Stripe Rust Remains at Very Low Levels

Dr. Xianming Chen, USDA-ARS Plant Pathologist, released his most recent Stripe Rust Update, April 18, 2019. The late winter snow cover and low temperatures combined to reduce overwintering survival of the stripe rust pathogen. Stripe rust was not detected in any commercial fields in his survey of Adams, Benton, Douglas, Franklin, Grant, Lincoln, Walla Walla, and Whitman Counties, WA, including the field in Grant County where stripe rust was found in Fall 2018.  The only stripe rust spotted in this survey was in an experimental plot near Walla Walla, where a few leaves near the soil surface had actively sporulating lesions. The late appearance of stripe rust relative to previous years and the very low intensity is good news for wheat growers. At this time, the benefit of fungicide application with herbicide is marginal and should only be considered in the Walla Walla area and south for moderately susceptible to susceptible varieties rated 5 to 9 in the Washington State Crop Improvement Seed Buyers Guide. Since stripe rust has yet to make an appearance north of the Walla Walla area, it’s unlikely that a fungicide with herbicide will be beneficial.

This is perhaps the lowest amount of stripe rust present in the inland PNW at this time of year over the past 5-8 years. Although this update is good news, the temperatures over the past month have been unseasonably cool, which reduced rust development. With temperatures expected to increase over the coming weeks, it’s important to scout fields because stripe rust can increase rapidly under favorable conditions. Given the low incidence of rust now, consider fungicide application when 5% rust incidence or severity is found on varieties rated 5 or greater in the Seed Buyer’s Guide; fungicide application should not be needed for varieties rated 4 or less.

If you haven’t planted spring wheat yet, remember we always recommend planting the most resistant variety possible (rated 1 to 4) that performs well in your production area. You can use the Variety Selection tool or Seed Buyers Guide, both on this website, to learn more about the resistant ratings of varieties.

Check back frequently or Subscribe to Small Grains to receive an email when posts appear – we’ll have more information as it becomes available.


Stripe Rust Update April 18, 2019

Xianming Chen

Stripe Rust Found in Walla Walla Area

Yesterday, we were checking wheat fields in Whitman, Lincoln, Douglas, Grant, Adams, Franklin, Benton, and Walla Walla counties of Washington. Winter wheat crops ranged from Feekes 3 to 6. No rust was found in any commercial fields in these counties. Even in the field of Grant County in which stripe rust was found quite easily last November, stripe rust was not found, indicating that the cold winter has killed rust. However, we found stripe rust on susceptible varieties in our experimental field in Walla Walla. In this less than a half-acre field, we were able to found five separate infection sites, each with 2-4 low leaves having active stripe rust pustules (Figure 1), indicating that the plants were infected last fall and stripe rust fungus has survived the winter in this area. Compared to the last year, the appearance of stripe rust in Walla Walla is much later and in a much lower level.

Figure 1

Stripe Rust on wheat.

Wheat stripe rust found in an experimental field in Walla Walla on April 17, 2019.

The current stripe rust pressure is low. Use or not use fungicides at the time of herbicide application depends on regions. For the Walla Walla region and further south into northeastern Oregon, fungicides may be needed for fields planted with susceptible or moderately susceptible varieties (stripe rust ratings 5-9 in the Seed Buyer’s Guide), while resistant and moderately resistant varieties with ratings from 1-4 may not need fungicides. For areas further north, stripe rust may not appear until in two to three weeks and fungicide application may not be needed for any varieties in the early season. As the crop season is late and soil moisture is good this year, stripe rust may develop to damaging levels in late season and fungicide application in flag-leaf to grain filling stages may be needed for moderate susceptible and susceptible varieties. It is always a good idea to check fields and apply fungicide when stripe rust is found.

Stripe Rust in Other States

So far, wheat stripe rust has been reported in Texas, Louisiana, Mississippi, Oklahoma, Kansas, and Washington; and barley stripe rust has been reported in western Oregon. Although the current distribution is not as wide as this time of the last year, wheat stripe rust may still be able to cause localized damage. Check fields and use fungicides when needed.

Talking Heat Resilience in Wheat & Rice with Argelia Lorence

Subscribe on iTunes | Android | Stitcher | SoundCloud | SpotifyRSS feed

Show Notes & Resources Mentioned:

Contact Information:

Contact Argelia Lorence via email at alorence@astate.edu.


What is a podcast?

For those of you who are newer to the medium, a podcast is like a pre-recorded radio show. In the same way that you turn on a talk radio show, you have to turn on a podcast. The major difference is that while our cars are equipped to find radio frequencies, they are not built to accommodate direct access to podcasts. On your smartphone or computer with internet access (since the files tend to be on the larger side), you can discover podcast shows of any kind, in any field, on any topic.

Listed above are some of the most used podcast hosts. iTunes and the iTunes Podcast app are preinstalled on your iPhone and are the simplest tools to use. You simply search for “WSU Wheat Beat Podcast” in the search bar, hit “subscribe” and the download arrow, and listen whenever it’s convenient for you.

If you use an Android or use another type of smartphone, you will need to find a different podcasting app because those devices don’t come with a preinstalled app like Apple. If you don’t know which podcast app you’d like, simply hit the “Android” link above and it will show you to several Android podcast apps for you to choose from.

After you download an episode, you can listen without using data any time of day. Our goal is to post a new podcast every other Monday. Your podcast app should automatically load our new episodes and download them for you (on WiFi), hands-free if you choose that in the app settings.

If you have further questions about what a podcast is, which app is best for you or need more assistance with getting started with podcasts, don’t hesitate to contact us.


Episode Transcription:

[ Music ]

Drew Lyon: This episode of the WSU Wheat Beat podcast was recorded on March 22nd, 2019, during the WSU Plant Science Symposium. The theme of the symposium was foundations for the future, embracing new agricultural technologies. As part of the program, five innovative researchers from across the U.S. and the world agreed to speak about their research. All five researchers also agreed to sit down with me for a few minutes to explain their work, and how it may relate to wheat growers in Eastern Washington.

[ Music ]

Drew Lyon: Welcome to the first episode of our special series from the 2019 WSU Plant Science Symposium. My guest today is Dr. Argelia Lorence. Argelia is the James and Wanda Lee Vaughn Endowed Professor at Arkansas State University. The most significant contribution Dr. Lorence has made to plant sciences has been the discovery of a novel, biosynthetic pathway for vitamin C. Her laboratory uses Arabidopsis to better understand the role of various subcellular pools of vitamin c in plant physiology. In addition to Arabidopsis, her current models of study include rice, soybean, and maize. She is co-principle investigator of the wheat and rice center for heat resilience, which is an NSF funded project focused on finding novel genes, involved in conferring rice and wheat tolerance to high night temperatures. One of the key factors that limits the yields of these two most important crops in the world for food security. Hello, Argelia.

