Hessian Fly Resistance with Mike Pumphrey


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Contact Mike Pumphrey via email at m.pumphrey@wsu.edu.

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Episode Transcription:

[ Music ]

Drew Lyon: Hello, and 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. We have weekly discussions 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 podcasting app. And leave us a review while you’re there so others can find the show too.

[ Music ]

Drew Lyon: My guest today is Mike Pumphrey. Mike is the Orville Vogel Endowed Chair of Spring Wheat Breeding and Genetics at WSU and focuses on the development of high-yielding, high-quality, and pest and disease resistant spring wheat varieties for diverse Washington production environments. Mike has worked on Hessian fly resistance for 12 years through his previous position with the USDA’s Agricultural Research Service in Kansas and since coming to WSU eight years ago. Hello, Mike.

Mike Pumphrey: Hi Drew.

Drew Lyon: So, we’ve heard reports this year that Hessian fly damage fields are getting a little bit worse, and have been for the last few years. How does a grower scout for Hessian fly infestation and see whether he’s got a problem with that or not?

Mike Pumphrey:  That’s a good question. Unfortunately, there aren’t anything like a commercially available pheromone trap that you can go out and monitor. There are pheromones available, but nobody’s producing those. So basically we’re left with after-the-fact going out and looking for stunted plants with dark green tillers, fewer tillers, not very vigorous.

Drew Lyon: Okay. Will these be scattered throughout the field? Or do they tend to be in clumps? Or is there any pattern to it in the field?

Mike Pumphrey: There tends to be kind of, I would say what you might call a hot spot of infestation in certain fields. Just depending on residue left over or the source of those puparia or the insects, you know, as they go through metamorphosis. But in general, if the field has a history of fairly uniform production and has fairly consistent amounts of residue, it’ll just be a sort of patchy mosaic really across the entire field.

Drew Lyon: Okay. And why do you suppose it’s been increasing in recent years? Environment? Or too many susceptible varieties being grown? Or what’s the issue there, do you think?

Mike Pumphrey:  I think it’s a little bit of both. You know, this March is a good example. We had unseasonably warm weather in March. April kind of cooled off again. But Hessian flies really like to hatch when the conditions are I would call cool, but you know, desirable, somewhere, say, 50 to 60 degrees Fahrenheit. So in March, we had those conditions across much of the state. That coincides with seeding times. And so you have the insect hatching right at the right time when the spring wheat is established.

Drew Lyon: Okay. I remember Hessian fly-free days from my time in the great plains. And that’s dealing winter wheat. You had to plant it after a certain date to avoid the Hessian fly. So obviously, Hessian fly affects winter wheat, too. Are we seeing a problem in winter wheat?

Mike Pumphrey: You know, there have been reports of entire fields that were basically complete commercial losses over the past few years. Those were mainly in the irrigated areas. I would say everywhere where we see moderate infestations of Hessian fly in winter wheat. Winter wheat is just much more tolerant. The plants are established in tillering better. They get through the winter and kind of start growing sooner than the Hessian flies hatch. So they’re really able to outgrow the Hessian fly in our system. We do get fall infestations. And the winter wheat will be infested. And those few winter wheat fields where they are complete losses, that was exactly the problems. The fall infestation was heavy enough probably because the field was planted early enough that it was essentially a total loss.

Drew Lyon: So, is there a planting date with spring wheat that benefits or makes it more likely to have problems when we’re talking spring wheat rather than winter wheat?

Mike Pumphrey:  You know, Mother Nature comes into play a little bit too much. And in general with spring wheat, the earlier we can plant, the better in terms of, you know, establishing yield potential for the crop season. So, if we plant early and we get sort of unseasonably warm weather like we did this March, then that just means there’s going to be more Hessian fly infestation, even though we’re setting up for good crop if you’re able to plant that early.

Drew Lyon: Okay. So as a spring wheat breeder, you’re evidently looking to breed varieties that are more resistant to Hessian fly. What makes a wheat variety resistant to Hessian fly?

