Vineyard Disease Management: Expert Forum Discussion

- Alright, well we will get started.

Apologies for starting a few minutes late here.

Thank you for your patience and thanks again for joining us today.

I'd like to welcome everyone to the Third Viticulture webinar, and I think fifth overall webinar of the fifth edition of the Eastern Viticulture and Enology Forum.

We started this back in 2020.

So even though Penn State's hosting this forum, this webinar series, it is by far a solo mission from Penn State.

I have so many colleagues from these land grant universities listed here that have helped me coordinate this and decide on topics and speakers.

And without their help in collaboration, this wouldn't be possible.

So truly is collaborative in spirit and it is truly Eastern Viticulture and Enology Forum because of the collaboration.

And so it's great that we can share resources across state lines and use technology in doing so.

And there's also an enology portion of this series that I will show right now.

So this has been the 2025 series schedule so far.

And of course today's March 11th and we're having our disease management forum discussion.

And then on March 18th, a week from today, there will be an enology webinar.

And then about a month later we'll have our final viticulture themed webinar for the year.

And then two weeks after that, at the end of April, we'll have the final Enology themed webinar for the year.

So hopefully you've been enjoying these this year and hopefully you have for the last several years that we've been holding these, again on behalf of all the colleagues that have helped me coordinate this and collaborate on this, we're grateful for the participation.

We've had upwards of 350 to 400 people register for these webinars this year, which is great.

So thank you.

Okay, so today is our Vineyard Disease Management Expert forum discussion.

This year we've taken the approach of formatting these webinars in a true forum roundtable format.

We've accepted pre-submitted questions.

Maybe some of you have pre-submitted questions through the link when you registered.

If you did, great, thank you.

If not, you can use the chat to type in questions.

We will get to those questions later if there's time, but this is truly a open discussion question and answer type format rather than a formal webinar presentation.

So we're mixing things up a bit and seeing how this format works.

So with that, I'd ask everyone listed here and starting with Femi to go ahead and introduce them themselves because these are our lead panelists for this disease management theme webinar.

So Femi, if you want to kick things off, that'd be great.

- Sure. Thank you everyone.

Ofufemi Albi is my name, I'm a professor and extension specialist with Texas A&M AgriLife Extension.

I'm in actually the southern part of Texas, but I collaborate with my colleagues across the state, you know, to lending my expertise.

I'm a plant virologist by training.

I did some of my PhD and postdoc work on Grapevine leaf rot, and I've been working with Grapevine, you know, virus diseases in general since I moved to Texas A&M.

Thank you.

- Thanks Femi.

- Michael?

- Oh sorry guys. Hey howdy. Michael Cook here.

I work with Femi and another colleague Justin Scheiner, who's on the call.

I am a viticulturist with the Texas A&M AgriLife Extension Service and I'm based out of the Dallas-Fort Worth area.

- Thanks Michael. Katie?

- Oh, it's my turn.

Hi, I am Katie Gold.

I'm assistant professor of grape pathology at Cornell University based at Cornell Agritech in the beautiful Finger lakes of New York.

- Thanks for being here Katie. Bryan?

- I'm Bryan Head.

I'm plant pathologist for Penn State University, working pretty much exclusively on grapes.

I'm located up in the northwestern corner of the state along Lake Erie where there's about 10,000 acres of grapes in Pennsylvania.

But I also field questions for the rest of the state as well.

- Thanks Bryan. Mengjun?

- Hey everyone. Mengjun Hu from University of Maryland.

I been mostly working with a bunch (indistinct)

and you know downy mildew as well concerning fungicidal resistance with Bryan Head.

Yes, obviously small fruit pathologist or you know, also wine grapes.

Thank you.

- Thanks Mengjun, Sarah?

- Hey, I'm Sarah Lowder.

I am the Extension Viticulturist and Assistant Professor in the horticulture department at the University of Georgia, based out of Athens.

Have done a lot of work on powdery mildew, especially in funder side resistance in powdery mildew in the past.

And now that I'm in Georgia, I get to work on all of the diseases so it's pretty fun.

- Great, thanks for being here Sarah. Tim?

- Hi everybody. Tim Miles, Michigan State University.

I'm a small fruit pathologist and in grapes, mostly focused on the anti-mildew, powder mildew and vitis and also sour rot too.

And been involved in the Frame Project which looks a lot of fungicide resistance and yeah that's me.

And in Michigan we mostly have a mixture of juice grapes, hybrids, and wine grapes as well.

- Thank you for being here Tim, Charlotte?

- Hi, I'm Charlotte Oliver.

I'm the viticulture extension specialist for Colorado State University.

I am stationed over in Grand Junction, so very far away from main campus.

And I'm mostly am the pathology person here.

I've done a lot of work with powdery mildew with both Tim and Sarah and I actually started things off back east working on rots so I don't get to have any fun with those anymore, so.

- Thanks Charlotte, and Justin.

- Hey Justin Scheiner with Texas A&M University.

I'm an Assistant Professor and Viticulturist, and I'm located in College station on main campus.

- Excellent, thank you. Thank you Justin.

Thanks to each of you for taking some time outta your day to join us at this webinar.

So we are recording this webinar.

It gets sent out if you registered.

So all of you will get the recording.

It will be posted online within the next couple weeks.

You can use the chat and question and answer functions throughout to engage, ask questions, make comments.

This is your chance to tell us about your observations.

They don't just have to be questions coming in.

We will monitor questions, I'd ask all the lead panelists here to monitor questions and type answers as they can.

If there's questions left at the end, we will try to address those.

But again, we have some pre-submitted and planted questions that we thought would be worth addressing as well.

So I will share a survey towards the end of this webinar in the chat box.

So we will get started.

And the way this is set up, I'll ask a question, I'll copy and paste that question in the chat and then one of the lead panelists will start by by answering that question.

But then each lead panelist will have an opportunity to add context or an add their experiences with that, okay?

So let me get the first question going here.

Okay.

so Bryan, we'll start with you.

So the question is, I have been trying spray after every rain for fungus using various fungicides.

My question is, should I just wait until I see that an application is needed where a fungus starts to show up or stay on my program of weekly or after every rain spraying program?

- Okay, well this is a big question.

We get these questions a lot, particularly with some of our juice growers.

I guess I would start off by saying that waiting until after every rain is exactly what we would not want you to do as far as applying fungicides.

Generally, you know, when we look at what it takes to control fungal diseases as opposed to say insect pests on grapes, there are two different philosophies.

With insect pests you can monitor for their presence and you can, you know, when they get to a certain threshold you might apply an insecticide.

It's just the opposite with fungal diseases.

You don't wanna wait until you actually see it before you do anything about it.

And a lot of times, you know, we know growers do that in some cases and it just makes it so much harder to get it back under control.

And in that case, you know, you may have lost some of the cash of your crop already.

So here in the east where, you know, it's not like California where it doesn't rain for three months out of the year, out of the season.

And you might be able to use models to, you know, make your applications before an infection period before a rain period.

Here in the east, since you know, I don't know where this grower is located or what they're actually growing, that would make a difference too.

But in general here in the east we get rain so frequently and regularly that we generally recommend that growers stay with a spray program that follows the development of the vines.

You know, basically we tell growers to start off with a spray for Phomopsis early in the season at about two to five inches of shoot growth.

If you're growing vinifera, it might even be earlier than that, it might be at one or two inches of shoot growth, particularly if you've had a really bad year with powdery mildew the previous year.

So that has a lot to do with the timing of your sprays, especially early in the season, how bad the disease was in the prior year.

The worse it is the earlier you need to begin spraying for it to get it back under control in the subsequent year.

So, but generally, like I said, and others can, I'm sure all of you here have something to say about this.

But I would say that you know, we stick to a schedule at least through the pre bloom period, through bloom and into the early berry development period where we apply fungicides on a regular basis, about 10 to 14 days apart.

Starting with that three to five, two to five, two to six inch shoot growth stage.

