http://www.forbes.com/sites/timworstall/2012/09/20/monsantos-gm-corn-and-cancer-in-rats-real-scientists-deeply-unimpressed-politics-not-science-perhaps/ "Their claim is that the rats fed GM corn and Roundup got more such tumours earlier than the control group. The criticism of this finding is that the control group was simply too small to allow such an observation to be made with any certainty. And they have not conducted, or at least not presented, the standard statistical tests which would allow they or us to determine whether the results were the outcome of pure blind chance." http://arstechnica.com/science/2012/09/anti-gmo-researchers-used-science-publication-to-manipulate-the-press/ "Any journalist that wanted to receive an advance copy was required to sign a non-disclosure agreement before receiving one. That agreement prohibited the outlet from sharing the results with any outside experts before the embargo lifted. In other words, if a press outlet wanted to be one of the first to cover the story, it would have to run the story without having any experts sanity check the paper." "The embargo lifted during a live press conference from the researchers, hosted in London in cooperation with the Sustainable Food Trust. The SFT conveniently had a press release prepared; a release claiming that the research was "supported by independent research organization, CRIIGEN." However, this neglected to note that the paper's lead author, Eric Seralini, is on the CRIIGEN board." Conflict of interest, and keeping the newspapers from doing any fact checking before publication ... that's not accepted protocol. https://embargowatch.wordpress.com/2012/09/21/stenographers-anyone-gmo-rat-study-co-sponsor-engineered-embargo-to-prevent-scrutiny/ " One of the main reasons for embargoes �" if you take many journals at their word �" is to give reporters more time to write better stories. Part of how you do that is talking to outside experts. And scientists �" ones interested in science, anyway, not those interested in spin and political points �" should welcome that kind of scrutiny."

In my weeds class decades ago we were taught the effect of diligent tillage on bindweed, a nasty agriculture problem if left unchecked. Specifically, research was conducted to determine what had to be done to kill the whole plant. What was discovered was that if one never allows the above ground growth to get more than 8" long before removing it at ground level or deeper and continuing this for 2 straight years, the whole plant would use up it's reserves in that deep root and die. Letting the top grow more than 8" lets the plant send reserves back into the root system so you have to never let that happen. Years ago when we bought this place the north garden plot was a bindweed pit!!! I spent 2 years with the wheel hoe assaulting the bindweed as was suggested in the research and can confirm that it works extremely well. Didn't even try to grow anything in that plot those 2 years to make it easy to nail all bindweed mercilessly. Of course, those were just crucial battles, the war isn't over as there is bindweed in areas surrounding that plot that tries it's best to creep in and must be stopped at the borders.

Keith wrote, "I was thinking: isn't it likely that whatever genetic trait confers survival value on these particular plants in the face of glyphosate (Roundup) might be a weakness in every other circumstance?" Tolerance of glyphosate alone may not always be a disadvantage in areas not contaminated by Roundup. However, a glyphosate tolerant strain may survive in contaminated soil despite any other inherent weaknesses. Furthermore, it does happen that persistent selection for one or a few characteristics can lead to an accumulation of undesirable traits. There was the case of a man who was making great progress in improving the colors and size of sweetpeas. He was surprised to learn that his improved strains had lost much of their fragrance. Here's another case: The Russian fur industry decided to domesticate Silver Foxes, to make them easier to handle. Within 25 years they had succeeded in developing a breed that was as domesticated as dogs. The program was not a complete success, however, because the foxes began to vary in undesirable ways. Patches of white appeared on some specimens, along with floppy ears, and tails of variable lengths. Some had curled tails. As has happened in other organisms, selection for uniformity in one trait brought variability in others -- though there had been no great variation before the selective process began. Belyaev, the breeder, had carefully avoided inbreeding. Karl Here is a link that might be useful: The Farm Fox Experiment

If my post came across as patronizing to the original poster or to any lurkers, I apologize. I don't know you so I can't judge whether you are a careless weekend gardener or a professional. My comment about following label instructions was intended for the larger audience of GW in general and the OP only if you didn't know. Your comment that you were going to spray again "using a heavier concentration that that which is instructed on the bottle" was what caused me concern. Nothing is entirely safe and when someone advocates the use of a chemical in increased concentrations they may be endangering more than just themselves. The increased dose of glyphosate may not cause any harm to the user or the environment or anybody else. But others with less knowledge or experience may feel that if someone used an increased concentration of this product to clear up a particularly difficult problem, then it's ok to increase the concentration of one of the more dangerous pesticides to combat some problem they are having and the results may be disastrous to the user, the environment, AND to the innocent neighbors! This is not a case of just the user "getting what he deserves." I've seen the damage done by herbicides when the directions or precautions on the label were not followed. It's not a pretty sight when the neighborÂs yard loses grass and shrubs and flower beds, and itÂs potentially a very expensive mistake by the user. My post was intended to bring attention to the fact that the label information is important and should be followed. If the product doesn't work as expected, maybe the user's expectations are too high or they are not using the proper chemical or technique and should research the problem more thoroughly. And to answer the original question, no, I haven't seen anything to indicate that poison ivy has become immune to RU - yet! But anything's possible! Glyphosate resistant plants are being discovered fairly regularly. An article published by Perdue says, "It is important to understand that these resistant biotypes are out there and that resistance can develop with continuous use of herbicides with the same mode of action (how a herbicide controls a weed)." (http://www.ppdl.purdue.edu/ppdl/weeklypics/7-14-03.html) So if your PI or any other plant has developed resistance or is a naturally resistant strain, IÂm sure the agricultural community and pesticide manufacturers will be interested in hearing about it.