Mike Pumphrey:  You know, this is a really interesting insect system. These Hessian flies actually behave more like some of our fungal diseases, like say, stripe rust, for instance. There are specific genes that cause virulence or allow the insect to infect the plant. And the plant has specific resistance genes. Kind of like the all stage or seedling resistance we talked about in stripe rust. Unfortunately, we don’t know a lot about those genes. We don’t have a lot of DNA tools to track those genes. Our region has its own sort of diverse and unique Hessian fly population compared to if you were in Kansas or Indiana or North Carolina, or say, Morocco. This is a globally-distributed problem. Each Hessian fly population is really kind of establishing itself and mating locally up to three to four times a year in our environment. So, those populations can really differentiate in fairly isolated regions.

Drew Lyon: Okay. So these resistant varieties, are they just capable of surviving the damage caused by Hessian fly? Or do they prevent the Hessian fly from developing and growing?

Mike Pumphrey:  So, the Hessian fly, the female, she only lives about a day. She emerges, flies around, lays eggs. Those eggs hatch after three to five days and crawl into the leaf sheath. At that point, if it’s a resistant variety, it basically just immediately senses the sort of attack. A resistance gene shuts down those cells and does not allow feeding. And the fly basically is arrested and dies. Just starves to death there in place. With a susceptible variety, once it’s latched into the plant, it’s sedentary, and will just feed and feed and feed for a few weeks until it pupates and then can hatch again.

Drew Lyon: Okay. Very interesting. So real defense mechanisms, similar, like you say, to diseases.

Mike Pumphrey:  It’s a very active gene for gene system.

Drew Lyon: Interesting. So, if a grower hasn’t had a Hessian fly problem in the past, should he be concerned about Hessian fly now?

Mike Pumphrey: Hessian fly for spring wheat is right at the top of my list for number one traits to consider in a variety. So I say yes. There are areas where growers haven’t experienced Hessian fly infection at really troubling levels in recent years, or even decade or so. However, if you have mainly a cereal-based cropping system with abundant residue, particularly our no-till systems or direct-seed systems, we have Hessian fly. You may not see damage in winter wheat, but it’s maintaining a population. If you plant a susceptible variety in those conditions, and the weather is right, we stand to have big problems. And I think that’s what we’re mainly seeing in the past couple years is JD spring wheat. It’s a club wheat that is broadly adapted. Farmers have liked growing it. JD is susceptible to Hessian fly. But it’s being grown widely enough now that we’re basically detecting Hessian fly everywhere across the state that JD is grown. JD is not the only one. There are a few other susceptible varieties that I would avoid if you think you have Hessian fly in your system.

Drew Lyon: So, can a grower go to, say, the Wheat and Small Grains website and go to the variety testing information and see what the level of Hessian fly resistance is for a variety? Or is this information they have to go find somewhere else?

Mike Pumphrey:  No, no, we’ve done a good job with funding from the Washington Grain Commission to support an entomologist at the University of Idaho named Nilsa Bosque-Perez. Nilsa has been screening our variety trial entries annually. We update that information and put it on the Small Grains.wsu.edu variety selection tool.

Drew Lyon: Okay, good. So growers, if they’re concerned, it sounds like most growers should be concerned.

Mike Pumphrey:  They should.

Drew Lyon: And need to be checking on that particular rating on the variety testing tool. Well, good heads up for our growers out there to be on the lookout for this and to be really considering Hessian fly resistance in their varieties as they go into the future. Thanks Mike.

Mike Pumphrey: Thanks a lot, Drew.

[ Music ]

Drew Lyon: Thanks for joining us and listening to the WSU Wheat Beat Podcast. If you like what you hear, you can subscribe on iTunes or your favorite podcasting app so you never miss an episode. And leave us a review while you’re there. If you have questions for us that you’d like to hear addressed on future episodes, please email me at drew.lyon@wsu.edu. You can find us online at smallgrains.wsu.edu. You can also reach out on Facebook and Twitter @WSUSmallGrains. The WSU Wheat Beat Podcast is a production of CAHNRS communications in the College of Agricultural, Human, and Natural Resource Sciences at Washington State University. I’m Drew Lyon. We’ll see you next week.