And there you're targeting primarily Phomopsis, as you get into another 10 to 10 days, two weeks later, depending on weather you might be at eight to 12 inches of shoot growth, we apply another spray at that time.

Here we're targeting things.

We might be starting to include powdery mildew.

If you've got wine grapes, particularly vinifera.

For juice grapes, again, you might actually be able to lay off until your immediate pre bloom spray, which would be another 10 to 14 days.

But that's how we would do it generally.

Three, maybe four pre bloom sprays depending on where you are and depending on how sensitive to disease the varieties are that you're growing.

And then I would say the two most important sprays of the year would be your spray just before the beginning of bloom anticipated bloom.

And then about 10 to 14 days later, those two sprays are gonna be the most important for controlling fungal diseases on your fruit.

That's when they're fruit, are gonna be most susceptible to all the major diseases.

black rot, Phomopsis, powdery mildew, downy mildew.

No matter what variety you're growing, once you get past that first post bloom spray, things change a little bit depending on what varieties you're growing.

But again, you may still wanna stick to, another 10 to 14 day period before you apply that second post bloom spray.

And here we're, you know, we may still be targeting all the major diseases, particularly if you're growing vinifera, the native varieties might by the second post bloom spray have developed a fair amount of resistance in fruit to things like powdering downy mildew.

They're still gonna be susceptible to black rot, to Phomopsis, but by about the time of the, you know, but again backing up a little bit before I leave that second post bloom spray, if you're growing vinifera, you're probably still gonna want to protect it against powdery mildew.

You want to at that time, although the fruit is developing resistance.

and here we're talking, you know, maybe three, four weeks out from bloom, you might still be able to on vinifera especially and sensitive hybrids, you might still get these small microscopic infections of powdery mildew.

Because berries aren't quite fully resistant.

And that can set you up for small injuries on the skin of the fruit that can lead to easier ingress of bunch rot pathogens later during the ripening period at the end of the season.

Once you get past that second post bloom spray.

And again we're talking, you know, 10 to 14 days between sprays generally speaking.

And a real wet year, especially with vinifera you might wanna close those intervals down to seven to 10 days, especially between that immediate pre bloom and the first post bloom.

And I know I'm kind of going on and on and on here (laughs).

I can talk for a half hour about this question.

- I can listen to you forever, Bryan.

- But well I'll let somebody else chime in here.

I mean once you get past the second post bloom spray, things start to change a little bit from protection of fruit to protection of primarily leaves, okay.

And by leaves we're talking primarily powdery and downy mildew for the rest of the season.

For natives, maybe not more than another few weeks.

If you want to keep the canopies firing on all cylinders, you got an enormous crop, you gotta get ripe.

for vinifera, you're definitely want to get, you know, wanna keep protecting them against powdery and downy mildew and pay close attention to the weather.

I'll leave it at that and let other people chime in.

- I'll chime in, I just wanna, you know, like boost and endorse what Bryan says.

If you wait until you start, you see the disease to start spraying you've already lost.

Prevention is absolutely key.

And that is even more so the case with cluster disease control.

So starting about 10 inch shoot growth, I'd say that immediate pre bloom through a couple weeks post bloom, that's your entire cluster disease control for the year.

And if you nail that period, you're clean on the clusters, you don't have to worry about them.

The berries have antigenic resistance, they will no longer be susceptible to powdery mildew, downy mildew or black rot.

So it's really important to do preventative sprays during that period.

Once again, you know if you wait to see the disease before you start spraying the game's already over.

- I was gonna add something about systemics versus contacts.

So in some cases that's probably the part to think about a little bit more.

I think when you think about rain events, it takes a day or so for a systemic fungicide to really be incorporated into the plant a little bit.

It needs to kind of dry but then get absorbed a little bit.

So if you knew it was gonna rain on like a Wednesday or something, might be important to spray a systemic fungicide maybe Monday morning or Tuesday morning because that's gonna provide you some control 'cause it's gonna be absorbed by the plant prior to the rain.

If you didn't have rain events, it might be appropriate to like use a contact in some cases throughout the season.

It probably would be appropriate after, if you really were concerned that you had like a big sporal dispersal event, it probably wouldn't be a bad idea to come in with a contact after the rain was over.

But spraying a contact before a rain event probably not that useful because you might kill what you touch but the residue will be lost relatively quickly.

So if you were gonna be guided by the rain in any way, it might be useful to think about whether your products are systemic or contact.

And you kind of know that based on like what FRAC code they are.

Most of the time a lot of your newer biologicals are...

They tend to be contacts a little bit more often and a lot of the older chemicals tend to be contacts as well.

But if they've got a number like one through, we're up to 50 I think, one through 50, they're generally formulated to be at least somewhat translaminar.

So they'll get absorbed in some way by the leaf and be there.

So I think it's nice to think about whether the fungicides a contact or a systemic if you're thinking rain, but I agree with everybody, you definitely wanna spray before a rain event and most likely spray on a calendar schedule 'cause all these fungicides don't work that well after an infection event already happens.

- Yeah, is what my colleagues have said, just wanted to add something from the perspective of fungicide resistance development.

Now, you know with a cyto -specific fungicide like Tim mentioned, you know it's going to select for resistance.

There is a resistance risk.

You know, if we were to apply those cyto-specific fungicides prior to infection, what's gonna happen is that only resistant population or strengths will be able to grow right?

After you apply single-site fungicides.

But if we wait a little bit until, you know, you see a little bit infection to apply those single-site fungicides, my point is that you might allow some time for the sensitive population to grow together with resistant population.

Just from that resistance management perspective.

Post infection spray could benefit resistance management in some cases.

You know, that's just a common...

But I agree with what everybody just said in general.

- We wanna move to the next one.

- Great discussion, that's a great opening question and answer.

That's exactly how I hope this would go.

So thank you all for engaging.

I will go ahead and ask the next question and copy it and paste it in the chat.

And that question is, we'll ask Tim to lead this one, what can you combine with copper for downy mildew control?

- So most chemicals are compatible with the with copper.

I guess if we're...

It might be useful to think about why you're incorporated copper with what you're spraying.

So if you're trying to hedge your bets for resistance management, if that's the plan.

So out west it's quite common to incorporate a low amount of sulfur with a like a powdery mildew fungicide because you're concerned about resistance to development.

So if the purpose of the copper is just to be a multi-site there to help with resistance for the downy mildew, most of the numbered FRAC codes like, well I'll just use the trade names, like things like Zampro or Revus or those sorts of products are compatible with copper.

The thing that maybe you want to be a little bit careful of, is some of the hybrids and some of the juice grapes can be a little more sensitive to copper.

So that's just an important thing to think about.

It's probably worth it to spray any kind of mixtures you're doing with chemicals that aren't specifically spelled out in the label as a thing to do.

It's probably worth it to spray it on a few vines.

You can do the mixing test just to see if they're gonna actually cause problems through the sprayer, but then maybe spray it on a small block of vines.

If you're curious, like if you potentially are putting in an adjuvant in there that you've not used before or you're using a different water source or there's an insecticide in there too, it might be worthwhile like, you know, just spraying a few vines.

That's usually my kind of recommendation for that.

The other thing to think about with copper, I think that it's a product that we do use it a fair bit in grapes, but I think we've gotta get a little more comfortable with copper for folks that aren't using it a lot.

Just because there's headwinds with some of the multi-site fungicides.

So Xyrem may not be around by the end of this year most likely.

I've heard that it's gonna be hard to get either way.

And then there's issues with Mancozeb, and essentially the only real multi-site we kind of have that fits that role is capped in and copper.

So I think that it's an important thing to think about.

It's got black rot activity, it's got Phomopsis activity and it also has downy mildew activity.

So I think that we'll probably have to start getting more...

If we're not using it now, you might need to like start thinking about how to use it and there's many kinds of copper formulations that are available.

Some that you can use with a shorter PHI, and some you can't.

