Texas Tech University

Graduate Student Researching Cotton Response to Herbicides to Aid in Weed-Control Battle

Amanda Bowman

November 14, 2019

(VIDEO) Delaney Foster hopes her work will improve crop sustainability and herbicide efficacy in order to protect cotton from weeds and enhance yield and profitability.

The cotton industry is vital to Texas, with the state producing approximately 35% of the United States' cotton crop, according to a 10-year average from the National Cotton Council of America. Lubbock and the South Plains has an even loftier claim to cotton: it is the largest cotton-producing area in the world. There's no doubt cotton is the cash crop that sustains West Texas communities.

But with generations of successful planting and harvesting, there's one persistent threat to cotton and crop production in general: weeds, which compete with desirable plants, such as cotton.

"Weeds decrease yield and harvest efficiency," said Delaney Foster, a Texas Tech University graduate student working on her master's degree in plant and soil science through the College of Agricultural Sciences & Natural Resources. "They compete with our crops for light, nutrients and water, and water is our most precious and limited resource needed to grow crops. Weeds are prolific seed producers, which means we will be fighting them for years to come if not effectively controlled. They've adapted the ability to survive, and they are resilient plants."

Battling weeds

Chemicals known as herbicides were developed in the late 1800s to help combat weeds, with newer forms, dubbed "miracle" weed-killers, hitting their stride in the late 1940s. Herbicides today are applied at lower use rates and are less toxic to mammals. But too much of a good thing turned bad and, eventually, weeds became resistant to some of the most effective herbicides.

Delaney Foster
Delaney Foster

To fight herbicide resistance, Foster is working on research led by Peter Dotray, the Rockwell Chair of Weed Science in the Department of Plant and Soil Science with a joint appointment with the Texas A&M Agrilife Research & Extension Service in Lubbock.

Foster is looking at the herbicide isoxaflutole in HPPD-tolerant cotton. HPPD, which stands for P-hydroxyphenylpyruvate dioxygenase, is an enzyme inhibited by isoxaflutole. Foster is testing how HPPD-tolerant cotton responds to isoxaflutole applied pre- and post-emergence and looking at the efficacy of this herbicide to control weeds.

"Isoxaflutole is an effective herbicide used in corn that prevents weeds from coming up through the soil, and may be another tool cotton growers will be able to use in the near future," Foster said.

Tracking progress

Foster established several cotton studies in 2019 in replicated small-plot research trials and is carefully documenting the results.

"When we go out to a research field, we mark off four-row-by-30-foot plots and make precision applications using a small plot tractor-mounted sprayer or use a CO2-pressurized backpack sprayer," Foster said. "Then, we'll come back and evaluate weed control and crop response visually or quantitatively."

Foster and others
Foster and others conducting research.

The hope is that the herbicide Foster is working with will help increase crop resiliency, sustain the longevity of herbicide effectiveness and help grower profitability.

"This research matters to farmers because, for one, they don't want their cotton injured by herbicides; they want herbicides to be safe," Foster said. "They also want them to be efficacious; they want them to work really, really well. So our research is basically looking at how well this herbicide will work and how we can best recommend it to farmers once it is available."

Why research herbicides?

One thing that drew Foster to Dotray's research project was the focus on practical long-term solutions that help growers manage weeds.

"I had the option to choose between a lot of different research topics at Texas Tech with Dr. Dotray, and this one was just the most interesting because it involves a systems approach that uses a new cotton herbicide to control troublesome herbicide-resistant weeds," Foster said. "This herbicide and this new cotton technology actually isn't on the market yet. It's not set to be released until about 2023, so it's still in the early experimental stages.

"I worked on experimental products in my undergraduate research at the University of Georgia and with Syngenta, so it really interested me to keep that focus. Our goal is to better understand how this new technology can best be used when it is released."

Explaining isoxaflutole and HPPD to others

Part of the challenge when conducting research is explaining to others outside of your area of expertise exactly what you're doing and why they should care. To help graduate students think more comprehensively about their work, the Texas Tech Graduate School hosts a Three Minute Thesis (3MT®) competition.

3MT® challenges master's and doctoral students to summarize and explain their research in three minutes or less in language appropriate to a non-specialist audience using only one, static PowerPoint slide.

Foster decided to take her work to task and competed in this year's 3MT®. She noted how difficult, yet rewarding, it was.

"It was one of the harder graduate contests I've ever competed in," Foster said. "Being able to take your research and really cut it down to three minutes and make it so that anyone, not just in the agriculture or plant soil science industries, can understand it was really, really difficult. I don't ever think about defining a weed because everyone in my industry knows what a weed is. But the general public might not actually understand just how bad weeds are and how much they hurt crop yields. Being able to explain that was definitely really difficult, and I had to take a step back and prepare for that."

Foster managed to overcome any difficulties explaining her research. She not only came in first place in the competition, but she also was selected as the People's Choice winner.

"It was a great feeling, knowing that everyone in the room, people who weren't in my profession or plant and soil science or even in agriculture, in general, were really interested in what I was doing," Foster said. "To me, that's what winning the People's Choice award meant – people were really interested in my research. They really understood it by my Three-Minute Thesis presentation, so that was really awesome not only to be selected by the judges but also by the general audience.

"It's just a really good opportunity, whether it is enhancing your public speaking, because that's always something graduate students should try to strive to do, or just be able to convey your research to a broad audience. That's something that, when people ask me what I do, it's hard for me to put it into layman's terms and really explain to them why my research is important. So, it was a great exercise and a really fast-paced competition because three minutes isn't a lot of time."