Does Glyphosate have a Shelf Life After Open ??

[g_man]

I use Glyphosate to control but never conquer Glossy Buckthorn in a large marshy area - cut and squirt method. I had to buy gallon container to get it at 41% so it has lasted me several years. Maybe it is my imagination but it definately seems to be less effective now in preventing resprouting. Thus the question. Thanks.

gg

[Bandmill Bandit]

Glyphosate resistance is a well documented reality and is how "roundup ready" crops were developed. You are  creating a super weed in all probability.
  

[btulloh]

Try something with Triclopyr.  Good for tough woody brush. 

Sometimes I keep glyphosate for a couple years and it doesn't seem to lose any mojo.  I leave mixed glyphosate in a plastic sprayer over the winter and I swear it seems MORE potent.  Just as potent anyway.

(No comments required on my bad sprayer etiquette.  I buy cheap pump sprayers and treat them badly.)

[g_man]

Wow - I didn't see that coming Bandit. But it makes sense. I am no farmer or gardener and a weedy lawn is OK by me so as they say - ignorance is bliss, I guess. I have been using the stuff for probably 10 years or more down in that marsh. Time to rethink............ Thanks

gg

[WDH]

Like btulloh, I think that Garlon is a better choice.

[petefrom bearswamp]

I am still on my 2 gallon jug bought in 1995.
Still effective but I only use it on grasses and weeds, not woody matl.
It is effective on multi flora rose too.
I mix 2% to make sure.

[Mad Professor]

Will keep better tightly capped away from light and heat.  Not sure of shelf life.  I know I've used 2-3 year old stuff that still works.

[1countryboy]

"I use Glyphosate to control but never conquer Glossy Buckthorn in a large marshy area - cut and squirt method."

Roundup or Glyphosate works best on fast growth.   So do not cut it and then apply the product.   It is a contact chemical.  Roundup or its generic brother will NOT prevent regrowth of other seeds in the soil.  Mairstail was an example and Roundup was fantastic until the weed became resistant.   Switch off with different chemicals.  

[1countryboy]

Roundup or Glyphosate works best on fast growth.   So do not cut it and then apply the product.   It is a contact chemical.  Roundup or its generic brother will NOT prevent regrowth of other seeds in the soil.  Mairstail was an example and Roundup was fantastic until the weed became resistant.   Switch off with different chemicals.

[John Mc]

Roundup or Glyphosate works best on fast growth.   So do not cut it and then apply the product.   It is a contact chemical.  Roundup or its generic brother will NOT prevent regrowth of other seeds in the soil.  Mairstail was an example and Roundup was fantastic until the weed became resistant.   Switch off with different chemicals.  

Actually, one of the recommended ways of combating Buckthorn is with the "cut stump" method: Cut the stump off low, then spray or brush on Roundup/Glyphosate. On my own property, I've found that I need at least a 25% concentration of Glyphosate to be effective (Going lower means some of it survives. I often just use the 41% concentration in full strength). I need to apply it very soon after the cut (the sooner the better, within a few minutes). It's also important to do it during the right time of year. Cut stump treatment will not prevent resprouting if done when the tree is dormant (e.g. in the Winter). It's also not effective in the flush of Spring time. I get good results if I treat it after the spring flush is done, and before the leaves turn color in the fall. In my part of Vermont (Champlain Valley) this usually means from July through about now (sometime in November).

It should be noted that "RoundUp" is not approved for application in wetlands. There are other glyphosate combinations that are approved for wetland use (Rodeo is one such example). However, I believe you can't get that in VT without a license either.

Trying something else if the Buckthorn is becoming resistant to Roundup/Glyphosate is a good idea. As others have mentioned Garlon 4/Triclopyr can be effective. I've seen folks in our area use a basal bark treatment of Garlon 4 mixed with diesel with good results. (It's also approved for foliar application, and for cut stump.) However, legally you'll need to hire a professional, because...