Argelia Lorence: Hello, Drew.

Drew Lyon: So, what is the wheat and rice center for heat resilience? What does it do?

Argelia Lorence: Well, we are project funded by the National Science Foundation, in particular by the EPSCoR Track-2 program. And in this program, the rules of the game are you need to partner with other universities in the United States that are in what is called an EPSCoR state. EPSCoR states are the ones that comparatively speaking, get less funding than others. Let’s say the bottom half of the US states. So, Nebraska is part of that group, Kansas is as well, and Arkansas is. So, this project is a partnership between the University of Nebraska-Lincoln; Kansas State University; Arkansas State University; and Virginia Tech. And together, we’re working on finding novel ways, novel mechanisms, novel genes to confer rice and wheat tolerance to high night temperature stress. Why this stress? It’s because this is the stress that is affecting both the yield, that’s quantity, and quality of rice and wheat.

Drew Lyon: Okay, and nighttime heat versus just heat in general, daytime heat.

Argelia Lorence: Yes, so there have been previous studies. You know, in science we always build on someone else’s work, right?. I mean, we stand on the, basically on the shoulders of giants. So, previous studies have shown that if you stress either rice or wheat during the day, versus if you stress them with heat during the night, the one that causes the most penalty is the night temperature. In rice, there are these fabulous statistics: for everyone one-degree Celsius increase in average night temperature, there is a 10% penalty in yield. Imagine that. So, the Currant Climate Change Center has predicted a 3.7 increase in Celsius. So that is 40% penalty in yield.

Drew Lyon: And, correct if I’m wrong about this, but I think one of the things also predicted is that it’ll be, maybe not your daytime temperatures getting that much hotter, but that your nighttime temperatures won’t get as low as they normally do.

Argelia Lorence: Yes. Yes.

Drew Lyon: So that’s even a bigger challenge if this nighttime heat that’s causing us problems.

Argelia Lorence: Absolutely. So, in this project, we want to get ahead of the curve and before those changes happen, we want to identify already what natural variance in both rice and wheat have these tolerance, right? And for that, we are exploring what is called diversity panels. They are, it’s a collection basically of different cultivars that come from all over different, at least the one in rice, many, many different regions of the world. Because we’re trying to; rice is divided into five major subgroups, so in this panel that we’re using, we have representatives of all five sources. And for the wheat part of the project, we are exploring winter wheat which is grown in Kansas mostly, right? Because again, this is a partnership with that state, which is the main wheat producer in the US. So, I guess, it’s important to say the reason why this partnership makes a lot of sense is because Kansas is the main producer of wheat in the U.S., Arkansas is the main producer of rice in the U.S., and we’re partnering, and Nebraska brings great things onto the table because they have this beautiful phenotyping facility at the University of Nebraska-Lincoln. So, they are the ones analyzing in a lot of detail all these 400 different types of rice, and all these 400 different types of wheat. And they have also a lot of expertise, so the leader of the overall project is Dr. Harkamal Walia. He’s at the University of Nebraska-Lincoln. And he has put a great team together there in Nebraska where he has, well, he’s crop physiologist, but there are also computational scientists at these stations. Systems biology experts, experts in analyzing image analysis. So, basically, there is a lot of expertise being integrated into the project. It’s one of the most exciting things. I have these super, super interesting collaborators that are experts in many different things, so collectively, we make the project better.

Drew Lyon: Okay, yeah, that sounds like a very broad group. What does Virginia Tech bring to the program?

Argelia Lorence: Yes, so let me tell you how Virginia Tech got engaged. So, Virginia Tech hired Dr. Gota Morota. He is an outstanding quantitative geneticist. He used to work at the University of Nebraska-Lincoln, but he got hired by Virginia Tech, so. So, we are very lucky that instead of losing him, we get to keep him involved in the project, although physically, now located at Virginia Tech.

Drew Lyon: So, it sounds like this project should generate a lot of new information. Scientists like to publish in refereed journal articles, that’s kind of our coin of the realm so to speak. But, how else are you going to find the findings from this project both to breeders who might use it, and farmers who might want to use it in their operations?

Argelia Lorence: Well, thank you for asking me that question, it’s an excellent one. So, we are taking really all possible avenues to communicate our findings. We have a project website, we have a project Facebook account, we have a project Twitter account, and then we participate in what is called Farmer’s Days, right? So, there is a Rice Day. So, something that I should add is in Arkansas, we are doing all of the field work, in an experimental station that is owned by a company called Rice Tech. They are the main producers of hybrid rice seed in the U.S. And they have this excellent experimental station, very close to the university where I work. So, instead of just doing the work in the university farm, we are doing the experiments in a real state-of-the-art farm.

Drew Lyon: That’s a nice thing to have.

Argelia Lorence: Yes. So, Rice Tech, for example, they have a field day, it’s like a showcase day, and they’re going to allow us to be part of that where they usually bring, like, several hundred of rice farmers, right? So, it’s going to be on August 6th this year, so August 6th, we’re already scheduled to be on the field day for Rice Tech and show to several hundred farmers in Arkansas what we’re all about. So, we are also the project, well, in Arkansas rice is a $6 billion industry. So, it’s the main breadwinner there. So, there is a lot of interest from the rice farmers. I think because of that, recently both radio, the local radio station, the local newspapers, called the Jonesboro Sun, and also the local TV station have come, have approached us, interviews, to, it’s like, what are you guys about? What is all of this hype about rice? What exactly are you doing in rice? Because it’s important, it’s the livelihood of many, many people.

Drew Lyon: So, you mentioned a webpage, could you tell us what the URL for that webpage is?

Argelia Lorence: Absolutely. So, we call ourselves the Wheat and Rice Center for Heat Resilience. So, if you just use the first letter of one of those, right: WRCHR; Richer, right? WRCHR.org. So, that’s our website. And we have a Facebook page, we’re very easy to find, and also a Twitter page.

Drew Lyon: Okay. So, you want to give us that URL one more time?

Argelia Lorence: Yes. WRCHR.org.

