Plant Pest Diagnostic Clinic 2022 Roundup with Cassandra Bates

Yellowing of SBWMV.
Yellowing and mosaic of wheat infected by Wheat Soilborne Mosaic Virus.

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For questions or comments, contact Cassandra via email at

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Episode Transcription:

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 from 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 podcast app and leave us a review so others can find the show too.

[ Music ]

Drew Lyon: My guest today is Cassandra Bates. Cassandra runs the WSU Plant Disease Diagnostic Clinic where she sees a wide variety of plant pests and diseases and disorders, as well as serves on the WSU Extension Dryland Cropping Systems team. She specializes in identifying what disease or pests could be ailing a plant, as well as management solutions for plant issues. She graduated from Michigan State University with a masters in entomology nematology. Her research focused on trap crop systems for the control of soybean cyst, sugar beet cyst and root lesion nematodes. From there, she went on to be the education coordinator for the North Central Plant Diagnostic Network. Then on to managing various research programs from potato cyst nematode in Idaho to tickborne pathogens in cattle. Hello, Cassandra.

Cassandra Bates: Hello, Drew.

Drew Lyon: So I wonder if you can tell our audience what the WSU Plant Disease Diagnostic Clinic is?

Cassandra Bates: The Plant Disease Diagnostic Clinic is a there’s a place, it’s an actual location here on campus, that individuals can submit samples of sick plants or plants that they suspect are sick to get a diagnosis, as well as just help on what to do with that sick plant.

Drew Lyon: Okay. So plant just looks a little out of sorts and you’re wondering what’s going on. They can submit a sample to you. What diseases or disorders of small grains have you received this past year?

Cassandra Bates: Well, we saw a lot of weather related issues with small grains. We saw a lot of physiological leaf spot and some chemical damage, potential herbicide damage, which, by the way, our clinic does not do. You have to send it to a certified analytical lab, and we have that information on our website. We also did see some burning of some fertilizer application as well. As far as diseases go, we saw some snow mold earlier in the season and we saw some rhizoctonia root rot as well as some pythium damping off. And then we also saw a little bit of stripe rust and then some Take All in some fields that were planted to wheat after multiple years of alfalfa. As far as viruses go, we saw a little bit of wheat streak mosaic virus. We also saw soilborne wheat mosaic virus, which is notable because it was north of Highway 2 and which could possibly indicate that the virus is spreading because historically it’s only been found in the Walla Walla area.

Drew Lyon: Okay. So other than the viruses, nothing really out of the ordinary. Wheat streak mosaic virus, which was very common when I was in Nebraska, it was just because we had a lot of hail events. We often had the wheat streak mosaic virus. But I haven’t heard much of it here. And like you said, the soilborne mosaic virus was pretty much thought to be just around Walla Walla but now you think it might be spreading beyond that area. So can you describe maybe the symptoms of those two diseases so if people see those, they might have an idea of what they might have there?

Cassandra Bates: Of course, with soilborne wheat mosaic virus and then as well as wheat streak mosaic, they have very similar symptoms, it’s just a matter of when those symptoms present themselves. A lot of times with soilborne, you will see that coming out of the spring, whereas wheat streak, you’ll see it later in the season when it starts warming up and the vector, which is the — a mite is usually comes on later in the season.

Drew Lyon: Okay. But then that symptom is?

Cassandra Bates: Oh, it’s yellowing of the, of the leaves. I’m sorry. [laughter] It’s yellowing sometimes you can get some stunting as well, but it, it’s not a complete yellowing of the leaves but it’s patchy, almost.

Drew Lyon: Kind of a modeling.

Cassandra Bates: Modeling. Yeah. Yeah.

Drew Lyon: It’s actually — I always had, well, unless it was severe, I had difficulty telling whether it really was wheat streak mosaic or just some other thing. So it’s not real easy. And that’s why sending a sample in for ELISA or what test do you do?

Cassandra Bates: Yeah, we do ELISA. Yes. And you are correct, Drew, in that it it can be mistaken for a lot of other things. A lot of times it presents itself as a nutrient deficiency. And that’s why, yes, you’re correct. It’s better to if you suspect virus just to submit a sample and get it tested.

And you mentioned earlier that you that you don’t identify herbicide injury, but you can kind of let people know kind of if you think it is herbicide injury or something else.

Cassandra Bates: Correct. We, the Clinic, with the aid of our weed scientist here on campus, we can narrow it down a little bit to at least say, yes, it is chemical. As far as saying the exact chemical, we recommend that you do get the plant tissue tested.

