Scaffolds 2024 Digest: Week 8
This post is a text digest of the Scaffolds Podcast. To listen to the original episode, visit the following link: Scaffolds Podcast on Spotify
Monique: On this week’s episode, I talked to Scott Palmer from Reality Research about a pre-bloom woolly apple aphid trial. Kerik gives us the disease forecast and tips for post bloom fire blight management, and Anna gives us our weekly update on degree day accumulation and pest detection.
Monique Interviews Scott Palmer from Reality Research
Monique: Okay, so today I’m here with Reality Research, Brad and Scott Palmer. These are my colleagues, and we’re working together this summer. And this year I got a crazy message from them in the last week of March saying, hey, I think we have woollies. And I went out there and took a look, and sure enough, we did have woollies. So, hey, Scott and Brad, you want to comment on finding woolies in the last week of March?
Scott: Well, first of all, I didn’t want you to find woollies. I wanted them to be dead because I didn’t want to worry about them. But being the professional you are, you actually did come out, and we truly appreciate you going very much in the extra mile and doing the testing to find out that, indeed, that we had live woollies in the trees in March, that they had overwintered there. We had seen things on the internet from other places in the country, we talked to other people in the country, finding out that this is not necessarily such a new thing in many of the areas just with us as the mild winter that we had, we seemed to definitely have a population that we didn’t think would be there.
Monique: Oh, well, this is just a testament to our good communication throughout the season. So, do you think this is really just due to the mild winter? Do you think it has – could there be any other causal factors from your perspective?
Scott: I think that’s a great question. The truth is, I don’t know. I think a lot of scouts, consultants, growers assume, rightfully or wrongfully, that we didn’t have a problem early, and this may be because of the parasites that are in our orchards that time of the year that we haven’t interrupted, and they might have been controlling anything that had gotten through, just as we don’t normally see woollies as a farm problem or normally as a spot on the farm problem, and I think that’s largely due to having parasitoids out there to help do 90% of the control.
Monique: So do you think that they were really active in the post season, post-harvest time? Is that what you’re thinking, you know, when there’s not a lot of treatments going on?
Scott: Well, I do think that last year’s abundance of woollies was largely due to the freeze event. We had the May 18 event that destroyed probably our parasite population, therefore, letting the woollies just run rampant from some of the trial work we’ve done this year, early in conjunction with you and having ideas of what we’d like to try, we would say now, probably one of the things that we’re doing later in the year that’s creating us having problems with woollies is we probably are killing those parasites to an extent with some of the other chemistries we’re doing.
Monique: What do you think are those other chemistries? You think it’s pyrethroids?
Scott: Yes, could be pyrethroids. You know, the harsher pyrethroids, bifenthrins, you know, things like that. To say that it’s only those. How would I know? We haven’t tested things like that before. Maybe that’s something that you might be looking at in the lab.
Monique: So this trial that you guys ran like, yeah, I was involved, but I was traveling, so I couldn’t come and collect samples, which is disappointing, but I think the trial is unique. Right, so that was one of the reasons that you guys decided to put it out there was because we actually don’t know the answer to what to use pre petal fall, all the recommendations are for petal fall. So what does the trial look like? And did you think there were any promising products overall for that early season usage?
Scott: So, again, that’s one of the things we wanted to try to do, was what is already able to be used and what could potentially be used that time. Again, as researchers working with you, when you said, oh, yeah, they’re alive, and we went, oh, man. Well, we got to get out there. We got to get going. And not, not to throw jello at the wall, but have some sort of consistent ideas of what would happen. And we also had growers and consultants tell us that there were some things, some growers that didn’t have a big woolly pressure last year compared to other ones, including us, that had terrible ones. So we did wonder if some of the things we were putting on, like, say, for scale early, such as Esteem, maybe they are helping control that, even though we’ve never looked at it that way. We tried other things, you know, whether it was a Neemix or M-Pede. We did look at a Sefina, a new BASF product that just kind of came out, and we don’t really know a whole lot about it. We certainly don’t want to use one of the two applications we can use at that early if we don’t have to. But we thought we ought at least see, is it a potential. So we did do these applications. We did two evaluations on them so far, one about six days after the applications were put on, one almost a month later. And what we’re finding was almost anything we threw at them early knocked down the population. What was very interesting was Esteem ended up having even no eggs on the trees. We didn’t know that there should be eggs on the trees, and actually, all the other treatments, including the check, had eggs on the trees. But Esteem actually worked very well, not only knocking down the original population on the first evaluation, but we had no live or living woollies or eggs on that treatment. And it was just a regular Esteem treatment. So otherwise, Sefina, I would have said came in probably second, but it knocked them down early, but not as much as we thought. But we’re talking a week, and we would say that Safina, that’s normal. We had nothing alive, but there were eggs there. So again, you know, that if there’s eggs, we can still have a population. M-Pede was probably after that with Neemix, after that other stuff we looked at, they were not going to be better. In fact, we saw some things that we could say that were detrimental to the check of, you know, the parasites coming in and helping control.