Drew Lyon: Alright. So, if somebody is interested in that, they can go look at that.

Argelia Lorence: Yes.

Drew Lyon: So, we don’t grow, to my knowledge, any rice in Washington, but we grow a whole lot of wheat. So, what do you see as, how what you’re doing will have an impact on our wheat farmers here in the state of Washington?

Argelia Lorence: Yes, so I can, another great question. As I said, we’re funded by the National Science Foundation, right? So, this is your tax dollars and my tax dollars being used. So, of course, we’re going to generate information, and then disseminate the information widely so that breeding programs all over the U.S. that involve either wheat or rice can benefit from this work, right?

Drew Lyon: Okay.

Argelia Lorence: And thinking as citizens of the world, I mean, one of the things you observe in the composition of our team is we are from all over, right? I’m from Mexico, Dr. Walia is from India, Dr. Jagadish is from India, Dr. Morota is from Japan, Dr. Arlene Adviento-Borbe, one of the person’s really leading all of the field work in Arkansas, is from the Philippines. So, we are really from all over the place. Of course, we have also U.S. faculty involved. So, we want this to benefit as many people as possible, right? So, I mean, we want ultimately for food security units think global, right? I mean, this is the one planet we all share, and these are the two main crops or two of the main crops.

Drew Lyon: I was just going to say, these are two very important crops.

Argelia Lorence: These are two very important crops, so we want to benefit as many people as possible with the project. So, I see, again, we are going to make every attempt in disseminating the information as widely as possible, and of course, it impacts the wheat farmers in Washington, yes.

Drew Lyon: Good. So, I think this is another example of taking more basic science and translating into applied fields, and we should see the fruits of this down the road, which are going to be important to us as our world gets warmer and carbon-dioxide levels go up.

Argelia Lorence: Yes.

Drew Lyon: I appreciate you taking some time to visit with us, today.

Argelia Lorence: This is fantastic. I should mention, we are funded for four years, and this is our second year.

Drew Lyon: Okay.

Argelia Lorence: So, the best is still to come.

Drew Lyon: Alright, excellent. Well, we’ll look forward to seeing more things coming out of the program. Thank you very much for your time, I really appreciate it.

Argelia Lorence: Thank you so much.

[ Music ]

Drew Lyon: Thanks for joining us and listening to the WSU Wheat Beat podcast. If you like what you hear don’t forget to subscribe and leave a review on iTunes or your favorite podcasting app. If you have questions or topics, you’d like to hear on future episodes please email me at drew.lyon That’s lyon@wsu.edu (drew.lyon@wsu.edu). You can find us online at smallgrains.wsu.edu and on Facebook and Twitter @WSUSmallGrains. The WSU Wheat Beat podcast is a production of CAHNRS Communications and the College of Agricultural, Human and Natural Resource Sciences at Washington State University. I’m Drew Lyon, we’ll see you next time.

EPA Releases Residual Time to 25% Bee Mortality (RT25) Data Reducing Pesticide Hazards for Bees

You have likely heard in the recent past that honey bee (Apis mellifera) and wild bee populations across North America and other parts of the world are in decline. A number of factors are responsible for these declines, including the use of insecticides, parasites like the Varroa mite (Varroa destructor), pathogens, and a lack of suitable habitat.

Research shows insecticides like neonicotinoids and pyrethroids, which can be found in over-the-counter products, can negatively affect bees. However, these effects can be mitigated when pesticide sprays are timed to avoid key periods when bees pollinate crops. Thus, it is important to be aware when bees or other pollinating insects like flies or butterflies are foraging for pollen and nectar. While cereal crops do not provide nectar rewards for bees and are rarely visited, weedy species that produce flowers can attract bees. Canola and mustard crops, as well as some legumes, are also attractive to bees.

There are several important precautions that can be taken if insecticides need to be applied to crop plants or weeds. The following list of precautions comes from Washington State University Extension Fact Sheet FS147E Pollination and Protecting Bees and Other Pollinators (pdf):

  • Avoid spraying whenever bees are or might be flying. It can be difficult to see some bees on some types of flowers. Additional precautions should be used when using pesticides where flowers are present.
  • Try to spray before bloom or after the flowers are done blooming.
  • Look for other flowers that may be blooming nearby or on the ground below the tree or bush to be sprayed. Look around for other flowering bushes or trees where the pesticide may drift.
  • Try not to spray just before or during bloom, but if it is necessary, try to spray at night or very early in the morning, before the bees are flying. Once the spray has dried on the plant, it may be less toxic to bees.
  • Avoid spraying if there is heavy fog or dew, as this will keep the pesticide wet and will increase the chance of the bees receiving a toxic dose.
While we know that direct applications of certain pesticides to foraging honey bees can be detrimental, it is also important to note that certain insecticide residuals can also pose a threat to bees. The EPA recently released a study looking at the “residual time” i.e. amount of time that pesticide residues on plants are still considered lethal, that is required to kill 25% of a population. An explanation of the study and its result can be found at Pollinator Protection: Residual Time to 25% Bee Mortality (RT25) Data.

It is always important to carefully read and follow all pesticide label instructions and to be aware of pollinating insects and other beneficial arthropods that may be present during or after a pesticide application.


For questions or comments, contact Dale Whaley via email dwhaley@wsu.edu or contact Dave Crowder at dcrowder@wsu.edu.

Cereal Grass Aphid (Metopolophium festucae cerealium) in the Pacific Northwest

A guest post by Sanford Eigenbrode, University of Idaho. University of Idaho logo.


Several years ago, we detected and reported the presence of a new aphid in wheat, Metopolophium festucae cerealium, which we are currently calling “Mfc” or “Cereal grass aphid”. A known pest of cereal crops in its native range in the UK, it was initially detected in Oregon in the 1990s but rather suddenly became abundant in Washington state, northern Oregon, and northern Idaho by 2011. It continues to be one of the most abundant aphids in wheat at many locations in the inland Pacific Northwest. Recently, isolated specimens of this pest have been detected in southern Idaho, Montana, and Kansas, suggesting it is spreading. Based on a greenhouse experiment with wheat seedlings, feeding of this pest induces a distinctive chlorotic reaction in wheat and other hosts, presumably causing more per capita injury than by other cereal aphids in the region. Cereal grass aphids established from a clonal colony in the greenhouse was unable to transmit Barley yellow dwarf virus. However, other genotypes of this aphid with other strains and isolates of Barley yellow dwarf virus may result in transmission, which requires further studies. In other words, Cereal grass aphid is persisting in our systems and may be spreading so we should pursue additional research to establish whether it is a virus vector and to build appropriate decision support tools for its management.

