How much dicamba is required to injure soybeans?

Yesterday, I posted some photos to twitter, and have been asked to provide a little bit of context. My goal with these photos was not to “raise an alarm” – I was simply trying to provide a visual illustration of how susceptible soybean plants are to the herbicide dicamba. Recently, I published a meta-analysis of published literature on this topic. In that paper, I estimated the amount of dicamba required to cause both yield loss and visible injury symptoms. The …

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Have genetically engineered herbicide-resistant crops increased or decreased herbicide use?

It’s a simple question. And at first glance it seems like there should be a simple answer to this simple question. We have planted millions of acres of genetically-engineered (GE) crops, a vast majority of which are resistant to herbicides. In the U.S., we’ve collected lots of herbicide sales and usage data, spanning the entire time period when GE herbicide-resistant crops went from non-existent to dominating the landscape. So we should be able to simply look at the herbicide data before …

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Palmer amaranth – current state-level distribution in the US

Palmer amaranth is native to the southwestern United States, and has been recognized as a problematic weed in the southwest and southeastern US for many years. Each year, this species seems to move further north. I’ve been trying to keep an accurate state-level distribution map for this weed, and thought I’d post it here for anyone else who might be interested.   Data sources: PLANTS database (https://plants.usda.gov) California, Nevada, Utah, Arizona , Colorado, New Mexico, Nebraska, Kansas, Oklahoma, Texas, Wisconsin, …

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Glyphosate and cancer – revisited

Recently, a jury in San Francisco, California recommended that Monsanto be forced to pay $289 million to a man who has been diagnosed with non-Hodgkin lymphoma. It was a pretty stunning result from a court case that has been watched very closely. I haven’t read the court transcripts, and I don’t know what the jury was told or what was withheld from them. And I have no desire to make accusations that either side was acting in bad faith. So …

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Remembering Gustavo

This has been a difficult year. One year ago, I learned that my best friend had died in a motorcycle accident. He was traveling to a meeting in California – a meeting that I was also attending. I found out about Gustavo’s passing just a few seconds before the flight attendant made me put my phone into airplane mode. I was alone, without the ability to communicate, and I’d just been told I would never again get to see the …

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Dicamba-Resistant Crop Timeline

Below is a non-exhaustive timeline of dicamba and dicamba-resistant soybean. I’ll add to it and update it as needed, perhaps with interesting information or current status updates. I’ve mostly put it together for my use in teaching/extension, but thought I’d post it here in case it is useful to others. 1958 Dicamba was discovered and first described. 1967 Dicamba was first registered for use under the trade name ‘Banvel’. It was widely used over the next 30 years to control …

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Occam’s Razor rarely includes conspiracy theories

Proponents of genetically engineered crops (often called GMOs) often decry the anti-GMO movement for promoting implausible conspiracy theories. I’ve been blocked on Twitter by people claiming the Department of Agriculture and Supreme Court of the United States were simply pawns of Monsanto and the pesticide industry. I’ve pushed back against those saying that pesticides are the cause of microcephaly (instead of the Zika virus). I’ve written blog posts explaining the evidence that debunks some of these improbable stories. Spreading these …

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Soybean Response to Dicamba: A Meta-Analysis

UPDATE: This article has now been published in Weed Technology. The open access, formatted and copy-edited article is available here: Kniss AR. Soybean Response to Dicamba: A Meta-Analysis. (2018) Weed Technology. 32:507-512. doi: 10.1017/wet.2018.74  Abstract. A meta-analysis of 11 previously published field studies was conducted with the objectives to 1) estimate the no observable effects dose (NOED) for dicamba on susceptible soybean; 2) evaluate available evidence for hormesis, or increased soybean yield in response to low doses of dicamba; 3) …

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What does a pesticide taste like?

I honestly can’t believe I just typed that title. But here we are. The notorious Gilles-Eric Seralini published a paper recently called “The Taste of Pesticides in Wines.” As a part of the study, people were asked to choose a preference between organic and conventional wines. Okay, fine. But then the participants were given glasses of water, some of which were spiked with pesticides at doses purportedly found in bottles of wine. This is bizarre on so many levels. For …

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