3 year shelf life for Captan. In fact, the IL link says they got their info from Cornell. The Cornell link is a bit hard to read in my browser, but it shows 3 yrs for Captan. In their format, the compound is listed followed by a comma, the type of formulation, then the shelf life.

I also did a Google search, and all the websites I came across show a 3 yr shelf life for Captan WP.

I mentioned the lumping because that seems to be the main issue w/ WP shelf life If you don't see lumping/caking and the product mixes well in the tank, it's probably good.

The link below lists Captan WP w/ a three year shelf life, but they also list phosmet w/ a 2-3 yr shelf life. I'm pretty sure phosmet has a longer shelf life than that. Don Yellman, who used to be a regular on this forum, indicated he bought a "life-time supply" of phosmet and used it for years. He never indicated he had problems w/ efficacy. On the contrary, he regularly recommended the product to other forum members.

Your right, the only sure-fire way to know is to scientifically test persistence in undiluted form. I just don't know if Cornell did that w/ Captan, or they simply had problems w/ caking. My guess based on general comments of issues w/ wettable powders is that caking was the issue. I've personally kept some Captan longer than 3 yrs and it looks and seems to perform the same as brand new stuff.

Keep in mind you also have no idea how long the chem distributor had the compound in his storage. I've bought some pesticides, which, judging from the looks of the package, seem to have sat in storage for many years. They seem to perform just fine for me.

For the most part, I store pesticides in locked lockers or in 5 gal. buckets w/ snap on tops under cool temps w/ controlled humidity (w/ a dehumidifier) which may prolong the shelf life of some of the pesticides I use.

"Why not olpea? Because it's a Chinese importer? If so, I hear you, but it wouldn't be in their best interest to reduce shelf life...if anything one would think they would cleverly lengthen it. I figure if they're smart enough to make it they can probably competently test it as well."

Who knows how reliable the info. is on the Website. Even American manufactures will blanket state that their pesticides should be used w/in 2 seasons, even though Cornell's tests show a shelf-life much longer. I trust the Chinese importer site even less.

It's probably in the manufacturer's best interest to place the most conservative estimate on self-life (for the worst possible storage conditions). That way the product will still work for Joe six-pack, even if he stored it crappy. Additionally, the manufacturers probably don't mind consumers throwing out perfectly good product and re-buying more. Perhaps not unlike car dealerships compressing maintenance schedules, thereby unneedly replacing fluids/filters at the customer's expense.

All I'm saying is that I wouldn't dispose of a pesticide just because it surpassed Cornell's test numbers. If it's caked, settled out, or won't mix in the tank well, then it's time to dispose of it IMO.

Here is a link that might be useful: Utah State factsheet

Harvestman:
When do you think you'll see this guy? I too wondered also about what they "assumed" storage was like when giving these numbers. I concluded that they must mean under ideal conditions, but like olpea and you, my gut says this isn't right. I'm not sure why I feel that way.
Are you sure this outlet guy will even know anything? Maybe it's just a job for him and he don't even know much about it for all we know. At the very least he should know someone to call that does have an answer.

Olpea:

The Illinois site say 3 years and the Cornell one 2 years. Both sites say Imidan's shelf life is indefinite, but I seen another site that listed Imidan just like your Utah link did. I just laughed and dismissed it because of this. I figure anything that deviates that far from what university data says (it was a newspaper site also) is discredited right off (for me at least).
I also agree with you Olpea, I wouldn't toss out Captan that was 4 years old either. I would however probably bump up the mix rate unless H'man comes through with better info.

Harvestman and Olpea:
Hey...neither of you commented on the Captan "coloring up" fruit. Did you guys already know that? Actually it was usually described as "brightening" fruit. I don't think they meant by the absence of SB and the like either. As I read it, they meant color improvement by some means.

Did you guys also know that Captan is a odorizer put into natural gas? I always knew it was added odor, didn't know it was Captan. I also read that Captan contains sulfur in it's chemical make up. I know this info isn't really pertinent to anything...just found it interesting.

I forgot about the coloring up part, but I wonder if this doesn't occur with all fungicides that help control summer fungus. Summer fungus may do more than add its own color but also stop the sun from interacting with the fruit the same way any other kind of shade does.

Actually, I didn't notice that claim in the Cornell guidline, but I did not read it carefully beyond shelf life issues. That was the real attention grabber for me and may completely change the way I consider using older pesticides I have in my cabinet. Once again, I'm very thankful for your info gift.

I knew it was the sulfur component that makes Captan so incompatible with oil. It is often mentioned in guidelines.

"The Illinois site say 3 years and the Cornell one 2 years."

Apple,

The Cornell link you posted above says 3 years shelf life for Captan.

It reads specifically: "Captan, wp 3"

Where are you getting that Cornell says 2 years?

They don't put Captan in gas regardless of what Wiki says. They use ethyl mercaptan in gas - chemical formula C2H6S, or methyl mercaptan - CH4S

Captan is a completely different compound w/ chemical formula - C9H8Cl3NO2S

I didn't know Captan would increase coloring. I only use it early in the season anyway. I try to use softer compounds closer to harvest, if possible. Also, like other WP or WDG it doesn't really dissolve in water. It just suspends the particles in water w/ agitation. The end result is that it leaves an unsightly film on the fruit if used later in the season.

The Cornell link you posted above says 3 years shelf life for Captan.

It reads specifically: "Captan, wp 3"

Where are you getting that Cornell says 2 years?

Look more closely Olpea. It is arranged strangely, but it says 2 years.