Figure 1.

Small colony of cereal grass aphids.
A small colony of cereal grass aphid showing the typical injury it cases to wheat (photo by B. Palmer, McGregor Corp. taken near Colfax, Washington, June 2015).
A winged aphid.
An alate (winged) adult aphid (photo by T. Murphy).
Recently, we participated in the Entomological Society of America Grant challenge to crowd-fund some work to determine the occurrence, abundance, and impacts of Cereal grass aphid in North America in annual cereal crops and in natural and semi-natural grassland habitats across the region and to communicate this information to the public to help citizens and producers who respond to the presence of this aphid. We are also seeking federal funding to expand the research on Cereal grass aphid.

Meanwhile, growers should be vigilant for the pest in their wheat fields. The characteristic feeding damage occurring with groups of pale green aphids as shown in Fig. 1 indicates a likely infestation. If you see those signs in either spring or winter wheat this season, please let us know. There is as yet no threshold, but based on one greenhouse trial its effects on plant growth are greater than most other aphids in our system.


A Partnership: UAVs and Wheat Breeding with Arron Carter and Lav Khot

Subscribe on iTunes | Android | Stitcher | SoundCloud | SpotifyRSS feed

Show Notes & Resources Mentioned:

Contact Information:

Contact Arron Carter via email at ahcarter@wsu.edu. Contact Lav Khot via email at lav.khot@wsu.edu.


What is a podcast?

For those of you who are newer to the medium, a podcast is like a pre-recorded radio show. In the same way that you turn on a talk radio show, you have to turn on a podcast. The major difference is that while our cars are equipped to find radio frequencies, they are not built to accommodate direct access to podcasts. On your smartphone or computer with internet access (since the files tend to be on the larger side), you can discover podcast shows of any kind, in any field, on any topic.

Listed above are some of the most used podcast hosts. iTunes and the iTunes Podcast app are preinstalled on your iPhone and are the simplest tools to use. You simply search for “WSU Wheat Beat Podcast” in the search bar, hit “subscribe” and the download arrow, and listen whenever it’s convenient for you.

If you use an Android or use another type of smartphone, you will need to find a different podcasting app because those devices don’t come with a preinstalled app like Apple. If you don’t know which podcast app you’d like, simply hit the “Android” link above and it will show you to several Android podcast apps for you to choose from.

After you download an episode, you can listen without using data any time of day. Our goal is to post a new podcast every other Monday. Your podcast app should automatically load our new episodes and download them for you (on WiFi), hands-free if you choose that in the app settings.

If you have further questions about what a podcast is, which app is best for you or need more assistance with getting started with podcasts, don’t hesitate to contact us.


Episode Transcription:

[ Music ]

Drew Lyon: Hello. Welcome to the WSU Wheat Beat podcast. I’m your host, Drew Lyon, and I want to thank you for joining me as we explore the world of small grains production and research at Washington State University. In each episode, I speak with researchers WSU and the USDA-ARS to provide you with insights into the latest research on wheat and barley production. If you enjoy the WSU Wheat Beat podcast do us a favor and subscribe on iTunes or your favorite podcasting app and leave us a review while you’re there so others can find the show too.

[ Music ]

Drew Lyon: My guests today are Dr. Lav Khot and Dr. Arron Carter. Dr. Khot is an Assistant Professor in the Department of Biological Systems Engineering at Washington State University, he’s one of the core faculty members of the Center for Precision and Automated Agricultural System and works in the Agricultural Automation Engineering Research emphasis are of the department. His research and extension program at WSU focuses on sensing and automation technologies for site-specific and precision management of production agriculture. Hello Lav.

Lav Khot: Hello.

Drew Lyon: Dr. Carter is an Associate Professor and O.A. Vogel Endowed Chair of Wheat Breeding and Genetics in the Department of Crop and Soil Sciences at Washington State University. His research is directed toward breeding improved winter wheat varieties for cropping systems in Washington State that incorporate diverse rotations and environments. The program goal is to release high yielding disease resistant varieties with good end-use quality that will maintain profitability and reduce the risk to growers. Varieties are developed using a combination of traditional plant breeding methods, molecular marker technology, biotechnology, and High Throughput Phenotyping. Hello Arron.

Arron Carter: Hi, Drew, how are you today?

Drew Lyon: Pretty good. So I was wondering, how did the two groups, two different departments, two areas of expertise, how did the two of you come together to work on the projects you’re working on?

Arron Carter: Yeah, I think it started a little bit with me. So we had had some projects going with High Throughput Phenotyping, basically using some handheld sensors and when Lav got here, you know, with his expertise in more of the engineering side and the sensors development I approached him and told him kind of about some of the projects that we had going on and where I thought I could use his expertise in those projects, so I think I got him a little excited about that and some of the possibilities and, you know after that, we just started working on projects and kind of had that continued collaboration ever since.

Drew Lyon: Okay. Yeah, so it’s just a visit from Arron, he was convincing enough that he that you decided to go work in that area, what attracted to the areas he was…

Lav Khot: Yeah so, very simply, we had this drone or small aerial systems emerging and when I had a meeting with Arron, and he told me some of the problems that we can look at using this technology, and that’s what, you know, basically problem and technology coming together is what happened.

Drew Lyon: Okay.

Lav Khot: Yeah.

Drew Lyon: So tell us a little about the drone sensing work that the two of you did on wheat emergence.

Lav Khot: Sure. What we did is, you know, at the time we had these small unmanned aerial system platform and at that time, it was just emerging technologies, so we didn’t have many of these optical sensors that we have today, but what we had is a point and shoot camera, basically, RGB, I wanted to get NDVI or green NDVI basically, and so we wanted to, you know, see how useful that sensor is with drone missions to look at crop emergence and winter wheat, looking at the winter survival, spring stand and potentially look at the yield estimation aspects a little bit and most of the work that we did was on corporate that Arron had in Lind and…

Arron and Lav: Colotis.

Arron Carter: Yeah, so we kind of started out with some of the easier traits to look at with the, you know, the system, and then as the systems have become more complex and we’ve got better sensors and better devices, we’ve moved to then some of the more complex.

Drew Lyon: Okay.

Arron Carter: Traits to look at, but yeah, for proof of concept, start of easy to see if it works.