One thing about copper is that with wine grapes, hybrids or vinifera, there's issues with stuck fermentation with that with copper.

So you can't use it super late in the season.

So it wouldn't be a good downy product later just because there's the known issues with making wine.

And then the other thing to be careful of with copper besides the phytobe besides the wine issues, is potentially the soil and water issues.

So copper's not really like sulfur, it doesn't, you know, go away in the environment or break down in the environment.

It really does hang around in the soil and it's relatively easy to test for.

So if you've been using copper for a while, it might not be a bad idea to get a soil test once in a while just to see, you know, what does a season's worth of usage look like for copper and is it, you know, what is it doing to my soil essentially?

So yeah, that's some of my thoughts there.

But maybe I'll open it up to my other fellow panelists to talk about that.

- I wanna comment on the idea of biologicals, right?

A kind of against all odds, it appears as though some of the more modern biologicals that we've been receiving actually do have surprisingly broad spectrum activity.

But it is very important to understand that that broad spectrum activity is just fundamentally different from what we think of when we think of copper, Mancozeb, Captan.

Biologicals just operate in different ways.

But we do see that many of them for example, like Howler EVO, LifeGard, we see that they have activity on powdery mildew, downy mildew and black rot.

So they can be a good choice to mix with copper, especially if you're trying to go kind of more organic.

Something important to consider as well when you're looking to mix something is that my dear colleagues Bryan and Tim, have given me the wonderful news that we have a triple resistant downy mildew and my pathology vineyards and unfortunately it seems to be quite common around the Finger Lakes of New York, at least.

We're resistant to the strobes, we're resistant to revis.

So FRAC 40 and now Bryan told us we got (indistinct) resistance.

So something to consider is that if you are...

I think tank mixing with copper is a great solution.

It's not a perfect solution, but it is important to try to back up those remaining chemistries that we do still have for downy mildew, which include RANMAN, half of Zampro is still good.

And then of course you know Ridomil, probably the best omacide side ever created, however just dangerously prone to resistance and wildly expensive.

So once again, no perfect solutions there, but tank mixing will help protect the longevity of those remaining omacides that we have for downy mildew control to try to extend their livelihood as long as possible.

- Another thing I'd like to add to this question is, it asks what you can combine with it.

I would also like to say there are probably some things you shouldn't combine with copper.

Maybe some of those things have been mentioned, but anything that would acidify the mix with copper could make the copper more soluble and kind of hike up the possibilities or the potential for phytotoxicity injury to your plants.

Things like, you know, Phosacid is a downy mildew fungicide, I've never sprayed copper with Phosacid, but I would recommend not doing that, not mixing those, not tank mixing those.

And anything else that might lower the pH with a copper product because as I said, you would be increasing the potential for phytotoxicity to occur.

Other things could be, there might be some liquid fertilizers or foliar fertilizers that lower the pH.

And there might be things like a lot of insecticides need to be applied in an acidic mix.

And that's not gonna be compatible with a copper spray, which you want an alkaline mix, a slightly alkaline mix.

So in some cases we even add lime to copper to make that mix more alkaline above pH seven, maybe pH eight or nine.

And that may be incompatible with insecticides and even some other fungicides as well.

So another thing to think about.

- I'd like to comment just briefly from a practical standpoint, and this relates to the first question a little bit as well.

When used, particularly with downy mildew, you know we frequently get into periods where we have rain five days in a row, six, seven days in a year.

The challenge for us especially trying to apply after rainfall is you don't know when that spray window is going to be and it's very challenging.

And that discussion of contacts also reminded me of that something like copper, I mean I'm fairly hesitant to use it alone if we're in a period of time where downy mildew pressure's extremely high.

- Anyone else about copper related sprays or issues or?

We've got some questions that have come up.

- I'll try to type a little bit in the chat for people with my questions.

- Well, so if the questions can go to the Q&A, then we can all kind of respond to them in writing.

- Okay, sounds good.

Alright, we will go on to the next question which we will ask Katie to start us off.

And the question is, are there any organic options available for small scale vineyard owners?

- There are options available for small and large scale vineyard owners.

I think everyone growing grapes should be considering using biologicals.

It's not just an organic only thing.

So the question is though about organic options, right?

My program for the past five years, we've been doing a ton of testing with new biological products.

So kind of beyond the essential oil cocktails, new products that are a range of living agents to extracts that have come out of the genomics informed selection era.

So they're quite good. I've been very impressed with them.

For the most part, most biologicals would qualify for organic.

Not all of them have gone through the specific process of becoming organic approved or the formulation itself is not necessarily organic approved.

Such as, you know, the inerts and the mixers that are within there.

However, if you're looking for like certified organic, it is really important to consider that exact formulation.

For example, you know we've worked with a product called WarHammer, and we're testing the two formulations.

One is WarHammer regular and one's War Hammer Organic.

It's the same active, the Chitosan, but it's just the formulation that differs it.

So important to consider if you're looking to grow official organic.

However, if the question's kind of a more broad, like I'm looking to kind of go a little more soft, especially to looking at forthcoming EPA regulations and also looking at what's coming down the pipeline.

You know, the era of just having new conventional chemistries to go to when one get burned out, it's just not there anymore.

So the biologicals are what's there.

Most of them are all would qualify for organic but are not necessarily officially registered.

Does anyone else have any comments on that?

I know I'm not the only one testing them in my vineyards.

Tim, you just told me on the phone.

- It's true. Do I have stuff to add is always the question.

(Katie laughs)

Small scale, I mean I think the main issue with small scale is there's different disease pressures going on at a small scale vineyard.

There's a lot of edge effects happening, I know there's certain growers that are growing a half an acre or an acre of grapes, then there's other ones that are growing like 400 acres.

And so there's different...

I mean the disease pressure will be quite different.

So I'll give just one example.

Like I have a grower that has a block of Vignoles that's right up against the woods.

There's literally no airflow there.

And biologicals don't work very well there because they really get a lot of sour rot.

But if the disease pressure is lower and there are resistant varieties, I think there's a lot of organic options, especially for downy mildew and powdery mildew that are available.

And it kind of depends a lot on disease pressure.

- And I have a question too, Katie and Tim, you might be able to interject.

So I think maybe part of that question too is from a, you know, purchasing standpoint, you know, a lot of these products may be in two gallon jugs.

Do y'all see different formats with maybe a cheaper price?

Maybe this is a petting vineyard in front of a winery and so it's not even half an acre or something.

Or are you saying it's fairly large formats for most of these biological products?

- That's a great question and actually one that I've been asked quite a bit lately.

It's harder for us to get a hold of some of that information, right?

In terms of like what is actually the most cost effective means?

I can tell you that like I've been delivered biologicals in all forms from like powders and pellets to slurries I keep in the fridge, it's really a range.

I do wanna add just along Tim's comment too, you know, disease pressure is so important.

We see that, you know, biologicals even of the best of them when the disease pressure is too high, they fail.

As well as, but you know, we also see our conventionals fail when the Cornell pathology vineyards are really doing their thing.

I tend to recommend rotations or if you're interested in biologicals, don't go full Monty.

Think about rotating them with the chemistries that you're used to using.

All of that will still get you that benefit of reducing your overall exposure of your pathogen populations, to the chemistries that are resistance prone.

And there was also a question there about some names of biologicals.

So we've been working with WarHammer that's active in chitosan, it's from the crab shells I think.

Very pleasantly surprised with its downy mildew control.

LifeGard is a classic defense inducer great for powdery and downy how are the new reformulation Evo?

Very impressed with that.

I also like the combination of Regalia with Stargus.

Those are from the former Marrone Biosciences now Pro Farm Group What's unique about that is that Regalia is a plant extract and then Stargus is a living agent, but Stargus was selected in the presence of Regalia.

So there are a nice synergy there. It's a good combination.

EcoSwing is a really nice one for powdery mildew.

We've pleased with that lately.

