OSU herbicide specialist Mark Loux

A weed’s dream come true

By Dusty Sonnenberg, CCA, Ohio Field Leader, a project of the Ohio Soybean Council and soybean check-off

It is a weed’s dream come true, that is if weeds had dreams. After 35 years of service as the Ohio State University Extension State Weed Specialist, Mark Loux, (a.k.a. Dr. Death to weeds) is retiring. 

Loux has been a farmers’ best friend and a weed’s worst nightmare. While a true statistical count has not been conducted, it could reasonably be estimated that Loux is responsible for the literal death of millions, possibly even billions of weeds in the State of Ohio and around the world. Add to that number the untold millions of weeds that were never able to germinate because of his persistent recommendation for the use of residual herbicides, and it is no wonder that the weed world is breathing (or respirating in plant terms) a collective sigh of relief. 

Loux’s career in weed science began, in part, due to his dad, who worked as a chemist for Dupont on the East Coast.

“When I was getting a degree in plant science at the University of Delaware, he let me know about their internships,” Loux said. 

Loux ended up accepting a summer internship in 1980 and then moved to Illinois to work at their research farm after graduating.

“In the middle of that, I figured out I wanted to go to grad school in weed science,” Loux said. 

After earning a Ph.D. from the University of Illinois, he took a position at The Ohio State University specializing in weed management in 1987. For the last 35 years, Loux has conducted numerous research projects, field days, winter agronomy meetings, and the production of the state’s weed control guide. 

Looking back over his career, Loux has seen extensive change in the weed control part of the industry. 

“Back in the 1980s we were just looking for anything new that we could get for control for some of the tougher weeds,” Loux said. “Around 1985 we did not have a lot of great soybean herbicides, then we got into the ALS inhibitors, and those solved a lot of the issues we had in beans with things like cocklebur, giant ragweed, common ragweed, the things we didn’t have good control of. We came into the 1990s getting good control, and then went to the other side and started to see signs of ALS resistance.”

Other memorable periods included technologies like glyphosate tolerant crops. 

“Round-up Ready started in 1996. The argument was had in the weed science community in which some scientist felt that farmers would be conservative with the use of this new technology, but I said, ‘This is Round-up and it is going to annihilate everything.’ And, of course, it did until about 2002 and we started to develop glyphosate resistance in the weeds,” he said. “We had almost completely clean fields everywhere and then around ’02 to ’04 we started to see marestail resistance showing up. Then we started putting things back in to get back to where we needed to be.”

The situation, in some cases, got worse before it got better. 

“I think we struggled before Liberty Link took off, and then before Enlist and Extend and some of the baggage, we were trying to put a bunch of stuff back into the chemical programs,” Loux said. “My approach had always been not to overly simplify programs because you are just going to be battling Mother Nature and she will always win. Since that time, we have developed some really good technology, that has some baggage, but we also evolved to have 4 to 5 really tough to control weeds. In the 80s there were a compliment of weeds to control, but we developed chemistries to control them. Now we have weeds with multiple types of resistance in these 4 or 5 species. They have really tough biology and are not going away. They are putting pressure on our current platforms such as Liberty Link and 2,4-D and Dicamba, which will probably break at some point in certain species.”

Constant evolution has been a staple of Loux’s career.

“It is interesting. We conduct a lot of herbicide evaluation. Early on I would give talks saying that this is what this herbicide does, or this is what this herbicide will control. It changed in the mid 2000s and to more of this is what you need to do with this particular platform to get control of a specific weeds like giant ragweed or marestail. Now we are saying this is what you need to do to keep waterhemp out, or keep Palmer out and here are the approaches you need to take to keep getting control,” Loux said. “Today the weeds like giant ragweed, common ragweed, waterhemp, and marestail are still tough weeds to control. Throw in a few dandelions and you’ve got some really good weeds that are just good at what they do. They are just tough weeds.”  

When it comes to retirement, though, the weeds did not defeat Loux. 

“My goal was to retire and hand the program off while it was still going strong,” Loux said. “The department chair had a transition plan, and that helped make the decision easier. We have approval from the college to replace my position and another one. We still have one Extension weed scientist, Doug Douhan, who is located in Wooster, and also Alyssa Essman, who has been my graduate student and is well known in the Extension community in the state. She has taken on multiple roles already.”

While the weeds may be breathing a momentary sigh of relief, it is not for long. Loux still has plans to harass weeds in his retirement. 

“The eastern part of the state still has some pasture weeds that are a problem such as autumn olive and multi-flora rose and Japanese knottweed,” Loux said. “I started a project that I will continue in my Emeriti status with some Extension educators in that area to look at getting control of autumn olive and multi-flora rose. It will be a change from corn and soybeans, but it will be fun.” 

After a long a successful career, Loux will be missed by farmers around the state and his former co-workers at Ohio State, said Alyssa Essman, with OSU’s Department of Horticulture and Crop Science.

“In his time at Ohio State, Mark led an applied research and extension program focused on weed management in agronomic crops. Known for his quick wit and no-nonsense attitude, Mark was a foundational part of OSU’s Agronomic Crops Team. Mark traveled all over the state delivering weed management information at field days and workshops. His ability to relate to growers and deliver information that was both educational and entertaining was admired by many of us in Extension. His research evaluating herbicide efficacy and weed management best practices led to timely recommendations for growers. Mark led the editing and production efforts for the Weed Control Guide for Ohio, Indiana, and Illinois, along with countless contributions to the CORN newsletter, fact sheets, and media features. Over the course of his career, he earned several awards including honors for outstanding papers and service to our weed science societies. Beyond his research and Extension duties, Mark was a dedicated employee and contributed a great deal of time and effort to service on various committees for the department and college,” Essman wrote in a recent CORN Newsletter. “Mark has served as my boss, academic advisor, and mentor for nearly a decade. I will miss having him just down the hall for a cup of (high quality) coffee and a chat. Lucky for me and unfortunately for him, I have his number. On behalf of the OSU weed science program, I’d like to say thank you to Mark for being our fearless leader and friend, and backpack spraying with us until the very end. We wish you the best and offer sincere congratulations on your retirement.”

Check Also

What do these weeds have in common?

By Greg LaBarge, CCA, Ohio State University Extension What do marestail, cressleaf groundsel, purple deadnettle, …

Leave a Reply

Your email address will not be published.