Drew Lyon: So emergence would be something that’s easy it’s there, it’s not —

Arron Carter: Right, right.

Drew Lyon: And now, what are some of the more complex things that you’re looking at?

Arron Carter: Yeah, you know, at least in wheat, we’re starting to look at drought, so water use efficiency in the plant and how that water use actually gets converted to yield potential. Also starting to look at some disease resistance screening and can we actually get accurate notes, potentially even earlier than you can actually visually see the symptoms with some of the sensors.

Drew Lyon: Okay. So where can people use remote sensing and wheat production these days? I know you do a lot of work in the tree fruit area.

Lav Khot: Sure.

Drew Lyon: Very high-value crops.

Lav Khot: Yeah.

Drew Lyon: But what are some of the ideas you have for wide, broadacre crop like wheat?

Lav Khot: Well, as Arron mentioned, you know, we have to look at these traits through water, climate, maybe and then some of the disease aspects, right? So in terms of technology, you can use simply a thermally reading sensor and get the aspects of water stress, you know, in thermally reading you do, you measure with each pixel and image is a temperature.

Drew Lyon: Okay.

Lav Khot: So you can use such image in there. In terms of going for the disease traits, I think you need to be more complex sensors, you know, like, the sensors that are out in the market multispectral, they can do, like oral signature, but they won’t tell you what is causing the stress.

Drew Lyon: Okay.

Lav Khot: And so you care to go for disease and you care to go for hyperspectral sensing and the sensors are there, simply cannot be flown with the drones, as of now.

Drew Lyon: Okay.

Lav Khot: So we had to do ground research and then find these bands, multispectral bands and then how the sensors deals with for screening certain disease, specific disease. And that’s where I think we need to go in terms of normal screening, like, looking at the stress, just not knowing which stress, but stress, besides, you know, drone, as a remote sensing tool, there’s a lot of developments of which is called orbiting Satellites, so now these low orbiting Satellites are giving you an image ever other day at points of one centimeter resolution. So you can use, you know, we have a have high orbiting Satellite’s giving thirty meters per pixel every fourteen days, then we have low orbiting giving .723 or five meter resolution and then use drones, so use layers of information in terms of production management.

Drew Lyon: Okay.

Lav Khot: That’s where the, you know, the remote sensing is as of today, yeah.

Drew Lyon: Okay. I know as a weed scientist, the idea of figuring out what kind of weed pressure you might have will be of real interest and is it, you know, is it worthwhile to go out there and spray the whole field…

Lav Khot: Sure.

Drew Lyon: …or just have a little area I should deal with?

Lav Khot: Yeah, yeah,

Drew Lyon: And so that technology would work for something like that as well?

Lav Khot: Yes, and then you can do the remote sensing; again, there are unmanned aerial system platforms that also do surgical spraying.

Drew Lyon: Oh, really?

Lav Khot: Yeah, and so we, you know, there’s a company in Seattle they make certain types of drones and there are other players. So you can use these drones, map the field and how the GPS guide the coordinated points to go and just activates the nozzles to only spray on that spot, so it’s surgical spraying or spot spraying can be done with the drones, yeah.

Arron Carter: Is what I found, Drew, is sometimes it’s only limited by your imagination.

Lav Khot: True.

Drew Lyon: That’s just amazing.

Arron Carter: I mean, yeah, a lot of — we can do a lot different things with the systems like you mentioned, you know, looking at weed pressure, just looking at overall health of the crop across the field, you can start mapping out, you know, nutrient deficiencies in the field, I mean, again, it’s really only limited by what we can think of using the technology for.

Drew Lyon: Okay. So does WSU offer any training or workshop on drones or data analytics? I know there’s a lot of interest out there, but it’s a little more complicated than just going and buying a drone and throwing it up in the air.

Lav Khot: Yes. True. Yeah. Well, nowadays, you know, buying a flying a drone is very easy, to be honest, right? Compared to what we had in 2015 or 2016. Yes, and in terms of workshops, we do offer, in my program, at CPAAS, we have two workshops that are offered annually. The first one is a two day workshop on Manual Systems and Agriculture; so in two days what we do is, we take different types of drone platforms that we have in the market, we just go through all of the parts of the drone, how they come together, how they integrate, inputting optical sensors and basically, the idea is not to, you know, teach you how to build a drone, but if something goes wrong on the drone you should be able to at least figure out which part has gone wrong and you should be able to replace it. Then we do hands-on training on how to fly a drone with the optical that is there, we also do what is called Part 107 that is the regression, in terms of getting the drone pilot certification to fly the drones commercially, so that’s what this two day workshop coheres and we have in the last two years have had a very good response to this workshop. The second one is just a one day workshop, it’s called Drone Data Analytics and this is more popular than the two-day workshop because a lot of people are interested in the data side of the drones.

Drew Lyon: Okay.

Lav Khot: And so we do this with the help of Pix4D company based in San Francisco, it draws a very simplified software to analyze the drone data to create layers of information. There’s another player that is there is MicaSense Sensor Company which deals with multispectral sensors based in Seattle and so the instructors come from there, and me, we do this for one day we just hands-on training on how to, you know, collect quality data, look at the quality of the data, and then analyze the data to create layers of information, that’s what we do in one day, yeah.

Drew Lyon: Okay. Very good and how would people find out about that? Is that up on a website somewhere?

Lav Khot: Yeah so yeah, we do have on CPASS website that is there, and once we finalize the dates we just try to promote WSU extension and other venues.

Drew Lyon: Okay.

Lav Khot: So that it goes to all stakeholders to if they’re interested that can come join us at CPAAS, yeah.

Drew Lyon: Okay. So is there a web address for CPAAS?

Lav Khot: Yeah, sure. There’s of course, my web page is there, but its part of the CPAAS website it is at: Www.CPAAS.WSU.EDU.

Drew Lyon: Okay. And, Arron, some of this data that you’ve been collecting now, do you see, you know, I know when we look at when you’re selecting a variety what it’s disease rating is, what it’s do you see some kind of new data point that you’d be providing growers? Drought, some kind of drought tolerance, or how do you see using it in the information that you share with growers, I guess, is what I’m asking.

Arron Carter: Right. Yeah, you know, so on the breeding side of it, you know, it can help us do the selections for disease resistance and that, I don’t know if that would necessarily transfer to a different grower rating, right?

Drew Lyon: Okay.