And then just to throw out one there for Botrytis, BotryStop, it's great.

- I may have missed it, sorry.

But we get a question about shelf life for these products quite a bit and I was wondering if you could possibly comment or if you knew anything about that.

At one point I had a student contact all the manufacturers of all the vineyard fungicides and insecticides and request that information and it was interesting.

And so that always swirls around when you buy online, especially for small vineyards, you don't know how old the product actually is when you receive or how it was stored because there are those storage conditions that are listed on the label.

- Yeah, so I would say that, you know, fresher product's always gonna be a better way to go.

So the closer you can get to the source or if you have an in and know when that product is produced, that's great.

It kind of goes back to the idea of can you mix biological...

there's a question in the Q&A about mixing copper with a biological or is it possible?

And I think that it's nice to know what exactly is the active ingredient in some cases.

So like Regalia is an extract, but Stargus is a living organism.

So I'd be a little more concerned about the half-life of Stargus versus the half-life of Regalia.

Because one's a plant extract and one is not.

So I don't have a great answer for you Justin, but I essentially the, you know, the fresher of the product the better.

Just when we do fungicide testing, I try to never use anything that's more than two years old.

But that's just in our own program.

We typically store pesticides at like about 50, 55, in a chemical locker at the university.

So I couldn't answer more than that.

There are some information on the label as well, so.

- To add a little extra fun when it comes to Stargus, I just talked to the Proform guys and they're recommending spraying Stargus with like Jet-Ag, which is their form of a peroxide agent.

So it might be more resilient than a lot of these other living agent biologicals.

So we might eventually have an additional problem of our living agents aren't always as resilient as others.

So that just adds another fun layer on top.

And also another question kind of in the Q&A, about mixing copper with Regalia.

And I'm not sure how it is on some other things.

I did have a little bit of experience mixing Regalia and copper in an organic setting in Virginia.

And it did great except on our Chambourcin, we ended up with a bunch of phyto talks.

So we could have had some issues with the pH of our water.

It could have just been a bad day, that it was too hot, too weird on the relative humidity, don't know.

But that is something that we did see.

So I would highly recommend if you are doing that kind of combo, maybe it was also 'cause we had Serenade in it.

I don't know, give it a test on a small block first, see what happens, because I'm all weirded out by it now.

- No, I think that's a great suggestion.

It's always good to test.

One thing that we've noticed kind of casually over the past few years, Gatten, great product for powdery mildew control, doesn't seem to play nice with the bios.

And recently maybe it was Tim, one of you great pathologists told me you'd observed the same.

And I was like, oh thank God I thought I was going crazy.

And so there is reason to believe that sometimes, you know, these are living agents, right?

And we're spraying fungicides and you know, pesticides.

Like there's reason to believe that there's incompatibility.

We're starting a small scale trial this year to try to break out and see actually in kind of more rigorous replicated way to see if they're...

So we can, you know, identify and like come up with like, okay, yeah these don't act, these really don't play nice together.

But you know, there's reason to believe that there are some better combinations than others.

But we unfortunately, there was gonna ask for a list of compatibility.

We just don't have that yet.

- You know, I just wanna throw in a comment regarding the efficacy of the biological materials.

I think Katie, you had a lot of success in your area.

I mean Tim might also have some success in Michigan.

So I've not done a lot with biological materials.

I tried several including Regalia, Stargus, as well as the LifeGard.

Really, I mean none of them worked for me in our climate.

I mean we tend to have a high disease pressure, like you said, Katie said, you know, the success may dependent on, you know, the disease pressure, right?

If you have high disease pressure, some of those bio biological materials may not be reliable.

You know, the only material that I had somewhat a success was Howler.

But it turns out that the active ingredient of Howler actually is a...

The same chemical class as (indistinct)

that's the active in grading in switch.

So just throw something out there for comments.

I think Bryan, you also had tried LifeGard and you did not say efficacy for downy mildew.

Maybe you can comment on that as well.

- Well one of the problems we had is we tested it during two seasons where we had very little downy mildew.

So it wasn't a good challenge, it wasn't a good test.

I did run some separate little tests with inoculations on potted chardonnay vines.

And I did see some activity on downy mildew.

Not quite the activity that Wayne Wilcox had seen when he initially started testing it shortly before he retired.

And, you know, I didn't get the results that Katie has gotten, but you know, I've seen...

It may just be a, you know, a matter of some inconsistencies either with the product or maybe little small differences in the way it's applied.

And you know, when I looked at it in inoculations, it seemed to actually do...

I got more direct information from that and it definitely showed some efficacy but not the level that I was hoping for.

- I think we've had pretty good success with LifeGard, but it's been better.

And again, that's the issue when you do these kinds of trials.

It's been better in a program though when it's been used with other chemicals.

So a lot of the reasons to use it, not isn't necessarily to go organic.

It's been more to reduce the overall pesticide amount, you know, like that you're putting out there.

So I admit that's why our growers are interested in it for that.

Yeah, plus they're looking for other modes of action 'cause they have so much resistance I think that's...

That they're trying to find another mode of action essentially.

So that's been the interest in that particular chemical here.

But I would say downy mildew worked relatively well for us for some of the biologicals of all of them.

But we get really bad control with a lot of these things on black rod.

Like black rot just, that's like...

But black rot just doesn't care about.

I mean for the most part it's just not a disease that we can get good control with any of these soft chemicals, so.

- Yeah, so I will say I see the same, right?

Some tips I guess for LifeGard.

So I know it's drove Bryan nuts for years that she can't get our results so ha-ha Bryan just teasing you.

But we got way better control when we switched to 10 day intervals for our biologicals in particular for LifeGard.

Certis always says to start with LifeGard and then rotate.

We've seen that works pretty well for us.

We started a trial last summer, kind of like more rigorously testing that and we saw no statistical or numerical difference between starting with the bios and then you know, going bio, conventional, bio, conventional versus conventional then bio, conventional then bio, so there's that But also I think in some of it's you just gotta adjust your expectations, right?

You know, like if like a great control from a biological straight through is just never going to be the same that you could potentially get.

And this is not talking to my peers, this is talking to, you know, the audience here, right?

It's just simply not going to be the same, as what you might expect from a conventional right?

They just fundamentally work differently.

But you know, as Tim says, I think where they really can shine is in rotation it gets you the best of both worlds.

It gets you a product that has no resistance risk.

For example, you know, a biological like LifeGard that's inducing defenses within the plant.

Fundamentally the pathogen population cannot become resistant to that.

It's not acting upon the pathogen.

And that's a really powerful tool in the context of a season long program.

Especially you know, when we are fighting resistance as well as potentially losing our broads to regulation.

So, you know, I encourage the use of rotations for biologicals.

I really don't encourage trying to rely on them straight through.

That's kind of the take there.

And then I will say one year we got fantastic black rot control with Regalia Stargus, and then couldn't see it another year.

And then Dave, I was just messaging my field research manager, some decent black rot control we saw with the new reformulation of Howler, Howler Evo.

Once again that was just one year only though.

- Yeah, I mean black rot is a, like you mentioned, it's a tough one.

It's a really tough one.

And that's the one that for years I tested, and this was quite a few years ago, we got some funding to look at organic back in 2005 to 2008.

And I tried just scores of different materials mainly for black rot 'cause that was, you know, Wayne Wilcox was, to him it was the Achilles heel of the organic grower.

And I could never get anything to work except copper.

Copper only provided modest control but it did provide some control.

But none of the products that I tried really made any difference at all unfortunately.

That's a tough one.

I think, you know, when we talk about organics too, organic options in this question, we have to also talk about cultural controls, and that's gonna...

I think what happens when at least to me when you go organic, there's no way to spray through that.

Spraying is just part of the picture.

Whereas in conventional, you know, where you're throwing toxic poisons at these fungi, it's a whole different ball game.

When you go organic you've got to consider not just what you're going to spray, what options you have for spraying, but also what kinds of cultural controls you're going to implement.