Drew Lyon: Okay. So if you had a sample that you wanted to submit to the clinic, how do you go about doing that?

Cassandra Bates: Samples can be mailed via FedEx or, you know, regular snail mail, UPS. We do hope that it is overnighted with ice if possible, or you can walk it into the clinic here on campus.

Drew Lyon: And where is that located?

Cassandra Bates: The clinic is now located in 228 Clark Hall, which is second floor. Clark Hall, you can access it off of Wilson Road, which is next to Holbert and across the street from Ensminger Pavilion.

Drew Lyon: Okay. What are some of the common mistakes people make when they when they send samples? I know you’ve brought me a few. That’s like by the time they get to me, I’m not sure what’s going on.

Cassandra Bates: A lot of the mistake is really is not submitting enough information, as well as not an adequate sample, because by the time maybe you start seeing the symptoms and then you wait and wait and wait, it’s too late to make a diagnosis. But probably the biggest problem I see is just not getting enough enough information with the samples provided.

Drew Lyon: Okay. So is there a sample form people can access? And if so, where do they get that?

Cassandra Bates: Yes, there is on our website which is Or you can just access the WSU Plant Pathology website and there is a tab on the left hand side for the Diagnostic Clinic and on that site there are — it’s the plant problem form that you would want to fill out as best as you possibly can.

Drew Lyon: Okay. What kind of information that they ask for on that form?

Cassandra Bates: Your name. [Drew laughs] That usually a big thing. And then just how the plants were grown. What is the variety? What were any chemicals applied? Can you explain the weather during that growing season? Do you know the soil pH? You know the soil type. When did the symptoms present themselves? When did you first notice them? How much of the plant is exhibiting those symptoms? How much in the whole field is having this the problem?

Drew Lyon: Okay, so I know when I have been out to try to diagnose problems, the pattern in the field is really important to getting a feel for it. So can people submit a picture of of the field or the location where the problem is occurring? Would that help?

Cassandra Bates: Yes. Yes. Pictures are worth a thousand words when it comes to diagnosis because like you did say, Drew, distribution in the field really helps because that can also help narrow down if it truly is a disease or if it’s possibly something that is chemical in nature or even weather in nature.

Drew Lyon: Okay. So when sending in a plant sample, how much of the plant should one send in and should they send it along with soil or just what? I can imagine several different ways somebody could just pick off a leaf. Somebody could take the whole plant. Somebody could dig up the roots with the plant. How how much of a sample are you looking for generally? And do you want it both from the plant showing symptoms as well as maybe what’s considered a healthy plant?

Cassandra Bates: Yes, we always prefer having both healthy and sick tissue as well as if you’re able to that in-between stage between the you know, maybe you have a plant that is kind of starting to show some symptoms, but is for the most part still healthy. And if you’re able to give roots with that sample, that also helps. Soil helps as well. Just a single leaf doesn’t really do much. So the more plant tissue you can provide, the better. I once received an entire large tree, so it ranges. [Drew laughs]

Drew Lyon: What about fee? Is there a fee for the service or how do people do that?

Cassandra Bates: There is a fee. There is a fee. It’s $40. Is the base fee for diagnosis. And then depending on which tests may need to occur, then fees might be added on to that.

Drew Lyon: Okay. And then in addition to diagnosing the problem, do you also provide information on how to deal with it? Or do you just provide you know, this is what you have —

Cassandra Bates: Yes.

Drew Lyon: — and here are go talk to your county extension person or what’s the —

Cassandra Bates: I mean, I do always try to direct people to their County Extension Agent because they’re the ones in that county. They are more familiar with that area. But I do provide information, background information on the diagnosis. So, for example, if something came in with snow mold, I do provide information on snow mold as well as how to potentially prevent it for next year. And then, yeah, just trying to provide as much information as possible and recommendations for control.

Drew Lyon: Okay. Well, I appreciate you taking the time to come here and tell us about the WSU Plant Disease Diagnostic Clinic. I know your reports to the extension dryland cropping systems team and what you’re seeing is very helpful to us as we try to think about what kind of information to send out to growers so appreciate that and hope our listeners will keep you in mind when they next have a problem in their field or in their yard.

Cassandra Bates: Thank you, Drew.

[ 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 podcast app. If you have questions or topics, you’d like to hear on future episodes please email me at drew.lyon — that’s — ( You can find us online at 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.

The views, thoughts, and opinions expressed by guests of this podcast are their own and does not imply Washington State University’s endorsement.