Arron Carter: So either going to be susceptible or resistant. We might be able to understand a little more though about how, maybe the plants grow or recover from the disease. You know, if you think of something like snow mold, a lot of that tolerance is about regrowing in the spring time, and not necessarily a true resistance. So these sensors, we can actually watch the plants growing over time and see which ones regrow faster than another one, so that gives a little more understanding. I think more importantly, would be like on drought or heat stress where we could actually give ratings to different varieties of how well they can withstand drought, how well they could withstand heat; so, you know, it kind of works in different ways, depending on what we’re looking at.

Drew Lyon: It’s really very interesting technology and like you said, but it’s only limited by our imagination these days and it’s, it’s pretty remarkable and neat to see the collaboration between the two of you, I think that’s really what’s going to move the ball forward is collaborations between disciplines so, thank you very much for your time.

Arron Carter: Yup. Thank you.

Lav Khot: Thank you.

[ Music ]

Drew Lyon: Thanks for joining us and listening to the WSU Wheat Beat podcast. If you like what you hear don’t forget to subscribe and leave a review on iTunes or your favorite podcasting app. If you have questions or topics, you’d like to hear on future episodes please email me at drew.lyon That’s lyon@wsu.edu (drew.lyon@wsu.edu). You can find us online at smallgrains.wsu.edu and on Facebook and Twitter @WSUSmallGrains. The WSU Wheat Beat podcast is a production of CAHNRS Communications and the College of Agricultural, Human and Natural Resource Sciences at Washington State University. I’m Drew Lyon, we’ll see you next time.

No Shortcuts on Green Bridge Management for Soilborne Diseases

The long, late winter is finally giving way to spring and with that comes field work and the reality of dealing with a compressed field season.  Because of that, some are thinking how to get the most done in the shortest amount of time, so they can still make a timely seeding of their spring crop.  I recently had a question about herbicide choice for the green bridge and how long to wait before planting; specifically, whether spraying paraquat to get a quick burn-down would shorten the green bridge compared to spraying glyphosate.  Our recommendation for green bridge management is to wait a minimum of 2 weeks after spraying before planting.

As a reminder, the “green bridge” is that time after spraying weeds and volunteer cereals when plants are still alive and able to serve as a bridge to carry soilborne plant pathogens to the next host plant.  The soilborne fungi that cause Rhizoctonia root rot and Pythium root rot can build-up on roots of volunteers as they are dying (technically, increased inoculum potential), so it’s critical to allow enough time after spraying for the roots to die, otherwise you will end up with severe disease when Rhizoctonia and Pythium hop onto the new seedling roots.

Back to the original question: Does this recommendation change if paraquat is sprayed instead of glyphosate?  The short answer is NO, you still need to wait at least 2 weeks before planting.  To get the details on why, I consulted Dr. Tim Paulitz, our USDA-ARS expert on these root diseases, and Dr. Drew Lyon, our resident herbicide expert.  Paulitz told me there are no data to support a recommendation on paraquat because the research has been done only with glyphosate.  Even though there are no data on paraquat, he wouldn’t change that recommendation because of the way these two herbicides work to kill plants.  Lyon confirmed that when sprayed on a plant exposed to light, paraquat acts as a powerful oxidizer that generates reactive oxygen species and quickly destroys living cells of the foliage first, with roots dying later.  In contrast, glyphosate is translocated to roots where it inhibits the shikimic acid pathway, which is involved in plant defense.  Pathogens like Rhizoctonia and Pythium are then able to more easily colonize and kill roots before the foliage dies.  The result with both herbicides is that roots survive long enough to serve as a green bridge for a couple of weeks.  So, although it’s tempting to spray and plant as soon as possible, it’s better to wait a couple of weeks before planting that spring crop after spraying weeds and volunteers, regardless of which herbicide is used.


Stripe Rust Forecast and Update, March 22, 2019

Xianming Chen

Stripe rust will be likely low this year in the eastern Pacific Northwest

This unusual winter appears over, and spring comes late but suddenly. Based on the forecast models, we predict that stripe rust will potentially cause yield loss of 16% on highly susceptible varieties. This level is much lower than the 38% forecasted in January, due to the cold February. Based on the current forecast, stripe rust will likely be in the low epidemic range (0-20% yield loss). According to this prediction, the most “susceptible” commercially grown varieties, such as Xerpha, Eltan, SY 107, and Keldin, will likely to have up to 8% yield losses, which may need fungicide application, while the majority of varieties that are rated 1 to 4 may not need fungicides.

No stripe rust was found in the field survey yesterday

Yesterday, we were checking wheat fields in Garfield, Columbia, Walla Walla, Benton, Franklin, Grant, Lincoln, and Adams counties. Thanks to the warm weather this week, most fields come out from snow. Wheat plants range from Feekes 1 to 5, but has not re-grown yet (Figure 1). The snow cover from the second week of February to last week protected wheat plants from winter kill. Winter injure was found only spotted and mostly on leaf tips. Spotted snow mold and wireworm damage were found in Horse Heaven Hills of Benton County and Grant County. No stripe rust was found in any of the checked fields, probably due to the relatively low infection in the last fall. Stripe rust fungus that got into leaf tissues last fall should have survived the coldest February but under the protection of snow cover.

Figure 1.

Figure 1. Wheat fields in Columbia (A), Walla Walla (B), Benton (C), and Grant (D) counties of Washington State, March 22, 2019.

Stripe rust in the country

So far, stripe rust of wheat has been reported in Texas and Louisiana and stripe rust of barley in Corvallis, Oregon this year.

2019 First Stripe Rust Forecast and 2018 Fungicide and Variety Yield Loss Tests

January 8, 2019

Xianming Chen

A. Field survey in November 2018

On November 16, 2018, our crew was checking winter wheat fields in Whitman, Lincoln, Adams, Grant, and Douglas counties in eastern Washington and found two leaves with stripe rust (Figure 1) in only one field in Grant County near the border with Lincoln County. Wheat plants in that field were at Feekes 4. The observations indicated a relatively normal level of stripe rust infection before the winter in eastern Washington.

B. The 2019 first forecast of stripe rust for the eastern Pacific Northwest

Based on the weather conditions in November and December 2018, stripe rust in the 2019 wheat growing season will likely be in the upper normal epidemic level range (20-40% yield loss). According to the forecast models, highly susceptible winter wheat varieties would have yield loss ranging from 27 to 48% with an average of 38%. Currently grown varieties would have yield losses from 0 to 19% depending upon the level of resistance or susceptibility. If this forecast is close to the real disease level, fields grown with moderate susceptible or susceptible winter wheat varieties (stripe rust ratings 5 to 9) would need the early fungicide application at the time of herbicide application. Based on the past experience, the early prediction made in January is often close to the real situation, but not better than the prediction in March based on the entire winter weather conditions. Therefore, we will make another prediction in early March.