And even, you know, if you haven't started out yet, what varieties you gonna grow.

'Cause that can make a huge difference.

Your life can be a living hell if you choose to grow chardonnay and- - Grow a vineyard in the woods.

- In North Carolina, you know, organically.

You're gonna be picking black rot berries off by hand to try to control it (laughs).

- I guess yeah, the take home there, 'cause Bryan, I think you hit it on the head there in that regard is whether you're conventional or not, integrated pest management and using every tool in your toolbox to make the most out of everything you do.

And then always having to balance your time and labor and energy and what you have.

But yeah, I mean even in conventional it's like, you may spray the right product at the right time, but if you're not getting good coverage 'cause you've got a monster canopy that's never been taken care of, it's not gonna work as well for most products.

So it's like that cultural is really important too.

And then removing all that and as much inoculum through sanitation practices as you can.

It's just another thing that can help over time at least a little bit, so.

- Well this is a great discussion.

I want to thank everyone.

I think what we'll do is we'll move on to the next pre-submitted question.

And then if we have time at the end we'll answer.

There's been some good questions come in through the chat and I thank everyone who's answering some of those the Q&A or chat.

So Michael, let's see here, this question, we have Michael first.

Alright, I'll go ahead and copy it and paste it in the chat.

The question is, is there a way to differentiate between red blotch virus and nutrient deficiency?

When I pulled out some young vines that I thought were infected with red blotch, the trunks near the ground looked like there were clumps of pale lumpy tissue.

Is that an indicator of red blotch?

And Michael, do you want me to share my screen to share?

There was some photos associated with this question.

- Sure if you want to.

Oh okay, I was wondering what that was.

- Okay.

- Yes, just so everyone on the audience knows I haven't looked at these closely, but that's a great question.

And as grape growers, you know there's lots of things that can be affecting our vines when we drive down in the evening and go, hmm, something doesn't look right and we start trying to be grape whispers, right?

And think about what could this be? Is it biotic in nature?

Is it abiotic? What happened?

So this is kind of a two part question because the grower has scouted the vineyard, they see something wrong and they're trying to determine with their visual senses, you know, what it could be and thinking about things here.

So when we start talking about red blotch, there's the word red.

And so sometimes we see something red in the vineyard and we go, oh my gosh it's virus, you know, I've got it.

And so let's talk about the second part of the question really quick.

And that is, you know, seeing this kind of lumpy tissue when the grower was pulling the vines out.

Let me look. Yeah, can you keep that picture there?

Okay, so this is a great picture because that tells me a lot.

If I hadn't seen this, I could have given you a list of 12 things.

But what this looks to me like is the vine...

I don't believe my gut is, this does not look like red blotch to me.

This particular instance, this one thing we're seeing visually, this to me, when you're pulling out those young vines, looks like there were some sort of injury to that vine.

And the vine is responding through trying to seal off that damaged area with this callous type tissue.

Like when we get cut.

And so this could be a number of things.

If you have a weed eater and you are trying to implement weed control in that young vineyard and you nicked that trunk you cause physical injury , that vine may respond with this tissue.

It could also activate essentially crown gall.

Also in Texas at least we have grasshoppers and they love feeding on stems of young vines and we can see this girdling.

Usually that's all the way around the shoot.

And so I don't know if that's that case here.

Also, if it's severe winter injury we see a split or a crack in the vine and we can see this kind of tumor like tissue, hail damage can do the same thing, that's more spotty.

So I think this is more an issue where there may have been some sort of injury of course that can lead to infection of other pathogens.

But I don't think red blotches the cause here.

But that leads us to the second part of this question, which is e equally important.

And that is, you know, when we start seeing something in the vineyard, can it, you know, it can be very difficult to figure out if this is some sort of disease or maybe it's a nutritional issue.

'Cause there can be a lot of overlap with symptomology.

So the long story is yes there are things we can do to differentiate visually to some degree, but through research-based testing or lab testing, science testing with this tissue.

So I'll talk about that at the end.

But first visual, so when you go out to a vineyard and you see red, right?

It could be a number of things.

It could be that physical injury cutting off flow of tissue and you see red leaf, maybe crown gall.

So if you're seeing all your trunks with that tissue and that damage there, it's probably that in my opinion from what I've seen.

But then we can talk about nutrition and nutrition's important.

So the first thing is when you see something in your vineyard, that's why it's so important to keep records, right?

If you're doing soil testing or tissue testing to monitor nutrition, consult those and go, yeah, maybe this is potassium or phosphorus or magnesium.

And yeah, last year I did a test and it was getting low and I had a huge harvest this year.

Maybe know your weather events right?

Are you in the middle of a drought or extreme wet conditions where you might have some transient nutrient deficiencies?

So from the nutrition side, phosphorus, potassium, and even magnesium, in some cases we can start seeing symptoms that may mimic red blotch for example.

But there are some signs, it can get confusing but that might help us differentiate.

So potassium phosphorus really quickly, some visual cues is their mobile nutrients.

And so at least initially you're going to see that those nutrients move to the newest leafs, right?

The babies, and so the older leafs will become deficient first.

So the older, more basal leafs, oftentimes we'll see this interveinal reddening starting just kind of mildly and then getting worse as the season progresses into summer, maybe late summer.

If it's really severe with potassium, we may be seeing actually purple leaves.

and I've seen photos of this and it looks pretty in the vineyard.

But as a grape grower, we're not happy about this.

Phosphorus is similar, it's mobile nutrient.

We might see interveinal reddening and usually though it'll start more in the margins.

Potassium can't do it, but the take home is you can see some visuals, with red blotch and this can get complicated 'cause there are other viruses like leafroll that may confuse you with that.

If you go, I don't think it's nutrients, but maybe it's some other disease like, you know, red blotch or leafroll.

Leafroll, you'll obviously sometimes see rolling up the leafs and we don't often see that with red blotch.

And some cultivars the veins can become red in contrast to the green veins usually observe with grapevine leafroll.

And there's a really good fact sheet from Rutgers Oregon State's been doing a lot of research.

I know there's some pathologists here and virologists who can speak way more to this than I can, that they'll chime in, but I'll post that fact sheet from Rutgers in the chat in a second.

But red blotch, the symptomology there is a little more erratic and it has this more irregular patterns of this kind of blotchy redness.

That can happen anytime during the year.

Usually we'll see it first on the older leafs and then as the year progresses we'll see it spread upwards.

But that's why scouting's so important all year and taking notes, not just going out to the vineyard when it's in the middle of summer and you go, I'm only here at one point in time and so I don't know how it progressed.

So keeping an eye on those things is great.

and something important when you look in your records and go, oh yeah, I started noticing some blotchy red patterns on my leaves, in spring it was real minor and now it's full blown, right?

And so that's important.

I think I highlighted most of the symptoms there.

The take home is, is you could keep records scout your vineyard regularly, and then the thing that is the best thing to do, the thing we should focus on is, yes, visual observations are important, but we have the ability to test our tissue, our soils for nutrition.

So collect your tissues that may be suspect and send them off to a reputable lab for nutrient analysis.

But also we can take that wood that is suspect for possible virus infection and send it off to a reputable disease lab.

And there are a number of those.

And so that's really the best thing you can do.

Although visual kind of gets you concerned.

It's on your radar.

You may have an inclination towards virus or nutritional issues, but long story short, we can get that tested.

And obviously having a vineyard's very expensive.

So knowing what you've got with a fairly inexpensive test, even if you do it every year is definitely worth the investment.

The last thing I'll say is with virus, you know, when you purchase your vines, most varieties now, we're very fortunate, we can get those certified disease free to the most rigorous standard currently, which is the 2010 protocol.

And Cain and I are fortunate to serve our growers on the National Clean plant network.

And so we are very big proponents of if at all possible, do everything you can to get the cleanest material and that currently is to the 2010 protocol.