Here in Vermont, you need a license to purchase and apply just about anything other than RoundUp or generic equivalent glyphosate formulations. So a landowner who wants to do it themselves has limited options. (A landowner can also only legally use glyphosate on their own land. You can't help out a friend by applying it on their land.)

Lastly: Vermont has a gag rule about making recommendations on the use of herbicides unless you have a commercial applicator's license. The state was actually going after people who dared to speak about it some years ago. They came to their senses and realized that freedom of speech means they can't prevent someone from saying "this is what I did on my property, and this is how it worked". However, they are still quite touchy about someone making recommendations to a friend. So I can say "Using 30% RoundUp in a cut stump application on Buckthorn worked for me." I can't say "You should use RoundUp at 30% in a cut stump treatment on your Buckthorn". It is legal for "unlicensed" Vermonters to provide links to resources which describe the proper application.

[g_man]

Yikes - Some of that is a little scary John. Maybe I need to move east about 7 miles and get on the other side of the river.

Maybe I do it to early. I try to beat the worst of the ticks and the heat - so mid May probably. The stuff I use is Gordon's Big-N-Tuf 41% Glyphosate from TSC. I use it straight.

gg

[John Mc]

Yeah, Vermont is a little weird about some of this stuff.

May is definitely too early. For the cut stump treatment to work, the plant needs to be sending reserves down to its root system. In the spring, all of that stored energy in the roots is being sent up to the rest of the plant. I think of it sort of like the plant is spitting the glyphosate out.

[g_man]

Thank you !!!! - that explains a lot. I used to do it in the late summer to early fall but I changed to spring the last couple years because I thought it would be better to cut them before all the berries were formed. The common yellow throats were loving them. But then my results got poor so I thought maybe the Glyphosate aged. Seems I just out smarted myself. I will use it later as you suggest and see what happens.

gg

[John Mc]

I'm not saying glyphosate does NOT have a shelf life... I have no idea on that score. However, changing the timing should help a lot.

[1countryboy]

Private Applicator:  Any person producing an agricultural commodity on land that he/she owns or rents, and who uses, or supervises the use of a restricted use pesticide, must be certified.

Examples:  Farmers of all kinds including, but not limited to, dairy and those that grow row crops, forage, vegetables, berries, apples, grapes, nursery stock, Christmas trees, etc.

To become a Certified Private Applicator you need to take and pass the Private CORE Exam administered by the Vermont Agency of Agriculture, Food & Markets.

Vermont Agency of Agriculture, Food & Markets 116 State St Montpelier VT 05620-2901 802-828-2431 Home | Agency of Agriculture Food & Markets
 
APPLICATION FOR A PRIVATE PESTICIDE APPLICATOR CERTIFICATE
 
Application is hereby made for a certificate to apply pesticides under the provisions of 6 V.S.A Chapter 87 and regulations pertaining to the commodity groups indicated below. The fee, as of July 1, 2016, is $25 for a five-year certificate. 
 
Each state has its own rules and regulations.  Ohio is very similar.  But, The federal EPA will inject its "interpretation".  Good or Bad and is a regulatory body seemingly answerable to itself.   Please follow labels.  Those of us in production agriculture (crop production that includes tree farming) depend on the chemicals working on weeds.   Weeds develop resistance faster than science can develop new chemicals.  Prime example is/was Roundup and the generic s.   The wonder chemical to control weeds (marestail), (Poison Hemlock) as examples.   Now we must have a license to apple fertilizer.  Because Lake Erie had algae.  Was no mention of the fecal matter on the beaches along the lake from "treated or flushed" sewage into that large lake by cities, but agriculture was blamed.  Point is that everyone is responsible for the safe use or government will step in and that is a disaster.   

[John Mc]

Private Applicator: Any person producing an agricultural commodity on land that he/she owns or rents, and who uses, or supervises the use of a restricted use pesticide, must be certified.

and in Vermont, every herbicide other than RoundUp and its generic equivalents is deemed a "restricted use pesticide".