Pennsylvania Turfgrass – Julie Holt, Content Director, TheTurfZone.com
TheTurfZone: Welcome to TheTurfZone. In this episode, we continue our series on the USDA-funded ResistPoa Project. In this episode we’re talking Shawn Askew, Professor at Virginia Tech, and Clebson Goncalves, post-doctoral associate at Virginia Tech. Welcome, Shawn and Clebson.
Shawn Askew: Thanks for having us.
TTZ: Thanks for joining us. So let’s get right into the ResistPoa Project and your part of it. Most turfgrass scientists have had, for lack of a better word, a professional relationship with annual bluegrass for their entire career, what’s your background and history with poa?
SA: Like you said, as with most turf specialists that do work on weeds, within the first week on the job, I was handling questions related to poa annua, and it’s just so pervasive in the industry. It’s just one of those things and not just if you look at it across the country or regions, whatever. It’s everywhere – it’s global, but temporally, looking back in time. Poa has been a problem in the United States for as long as we have managed turf. I’ve found publications back in the 1920s where poa was a routine, it was as common then as it is today as a weed of turfgrass. If you thing about the characteristics that we would apply to it today, the exact same characteristics were applied back then. They called it “poa” in short. So it was already so old of a problem that they had a shortened name based on the genus in 1921. They observed the seasonal fluctuation in population levels, the seed production, the aesthetics, how it decreses aesthetics, was all commonplace. So this beast has been with us for quite some time and it’s probably not going to soon go away.
TTZ: With that long history and knowing that it has been a challenge and has been present for so long, what is the hope with the ResistPoa Project, what new knowledge or what new management techniques are we hoping to gain from this project?
SA: When you look back at what has been done, prior to the ResistPoa Project, it’s mostly chemical herbicides, predominantly synthetic chemical herbicides and those are the strategies that have been evaluated for so many years and that largely have failed for so many years. We have some solutions on the market, but for poa annua, they are often difficult to implement, complicated requirements, need a temperature zone that you have to be in or you get too much turf injury, so for the longest time it’s been difficult to find a true selective herbicide for this weed. Now that may be changing, this is off topic, that may be changing with this new herbicide, methiozolin, PoaCure, which actually is not part of the ResistPoa Project, but ResistPoa was born out of the challenges that we have experienced with conventional herbicides. So what it’s going to do is expand our knowledge a little bit better on those aspects of poa annua control that are now solely dependent on which synthetic herbicide to spray today or tomorrow or next week. We’re looking more at the biology of the weed and trying to exploit its weaknesses. We’re looking at how different types of turf would be more or less competitive with annual bluegrass and we’re also, to speak to the synthetic herbicide issues that we often see, we’re looking at the widespread resistance of poa annua to the various herbicides that we do have. So we have limited options in turf for annual bluegrass control because of the similar physiology between the weed and the turf, but even the few options we have, poa annua develops resistance to them very rapidly. In fact, this weed, annual bluegrass, is one of the most adaptive plants on the planet. It’s one of the only higher plants that can survive in Antarctica. It also is one of the most highly-ranked plants on the herbicide database, the weed science database that we have for herbicide resistance. So poa annua has developed resistance to pretty much every ...