So if you had that, yes virus, you know, we can talk about transmission and things like that, but starting off with clean material is one of the best ways to help minimize the impact of virus getting into that block.

So if you bought your vines, you don't know where they came from, it doesn't look like nutrition, you know, having that history, yeah, it could be red blotch, and that can be problematic, but get that tissue test get it sent off to a lab.

Okay, I'll leave it open to my colleagues, especially those who have done a lot more work than I have in this regard.

- Yeah, I'll add some things to what Mike has said.

They are all spot on.

The first question I ask people when, you know, I get a call to say, well, you know, I'm seeing some red leaves, you know, should I be concerned about leaf or red blotches?

You know, what is the extent of, you know, the symptoms on the field, you know, if you have otherwise healthy vine based on, you know, previous seasons observations and all of a sudden, you know, everything, almost every vine, you know, is showing red.

That's a very good indication that it's probably not something biotic because you know, most biotic causations are very progressive in nature.

And so a lot of, some of the things that, you know, Michael has mentioned will come into play, you know, abiotic factors that will affect all the vines, you know, uniformly, you know, will be something to consider.

The other thing also is the time of the year.

You know, and Michael alluded to these, so by the nature of both, you know, red blotch and leafroll even though the vine is infected, you actually don't see the symptoms throughout, you know, the entire season.

You know, so you begin to see the symptoms, you know, around, you know, late spring, you know, to early summer, which coincides with, you know, onset of berry ripening.

And so if you're seeing, you know, those reddening, very early on, that's probably an indication that you are not dealing with the red blotch situation.

So, you know, again, don't get me wrong, you know, if that vine is infected, you can detect the virus, whether it's leafroll viruses or red blotch throughout the year, but the symptoms actually will not express until you know, something that coincides with the onset of rising towards the end of the fall.

Which basically means, you know, when you want to scout for either leafroll or red blotch viruses, you know, you want to actually wait until later in the season, you know, to scout your vineyard for those.

Cultiva will also come into play, you know, vinifera vines, you know, reds will definitely, you know, show leafroll or red blotch symptoms, you know, later in the season.

But a lot of our hybrids that we grow in this climate as well as the American varieties, not all of them show symptoms, you know, and with the hybrids actually, you know, the more Vitis vinifera background they have, the more likely that they'll be symptomatic.

But the less vinifera content you have in those cultivars, you know, the less likelihood that they will show symptoms even though they are infected.

And obviously if it's a wide variety, you know, you're not going to see, you know, symptoms of reddening.

It doesn't mean the virus is not there, it is just that, you know, they don't express, you know, that particular symptomology.

So bottom line, you know, just like Michael said is know, you know, it's taking everything into context.

You know how sudden you know you are seeing those symptoms, you know, what is the scale in the field?

What kind of cultivare are you growing, what time of the year are you seeing the symptom?

And of course, you know, ultimately, you know, if you are really, you know in doubt, you know you want to take that sample, send it to a reputative diagnostic lab, and they'll be able to figure it out and send you the results.

- Great, Michael, Femi, thank you for the answers and the conversation in response to that question.

And thank you for that question in the photos.

We are going to move on.

We got a few more to get through until we're through all of our pre-submitted questions.

So this next question, and I think this is why we're getting so many questions about other modes of action and copper and interest in this is this question that I'm about to ask Sarah first is, let me go ahead and post it, which is, should I be stocking up on as much Mancozeb as I can get right now?

- Well that's a fun question, because we still don't really know what's happening with Mancozeb, before we jumped on this call, we were talking about some news that Katie had just gotten from...

That they're changing some of the regulations that are happening right now.

But again, as far as I know, we've still gotten no updates on Mancozeb specifically.

But if they do pull it off of grapes, if they pull the registration off of grapes, in theory they could pull it and you can use the rest of your stock.

But they could also say that you cannot use it on grapes anymore at all.

And so if you stock up, you only have grapes that you could potentially use your Mancozeb on, you potentially could just be left with all of that stock that you'd then be trying to shell off.

Instead of just being able to use what you have in stock.

So that's a risky game that you'd be playing, but again, we still don't have any updates on where that ruling will go.

- I'll interject real quick too from an economic standpoint as well, is if you buy enough for 10 years, right?

Even if you could use it, we talked about life, you know the viability of that product, it's expiration data or maybe it doesn't work as well.

So another thing, if you're a small vineyard and you've got a pallet of the stuff and even if you can use it, it's like you're probably wasting a lot of your money there just 'cause it may not be good way down the road.

- Good information. Thank you Sarah and thank you Michael.

Anybody else before we move on to the next one?

Which I'll start with Charlotte. I think.

- Justin said this but then you also have to pay to store it so I don't know.

I mean there's a cost of...

I don't know how much we're talking about stockpiling here, but it's just, yeah.

- I'm gonna make a bold statement and just say no, do not stock up.

- [Michael] That's the short answer.

- Good. Alright, thanks for the question.

Thank you for the answers.

Alright Charlotte, we will start with you, and if anyone else here has anything to weigh in on, that's great.

So have any growers had successes incorporating teas with antifungal properties?

- So unfortunately in the vineyards that I've been working with that have used these antifungal teas, no, they have not seen a lot of strong or consistent efficacy.

Part of this is because you're basically making a tea of random bacteria and fungi that are in whatever you're using as your start material.

And that's not very consistent.

And then you also have variable environmental conditions.

So every time that you make these applications you're getting different temperatures, different stressors, you're getting different populations that can form on your clusters.

So you have all of these like grand unknowns.

It's kinda like when you make kombucha on your like kitchen counter, who knows what fell into your scoby.

So your kombucha can taste different every time.

That's the same thing that's happening with these compost teas.

So unless you are doing something to keep it consistent, which would be very difficult and it's very difficult to keep a really nice consistent supply, you're gonna end up with really variable responses and generally not very good outcomes.

At least in the vineyards that I have seen.

When I've been working here in Colorado, we don't really use these compost tees, mostly because our UV index is just so high that it's really difficult to get a lot of these colonies even to establish.

And when I was working in Virginia, you run into that problem of how much pathogen you've got out there.

So like if you have high quantities of pathogen, it's pretty easy to overload some of these things so it doesn't seem to work as well as we would really like it to work.

Especially when you have these alternative products that you can purchase that are generally the same kind of concept.

You're trying to colonize your clusters, trying to get these living organisms to like fight off the bad guys but you know exactly what it's gonna be and it's gonna be more consistent every single time.

Another thing that we don't always talk about with wine grapes because our wine grapes are going through a kill step, is the food safety aspect.

So these teas are kind of a food safety nightmare considering what you're spraying out there, you don't really know what it is, you don't know what those bacteria are.

But if you're growing wine grapes, technically depending on the state you are in, you could be within the law.

Not so much when you're going into products like juice, table grapes, raisins, things that are gonna be eaten fresh or may not be going through the kill step of alcohol.

And there also were a lot of, at least in the state of Colorado, most of these were based on federal regulations.

So check your own federal regulations.

They're tightening down on a lot of these food safety rules as well, so we had to provide sale of all fruit going through kill step.

And if we did not provide the sale for that, we had to show where it was destroyed.

So it's going to make it more complicated if you're trying to do those things and it could be very difficult if you're gonna add that food safety component on top.

So I personally would probably stay away from it.

Anyone else have anything to add?

Because it was really negative.

- I guess I should probably add, we did do some work with compost tees quite a few years ago about, oh, 20, 25 years ago.

And we tried a number of different teas and we did see a little bit of control of powdery mildew I think with them not really of any other diseases.

In, you know, greenhouse trials and out in the field.

So it did work to some extent, but it was a lot of work to put these things together and you know, like Charlotte mentioned, the parent material you use for the compost and the tea that you make from it could make all the difference.

And if it's not consistent, or if you just have the wrong combination of microbes, you could be beating your head against a brick wall for years trying to come up with something that actually works and is very effective.

Whereas a lot of the products that are already out on the market, they've done that work already.