C. Yield losses caused by stripe rust and increases by fungicide application on wheat varieties tested in 2018

The data of stripe rust and yield differences in non-sprayed and fungicide-sprayed plots in our experimental fields near Pullman in 2018 are shown in Table 1 for winter wheat and Table 2 for spring wheat.

Of the 24 winter wheat varieties tested, including 23 commercially grown varieties and a susceptible check (‘PS 279’), 10 varieties (PS 279, Xerpha, Eltan, SY 107, Keldin, Puma, Whetstone, ARS-Crescent, UI Sparrow, and SY Ovation) had significant differences in stripe rust severity, presented as relative area under the disease progress curve (AUDPC), between their non-sprayed and sprayed treatments. The percentage of severity reduction by fungicide application in these varieties ranged from 4.4% (SY Ovation) to 93.2% (PS 279) (Table 1). Four varieties (PS 279, Xerpha, Eltan, and SY 107) had significant differences in grain test weight with increases from 3.6 lb/bu (SY 107) to 10.9 lb/bu (PS 279) by fungicide spay. Significant yield differences, ranging from 19.1 bu/A (Rosalyn) to 69.6% (PS 279) were observed for 10 varieties (PS 279, Xerpha, Eltan, SY 107, Keldin, ARS-Crescent, Whetstone, Westbred 528, LCS Jet, and Rosalyn). Stripe rust caused 70.5% yield loss on the susceptible check (PS 279) and from 0 to 40.7% yield losses (average 10.1%) on commercially grown varieties. Fungicide application increased grain yield by 0 to 40.2% (average 12.4%) on commercially grown varieties. Under such a severe level of stripe rust epidemic, 6 commercially grown varieties (Xerpha, Eltan, SY 107, Keldin, ARS-Crescent, and Whetstone) received fungicide application rating 2, which needs fungicide application. Six varieties (Westbred 528, LCS Jet, ORCF 102, Rosalyn, Otto, and UI Sparrow) were rated 1 for fungicide application, which may or may not need fungicide application. The remaining 11 varieties (SY Ovation, Bobtail, Puma, Jasper, Legion, Madsen, Skiles, Bruehl, Cara, Farnum, and Norwest 553) received fungicide application rating 0, which does not need fungicide application.

Similarly, of the 24 spring wheat varieties tested including 23 commercially grown varieties and one susceptible check (‘AvS’), 19 varieties had significant differences and 5 varieties (Seahawk, Dayn, WB9518, JD, and WB6121) had no significant differences in stripe rust severity (presented as relative AUDPC) (Table 2). Eight varieties (AvS, Babe, WB6341, WB-1035CL+, SY605CL, Kelse, Whit, and Louise) had significant differences in grain test weight. Grain yield losses of sprayed and non-sprayed plots were significantly different for nine commercially grown varieties (Babe, WB6341, WB-1035CL+, SY605CL, Kelse, Whit, Louise, Solano, and Tekoa) in addition to the susceptible check (AvS). Stripe rust caused 66% yield loss on the susceptible check and from 0 to 47.5% (average 13.8%) yield losses on commercially grown varieties. Fungicide application increased grain yields by 0 to 90.6% (average 20.1%) on commercially grown varieties. Nine varieties (AvS, Babe, WB6341, WB-1035CL+, SY605CL, Kelse, Whit, Louise, and Solano) received fungicide application ratings 2 to 5, which need fungicide application. Six varieties (Tekoa, Alum, Glee, Buck Pronto, and Melba) received rating 1, which may or may not need fungicide application. The remaining ten varieties (SY Steelhead, SY Selway, Seahawk, Dayn, Express, Diva, Chet, WB9518, JD, and WB6121) received rating 0, which does not need fungicide application under the rust pressure in 2018.

The data can be used to select stripe rust resistant varieties to plant and to determine if fungicide application is needed for a variety based on its relative yield loss and potential epidemic level. Based on the current forecasted epidemic level (38% yield loss on susceptible varieties) for 2019 (see above), fungicide application would be needed for the varieties with a fungicide application rating 2 or higher, or stripe rust ratings 5-9 as mentioned above. Varieties with fungicide application ratings 0 and 1, or stripe rust ratings 1 to 4 in the Seed Buyer’s Guide, would not need fungicide application in 2019.

D. Fungicide tests in 2018

In 2018, a total of 31 fungicide treatments, plus a non-treated check, were evaluated for stripe rust control efficacy on both winter wheat and spring wheat in fields near Pullman, Washington under natural infection of stripe rust.

In the winter wheat field, stripe rust from natural infection started developing in the plots in early May when plants were at the early jointing stage (Feekes 5) and reached 100% severity in middle Jun at the milk stage, in the non-treated check plots (Table 3). All fungicide treatments, except one (treatment 16), significantly reduced relative AUDPC, an overall measurement of rust

severity, compared to the non-treated check. However, all treatment with only the early (Feekes 5) application did not completely stop rust development as severity reached 100%, the same as the non-treated check, at the milk stage. The treatments with only the late (Feekes 8) application produced the better control results than those of only early application. The best reduction of stripe rust was provided by treatments 5 (Quilt Xcel 7.0 at Feekes 5 followed by Trivapro 13.7 fl oz/A at Feekes 8), 13 (Topguard EQ 7.0 fl oz/A at Feekes 5 followed by Topguard 7.0 fl oz/A at Feekes 8), and 25 (Prosaro 6.5 fl oz/A at Feekes 5). Twenty two treatments significantly increased test weight compared to the non-treated check, but treatments 25 (Prosaro 6.5 fl oz/A at Feekes 8) and 27 (A15457 4.11 fl oz/A + A12705 6.02 fl oz + A7402 6.84 fl oz/A at Feekes 8) produced the highest test weight. Seven treatments, which all had only the early application, did not significantly increase yield compared to the non-treated check, while the remaining 24 treatments produced significantly higher grain yield. Treatments 5 (Quilt Xcel 7.0 at Feekes 5 followed by Trivapro 13.7 fl oz/A at Feekes 8) produced the highest yield.