, wp 2 keep dry Captan,

Shelf life Pesticide (years) Comments -------------------------------------------------------------------------------- Sevin, wp several flowables will settle Diazinon 5-7 Disyston 2 Malathion, wp indefinite decomposes under high temperatures Metasystox-r 2 Methoxychlor, wp indefinite Imidan, wp 2-3 Benlate, wp 2 keep dry Captan, wp 3 Thiram, wp 4 keep dry, below 100 degrees f. Ammate, sol. Salt at least 2 no low temperature limit Casoron, 4g at least 2 Dacthal, wp at least 2 Roundup, liquid at least 2 stable below 140 degrees f., Do not freeze Kerb, wp at least 2 Paraquat, liquid indefinite very stable, do not freeze Princip, wp indefinite Surflan, wp 3 Treflan, g 3 loss 15 -20 % activity when stored at 100 degres f.

I thought Captan was just short for Mercaptan. You're right though...I think I may have read that on wiki...lol

Apple wrote:

"Look more closely Olpea. It is arranged strangely, but it says 2 years.

, wp 2 keep dry Captan,"

My response:

No. The format is the compound listed first then the pesticide shelf life, then comments.

Look at the first compound Sevin. It has the compound, then the formulation (for some reason they don't list the shelf life on Sevin) then comments. The next one is Diazinon, 5-7 years of shelf life (no comments listed).

Look down at the very last compound. Treflan G, shelf life is 3 years (comments) loses 15-20% activity when stored at 100 degrees F.

Again, it's Captan wp, 3 years of shelf life.

sorry olpea...it's 2 years.
Look at the comma placement and look at Imidan as it's the "indefinite" listing there.
It does appear as though the writer switched it up there, but I don't think there is any mistaking they are saying 2 years for Captan. but whatever we're in the ballpark.

"Look at the comma placement and look at Imidan as it's the "indefinite" listing there. It does appear as though the writer switched it up there, but I don't think there is any mistaking they are saying 2 years for Captan"

Apple,

The writer didn't switch anything up. As I indicated earlier. The format is the Compound, followed by a comma, then comes the formulation (wp), then the shelf life, followed by comments (when there are comments). I don't understand why you can't see this (Occasionally there are some comments left out, or self life left out, or a comma omitted - perhaps that's what is throwing you off.)

The Imidan entry also follows this format "Imidan, wp 2-3"

Therefore, according to Cornell, Imidan has a 2-3 year shelf life. This matches the link I posted earlier from Utah State. Contrary to your earlier statement, the IL link you posted does not list Imidan/phosmet as indefinite. It doesn't even list Imidan/phosmet.

Cornell lists Methoxychlor as indefinite (i.e. Methoxychlor, wp indefinite) not Imidan.

This is consistent w/ what one would expect from studies based on environmental persistence. Methoxychlor is an organochlorine w/ a much longer environmental fate than Imidan/phosmet.

The IL link, along w/ the link below, as well as the Utah State link I posted all seem to take their info from the Cornell link you posted. Their comments are even word for word from the Cornell link. These other sources all verify the format I have tried to explain to you. Your interpretation of the Cornell format seems to be unique to yourself.

I suppose I have nothing further to add in this regard. If you can't see the format/pattern in the Cornell link you posted, I don't know what else to say. It's so obvious to me.

Here is a link that might be useful: Hummert International Newsletter

I stand corrected olpea.

I thought imidan had a indefinite shelf life (or was reported to have). It seems as though they are indeed speaking of Malathion instead.

I've changed the initial post with the links to 3 years. The truly bad news is that now I have 5 lbs. of Imidan to use up in the next 2 years. That's even worse than 5 lbs. of Captan in 3 which is what caused me to create the post in the first place. I was really hoping you or harvestman was going to tell me all this data was wrong and Captan would last for a decade or something. I'm going to have to find some smaller quantities at better prices or just quit with this stuff.
Again. my apologies. You are indeed correct. Sometimes I amaze myself at how blind and dumb I can be.

I wouldn't assume the data is correct, at this point. You need to see the research it's based on- Cornell isn't THAT reliable. I am going to try to get more info about this from my own sources, but you should contact the manufacturer of Imidan itself. I've done so in the past and they were very responsive. Just don't let them know you are a home grower and they may take you more seriously.

I have read on this forum of folks using the same batch of Imidan for a decade and I'm still using Lorsban I purchased probably 20 years ago and it sure seems to be working- some trees have borers when I spray and borers disappear after and the stuff still smells terrible.

I'm pretty sure those estimates are highly exaggerated, but I'm no a scientist.

Greetings:

I buy Captan 50 in 5 lb bags. Just used the last of it this past season. Seemed to work well. the Captan in the small bag I bought to finish out this past season when I ran out was much lighter in color than what was left of my old supply but I had no issues with it. It lasted me for
about 4-5 years.

I have stored and used Phosmet for 8 years with no noticeable loss in insect control.

I did notice that since I have few peaches so use little, my chlorothalonil seems to work only for about 6-7 years and then provides no results. I learned that the hard way and now date my container when purchasing it.

I am switching to Captan 70 granular for next year so I hope it stores as well as my Captan 50 WP did. I do keep them in a cool dry site and all is basically triple bagged to keep out moisture (and hopefully reduce the smell in storage).

Spartan your experience is kinda what I was expecting. I thought the manuf. would be saying something like 5 for Captan and maybe something like 8 for Imidan with the reality being longer yet, but with somewhat reduced effectiveness.
At those numbers I'm ok with buying 5 lbs. of anything. The cost is just ridiculously lower with the larger quantities.