And they've found the biologicals that do seem to provide some control of fungal pathogens on the leaf and fruit and those would probably be a better way to go.

- Excellent, all right Charlotte, thank you for the answer.

Bryan, thanks for the follow up.

and thank you for the question too.

We will move on to the next question, which I will direct to Tim first, which is how important is cleaning pruning material or remaining grapes from the floor of a high cordon vineyard?

We have been told to leave and chop with a mower for nitrogen.

- It depends really on what the situation is with the vineyard, how old the vineyard is, and how much inoculum is in the vineyard I would say.

The main thing, at least from a disease perspective, the main thing that's overwintering on pruning material is gonna be Phomopsis.

I mean there's gonna be some amount of downy mildew, probably some amount of powdery mildew as well, but relatively speaking that they're not producing the majority of the inoculum like those downy powdery mildew, not lots is overwintering.

It's really the explosion they go through.

They're what's called a polycyclic disease.

So they're going through like an initial part where they'll get a colony going and then they'll make lots of spores or sporangia later.

So early season control or dormant things don't really have as much of an effect on powdery and downy.

You can spray all the dormants or get rid of all the material in the world and they just don't have as big of an effect.

But for things like Phomopsis and black rot, they have more of an effect because they're probably somewhat polycyclic but they're more monocytic in nature.

It takes a while for them to generate their inoculums.

It takes a while to develop this Pycnidia or this structure and then this Pycnidia can continually ooze spores as they go.

the vineyard floor...

So the only difference between them mostly is that Phomopsis tends to overwinter on sticks and black rot tends to over winter as mummies.

So having a clean floor in a vineyard in a high wire situation will be good, especially if you experienced a lot of Phomopsis.

But probably also if you've experienced a lot of black rot too.

Because you know black rot survives not just on as mummies, like you'll find black rot Pycnidia also on old rachises too and other things.

It's not just on the mummies.

And probably there's some amount that are on the sticks too.

We just haven't quite, you know, the majority we see it on the mummies.

So if you've had a lot of issues in the past or you're growing a really susceptible cultivar or have a really soft program where you're gonna try to grow organically, it'd be really good to probably remove the pruning material because you really are gonna struggle managing Phomopsis and black rot during the season.

So it's a good cultural practice and probably worth doing to get rid of it completely, burn it, you know, like remove it from the field assuming you're having a hard time.

But if you don't seem to have a lot of Phomopsis and black rot in your field or you're growing a resistant cultivar, it may be all right to leave it and let it decay.

You know, maybe prune and then and mulch it.

You might not have as big of an issue that particular season but it's probably something you have to keep monitoring every year to see if you can do it that way.

'Cause you are effectively leaving Pycnidia in the field if you leave a lot of green material around.

It probably matters a little bit of like when you do it too.

So if you did it earlier in the season before the grapes have started to leaf out, that gives them some amount of time to decay a little bit more, chop it up more finely.

Same thing also it has a little bit more time to decay.

I don't know if other colleagues have thoughts on that.

- I'll have a little bit.

And this is something that might be situational.

If you have very high mealybug infestation levels, you probably want to pay attention also, you know, to, you know, your prudent materials, you know, especially if you observe know very high numbers of mealybugs, it's fairly crawlers.

The last thing you want is, you know, to prune and have some of those, you know, walk back or move to neighboring vignettes, you know, so just wanted to add that, you know, mealybugs are vectors for leafroll viruses and so that will be something to keep in mind.

- All right, thank you Tim and thank you Femi.

And thanks for the question too.

So we have two more questions to get through and then we will take, hopefully if we have time, I think we'll we'll go through to 1:35 Eastern time.

We started a little late.

There's a couple questions that came in about late season fungicide applications and how that might impact fermentation and the timing of those.

So I think we should get to those.

I do wanna thank everyone for asking questions and also my colleagues here for answering so many questions on the Q&A.

So there's more information if you just look at the QA&.

Lots of questions and answers there too going on in addition to what's just being vocalized today.

Alright, thanks again. So let's see here.

This one I will direct towards Bryan first, which is, any new information on how to eradicate crown gall in an established vineyard?

- Not that I know of (chuckles).

Crown Gall's been a really tough one.

There have been lots of efforts to produce clean material from other vines, you know, from nursery and it's proven to be harder to get crown gall out of planting material than to get viruses outta planting material.

Whether that'll be accomplished at some point, I don't know, to my knowledge it hasn't been yet.

So right now it's impossible to start a vineyard, I think with crown gall free material.

And part of the problem with the whole issue I think is that it's such...

The pathogen causing crown gall is so ubiquitous that even if you started with a spanking clean vineyard vines that you know, were clean of crown gall, you would eventually get it in there anyway.

it's in the soil, it's on other plants, it's on plant surfaces and it just takes an injury for it to get in and become systemic in the vine.

And now the vine's infected for life.

We, you know, what I will say however is that, and this is the reason I was asking earlier before we got online with the group that Misho Nita has done or was planning to do some work with a rhizobium or an agrobacterium vitis that was non-pathogenic, non-tumorigenic form of the crown gall bacterium.

It was developed I think in Japan years ago.

It's been tested there for many, for at least a decade, probably a lot longer than that.

But it's shown a lot of promise.

It's called ARK-1, and there've been a number of non-pathogenic, non-tumorogenic rhizobium or agrobacterium, it's not even rhizobium anymore.

I think it's been changed again, so I can't keep up with it, but it's the same pathogen.

Anyway, it's a non-tumor genic crown gall bacterium that seems to inhibit, you know, the tumorogenic crown gall bacterium.

And you can inoculate nursery plants with it before they're sold.

You can basically by soaking the plantlets, soaking their roots in a solution of this ARK-1.

And the ARK-1 will colonize the root system and protect the plant to some extent from the damaging effects of the tumorogenic crown gall bacterium.

And like I say, there's been a fair level of success and to me, at least from what I've read, a lot of things have been tried over the years.

This seems to be the most promising thing and it's, I don't know, maybe somebody in the group here knows if it's being sold commercially yet, if it's at that point, I don't know.

But the results of this look to me over the last 25 years that I've been in this monkey business that it's the best thing I've seen for treating and dealing with crown gall, aside from just what we already know in terms of healing up around grafted vines to make sure when crown gall does kill the upper part of your vine, you have something left from the scion to bring up new vines and deal with it.

Up here, we, you know, in the great white north, we just deal with it every year.

I've got a Riesling vineyard that has been in the ground since 2016 and there isn't a single trunk there that's more than three years old.

It's just a regular...

It's a fact of life.

We deal with it every year, crown gall.

But I'm hoping that the ARK-1 thing pans out to be bigger and bigger as time goes on.

- I can add a little bit of context for that.

So I did spend a little bit of time working with Misho in his lab.

Unfortunately they were running into issues with, it was a non-native species so you'd have to import it and having to get all of the regulations to allow us to have a non-native species being released in our vineyards and the safety regulations that went into that.

So at one point he was transitioning to see if he could find native streams of Rhizobium that did similar things, but I don't really know what the success of that has been.

I've been out of his lab for a while now, so I don't really know how far that's gone.

But that was his goal was to try and bypass that whole logistic nightmare.

But it was very promising.

So maybe some chemical company can come along and start funding some of that pain.

- All right, thank you Bryan and also Charlotte and thank you for the question.

So the questions I mentioned earlier, you lead panelists are just ACEs at answering these questions.

So again, please look at the Q&A if you haven't, there's been some great questions and great answers from the panelists here today.

So this is the last pre-submitted question, and then I think we'll answer one of the others, one or two of the ones that were asked today if there's time.

So this one I'll direct to Sarah first, which is how much should I be worried about sulfur phytotoxicity in the vineyard?

And maybe as a side question, it's when should I be concerned about sulfur phytotoxicity?

- Yeah, so sulfur phytotoxicity is generally considered a function of both your temperature, very high temperatures as well as very high relative humidities.