The spring wheat field was planted on May 4, later than the normal planting date for the Palouse region due to the wet field condition. Stripe rust started developing in the field in early June. About 1-5% rust severity were recorded in the plots on June 8 just before the early application (Feekes 6). The second application was done on June 27 (Feekes 10) when stripe rust reached 20-25% severity in the non-treated plots. Rust severity reached 100% severity in the non-treated check plots by the flowering stage (Feekes 10.5). All 31 fungicide treatments significantly reduced stripe rust AUDPC values, but treatments 5 (Quilt Xcel 7.0 fl oz/A at Feekes 6 followed by Trivapro 13.7 fl oz/A at Feekes 10), 31 (Tilt 4.0 fl oz/A at Feekes 6 followed by Tilt 4.0 fl oz/A at Feekes 10), and 32 (Tilt 4.0 fl oz/A at Feekes 6 followed by Quilt Xcel 14.0 fl oz/A at Feekes 10) provided the best control (Table 4). Twenty two treatments significantly increased grain test weight compared to the non-treated check with treatment 25 (Prosaro 6.5 fl oz/A at Feekes 10) producing the highest test weight. All treatments, except treatment 16, significantly increased grain yield, and the increases ranged from 9.1 bushel per acre (26%) by treatment 2 (Alto 3.0 fl oz/A at Feekes 6) to 60 bushes (172%) by treatment 32 (Tilt 4.0 fl oz/A at Feekes 6 followed by Quilt Xcel 14.0 fl oz/A at Feekes 10).

Stripe rust on winter wheat.
Figure 1. Stripe rust found in a winter wheat field in Grand County on November 16, 2018.
Table 1. Differences in stripe rust severity (as rAUDPC), test weight, and yield in non-sprayed and fungicide sprayed plots of winter wheat varieties tested under natural infection of the stripe rust pathogen near Pullman, WA in 2018.

Stripe rust severity difference in test weight and yield in non-sprayed plots of winter wheat varieties.

Table 2. Differences in stripe rust severity (as rAUDPC), test weight, and yield in non-sprayed and fungicide sprayed plots of spring wheat varieties tested under natural infection of the stripe rust pathogen near Pullman, WA in 2018.

Stripe rust difference in severity, test weight, and yield in non-sprayed spring wheat varieties.

Table 3. Stripe rust severities and relative area under the disease progress curve (AUDPC), test weight, and yield in susceptible winter wheat (‘PS 279’) field plots not sprayed (No fungicide) or sprayed with various fungicide treatments under natural infection of the stripe rust pathogen near Pullman, WA in 2018.

Stripe rust severities in susceptible winter wheat plots not sprayed or sprayed with fungicide treatments.

Table 4. Stripe rust severities and relative area under the disease progress curve (AUDPC), test weight, and yield in susceptible spring wheat (‘AvS’) field plots not sprayed (No fungicide) or sprayed with various fungicide treatments under natural infection of the stripe rust pathogen near Pullman, WA in 2018.

Stripe rust severities in test weight and yield for spring wheat in plots not sprayed with fungicide.

A Word of Caution About Two New Weed Control Technologies

Effective, new herbicides are not as common as they once were. When we are lucky enough to have a new one come to the wheat industry, it is an exciting time for those of us involved in the management of troublesome weeds. It is particularly exciting when these new products can help us manage weeds like Italian ryegrass and downy brome, two weed species that have developed widespread biotypes resistant to many of our commonly used herbicides.

Zidua and Anthem Flex were introduced into the wheat market in 2015. Both products contain pyroxasulfone, which is an inhibitor of long-chain fatty acid synthesis (Group 15), that provides effective preemergence control of Italian ryegrass.  You may want to visit the WSU Weed Control Reports from 2014-2018 to see how these products worked for Italian ryegrass control near Pullman.

 

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No other weed in the Pacific Northwest has more herbicide-resistant biotypes than Italian ryegrass. It is an obligate outcrossing species with a great deal of genetic variation that makes selection for herbicide resistance more likely than in many other weed species in the region. Zidua and Anthem Flex have provided wheat growers in the high rainfall zone, where Italian ryegrass is most common, with an effective means of controlling this troublesome weed. However, research conducted in Australia and published in 2012, before pyroxasulfone was labeled for use in wheat, demonstrated that the use of sublethal doses of pyroxasulfone for three consecutive seasons selected for rigid ryegrass (closely related to Italian ryegrass) plants that were resistant to a 3x rate of pyroxasulfone. This should serve as a warning that frequent use of Zidua or Anthem Flex will likely result in rapid selection of Italian ryegrass biotypes resistant to this herbicide.

This is especially concerning now that herbicides containing pyroxasulfone are being labeled for use in pulse crops in addition to wheat. Authority Supreme, which contains pyroxasulfone plus sulfentrazone (the active ingredient in Spartan 4F), is labeled for use in dry pea and chickpea. Anthem Flex may soon be labeled for use in dry pea, chickpea, and lentil. Growers will need to decide which crop to use these products in and avoid using them in every phase of their crop rotation, or face the very real possibility of losing these products as effective controls for Italian ryegrass.

Another new weed management technology coming to wheat growers in the PNW is the CoAXium wheat production system. This production system uses a non-GMO herbicide tolerance trait in CoAXium wheat varieties and Aggressor herbicide (quizalifop is the active ingredient in Aggressor herbicide) to control troublesome grassy weeds in wheat. The CoAXium wheat production system offers growers with an effective means of controlling feral rye, downy brome, and jointed goatgrass in wheat.

 

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Quizalafop is an ACCase inhibitor (Group 1) and it is the active ingredient in Assure II herbicide, which has been used in pulse production in the PNW for many years. Consequently, many of the grassy weeds in pulse crops have been exposed to this active ingredient already and some resistant biotypes already exist, for example, in Italian ryegrass. Dr. Dan Ball, retired Oregon State University weed scientist, identified a downy brome biotype resistant to quizalofop in 2007. Herbicide resistance to ACCase inhibiting herbicides is common. All of this suggests that if the CoAXium wheat production system is not carefully managed, herbicide resistant biotypes are likely to be selected very quickly, rendering this promising system ineffective.
Zidua, Anthem Flex, and the CoAXium wheat production system are good weed control technologies, but if they are overused they will not last long and there are unlikely to be any new technologies released soon that can readily replace them for controlling some of our most troublesome grassy weeds in wheat. Use them wisely!


For questions or comments, contact Dr. Drew Lyon by email at drew.lyon@wsu.edu or by phone 509-335-2961.
Washington State University