So it's when you have both of those things and the exact level of where those need to be in order to cause sulfur phytotoxicity can vary in which case generally a lot of the research is focusing on like upper 80s and about at least 70 to 75% relative humidity.

But it's also very much a difference on what cultivars you have.

If you've got vinifera that's gonna be very different than if you've got Norton and some of the other American hybrids that can have a lot more sensitivity to sulfur.

I'll mention some of the tests that the recent graduate master student Walt Sanders with Phil Brandon did here at UGA.

Looking at spraying mostly on vinifera.

We tested a few of the hybrids but spraying the highest labeled rates of sulfur on vinifera vines.

We tested several different cultivars and he sprayed it either at 3:00 PM on days that were supposed to be really hot and humid and then also at 7:00 PM.

And on the vinifera we really didn't see any phytotoxicity and that could be attributed at least to the sulfur use and then he went back and dug through some of our historical weather reports and even in Georgia, which this is in the mountains of Georgia where our vinifera is, but we really very rarely hit those like upper 80s with very 70 to 75% high humidity time periods.

So that really didn't occur as often, which is hopeful for potentially using that a little bit more often.

But we did definitely see it when we tested some of our other hybrid cultivars.

Here a little bit further south where we had, some on our Crimson cabernet, which is Norton, a child of Norton that we sprayed.

And we definitely got a lot of phytotoxicity and definitely higher phytotoxicity at 3:00 PM versus the 7:00 PM application.

So at least one, if you're testing something that you're not sure about, you also make sure that you're doing a pretest and you're also doing it in those conditions that you might be spraying that in.

Because if you test something early in the season when it's nice and cool, that's very different than if you're spraying it later in the season when it's hot and it's humid.

So you always wanna test that in those conditions.

But also if you're worried about some of that, you can also try spraying either like really early in the morning when you've got enough time to dry out or later in the evening where you've already passed the hottest part of the day could also help reduce that risk for any phytotoxicity response from those vines.

And that's just a quick rundown of those trials since we're getting on towards the end of that, but.

- That's great.

Thanks Sarah.

So we've had a couple questions come in that I actually don't think made it over to the Q&A.

if they have, please correct me, but again, there's lots of information in that Q&A area, but one was, does anybody know about the effect of adding foliar fertilizer in a tank mix, and if that could augment fungal, you know, fungal pervasiveness or would if it would help fungal diseases thrive?

- I think it depends a little bit on what they mean by foliar fertilizer.

So if they're talking about like potassium phosphate, then sure, I mean it's a fungicide and it's a foliar fertilizer.

So I think that's just something to think about.

Like what do they mean with foliar fertilizer necessarily.

Generally though, like for powdery mildew that the healthier a plant leaf is, like the more green it is things like that, it's actually gonna make disease potentially worse because powdery mildew thrives on really lush green tissue situations.

But there are some examples on foliar fertilizers like phosphates that like I think we've had some really good luck with zinc phosphite, which is definitely a fertilizer but you can get it and it's actually not a bad fungicide by itself, right?

- What about nitrogen?

What if you were looking to apply a foliar nitrogen product?

- I think it'd make powdery worse is what I'm trying to tell you, yeah.

- I think it can make detritus worse too possibly, especially later in the season.

- Yeah, and sometimes folks are trying to think about ways to make the vineyard more healthy and giving it more nutrients is not necessarily gonna make the vines more healthy but it can provide food for the pathogens sort of.

- Yeah, I think there was some work done at Cornell years ago to alleviate low yeast assimilable nitrogen at the end of the season.

So they made applications of foliar nitrogen and I believe they found that it seemed to exacerbate a bunch rot problem.

So I don't know all the details of it but it was a bad thing.

- Gotcha. Yeah.

- I mean if you think in some ways if you stress a grape you'll probably make it a little bit resistant to diseases.

I don't know, there's probably research on there.

So there's a lot of deficit irrigation that they do out west that probably will slow disease a little bit because you're stressing the vine essentially.

I mean I don't, you know, it probably depends a lot on the situation and the cultivar but you are stressing the vine and a lot of the stress responses that grapes...

That any plant has usually make disease go slower in a plant.

- Great, one more question and then we will part ways and wish everyone happy spring, especially on a day like today.

'Cause this question came in, I don't think it's been answered and I think it's a good opportunity to just visit some fundamentals about disease management in vineyards and the question was incur...

Maybe it's been answered, but do you have to spray as much with one and 2-year-old vines when we are not expecting fruit?

And so I think especially for those that are new, add some context here about, you know, what you need to be concerned about when you have fruit versus not fruit.

- You don't need to be concerned about bunch rots if there's no fruit.

Sorry, that's maybe an obvious, but that's like.

- I thinking to myself of like little vine, less canopy, less spray.

- No fruit.

(panelists laugh)

- Indeed you do wanna make sure you're keeping leaves on those vines though.

- That's a good point yeah.

- Yeah, don't let downy get outta control 'cause then there here goes your little baby.

- Indeed, like plants don't grow very well if they don't have any leaves.

So keeping a canopy out will definitely help make sure that those vines continue to grow.

- We don't normally see a lot of black rot Phomopsis on a young planting either.

So I would say most of...

Unless they've just had a vineyard in there before.

So I'd say it's all about what everybody else said.

Not letting the canopy just completely die.

- But what are some good current chemicals?

Not thinking about anything in the future.

What's a good spray program for a nonbearing one or 2-year-old vineyard.

- Mancozeb sulfur, for over and over and over and over and over and over again (laughs).

- You could probably throw in a little bit of Captan.

- Yeah.

- [Tim] Bit of captan in there for sure.

- Mancozeb for me (indistinct).

- If I may add something.

If you have surrounded by other vineyards, you probably want to protect those younger transplants, you know, by putting some systemic, you know, materials against mealybugs and scale insects.

So we are slowing the virus spread.

- Yeah, we have issues too. This is a canopy thing.

It's just an insect thing to echo, I know that Japanese beetles generally don't cause a big issue once the vines mature.

I have not found that to be the case for little vines though.

It's probably worth spraying an insecticide just to make sure you don't lose your leaves.

At least at my own research vineyard, that's what we've had to do is spray for Japanese beetles.

- Well I did wanna say one more thing.

- [Cain] Oh yeah, go ahead.

- I mentioned Mancozeb sulfur, only to sulfur tolerant varieties.

- [Tim] Oh yeah.

- Yeah, if you're growing concords, no, don't use sulfur.

Find something else for powdery mildew.

- Good point.

Well Bryan, I'm glad you did speak up there because it reminded me that I wanted to say something Tim just reminded me about, which is Bryan's been at Penn State for 25 or 26 years.

Bryan will be retiring in June.

And I just want to take this moment amongst all, many of his colleagues here, his great pathology colleagues to thank Bryan for such a wealth of information and congratulations on a wonderful career.

I had the pleasure of working with Bryan when I was an undergrad back in '07, '08, '09, and Bryan inspired me to go on and pursue great research.

So Bryan, thank you so much and congratulations.

- Congratulations Bryan. We'll miss you very much.

We're a small community, and you've been such an important part of it.

- That means a lot to me. I appreciate it.

- [Tim] Thank you Bryan.

- Okay. Alright, well thanks again to our panelists.

Again, if you want to give an applause emoji or just say thank you. I know many of you had.

But thank you so much to each of you.

This has been a really informative webinar and happy spring to everyone.

Good luck finishing pruning and good luck with a really smooth transition from dormancy into the growing season.

- We've hit blood breakdown in Georgia.

- Wow, we're almost there.

- [Tim] Don't say that.

- [Sarah] We're not even done with pruning.

(Cain laughs)

- Thanks Cain for all you do, we appreciate it.

- [Sarah] Thank you Cain.

- [Tim] Thanks Cain.

- Happy to do it.

- [Bryan] Thank you everyone.

- [Time] Bye guys.

- Take care now.