Monique: So when you were looking at these early populations, did you see any winged aphids?
Scott: No, we did not. We did see some predator mites, which was awful early that we thought for seeing them that time of the year, moving around and shaking. But as far as the Mali that you normally talk about, I would say we didn’t see that. We do see evidence of them in the checks with, uh, the shells with holes in them and like that. But other than that, no.
Monique: Interesting. So Esteem is an insect growth regulator. Do you think there’s other potential insect growth regulators out there that might be worth investigating?
Scott: Yes, I would assume. Researchers have never used the word assume, but we wish we had tried Centaur, because that’s another one that’s recommended early. We know that Centaur was used a lot, though, last year. And again, a lot of growers had woolly problems. So I think it would be needed to be tested to know if it would have a positive effect without hurting the parasitoids, too. Right? Because it’s a double thing, right? You got to have something that works on the woollies, but also doesn’t hurt the beneficials. So, you know, we didn’t check that. So that’s the next year thing. Unless you can do that in the lab to give us some preliminary information on it, that would be great.
Monique: Well, we’ll see if that colony takes off. I got them to initiate, but I’m not sure whether they’re going to spread to our other trees that we’re trying to keep them on. So, I guess my last question is about water volume at this time of the year. So, what water volume did you guys apply at? And did you feel like it had sufficient coverage?
Scott: Brad said we did it at 100 GPA. That is not normal, that time of year. But we wanted to give everything its best shot, I guess, is the way, I would say, where we’re seeing these populations are not on nice, clean branches that are healthy. These were ones that were severely damaged the previous year where it actually split the bark. The tree tried to reheal in its spot, making, you would think like scars, if you will, trying to heal up. And so there’s all these little nooks and crannies that they’re stuck in. So, in fact, Brad did put an adjuvant even in with all these. Again, normally that time of the year, you wouldn’t necessarily think to do that, but we just, because this was such preliminary information, we thought we better give it its best opportunity for success.
Monique: Okay. Yeah, I mean, we’ll have to see how this progresses. You know, with our luck, I think we’ll have a not-so-mild winter next year and not get to try it again. But, yeah, definitely thinking about trying stuff in the lab, I think is worthwhile if I can get this colony to establish. Thanks so much for talking to me today. And we’re about to get our petal fall spray out here for woollies. So data will be being collected!
Scott: Yep. Thank you so much for all the hard work that you guys do and working with us. It’s nothing but a positive for us.
Monique: Positive for me, too. We are happy to be out there with you guys and not managing our own crop for horticultural purposes to use for testing.
Scott: Thank you, Dr. Rivera.
Monique: Thank you.
Pathology Updates with Dr. Kerik Cox
Kerik: Okay, let’s look at the weekly forecast. It is Mother’s Day, 5/12/2024. And we’re into another week of constant rain. Speaking of rain, let’s talk about apple scab and likely the other fungal diseases. I think it’s going to be a tough year for fungal diseases, particularly apple scab and apple blotch or Marssonina blight, whatever you’d like to call it. At this particular stage, we’ve had a lot of rain, and it keeps coming with no sign of lighting up. It’ll be interesting to see how Memorial Day plays out, it’s been cold and wet, cold and wet early is very favorable for apple scab, and cold and wet a little bit later after petal fall is very favorable for Marssonina or apple blotch.
So let’s see how this week is going to stack up. Let’s start in Riverhead, Long Island. Hopefully the primary scab season is over, but it’s been wet enough that I would still consider looking at infection events over the weeks to come. They’ve lost all the ascospores. There could be conidia out there and sometimes I might like to peek ahead just to get a magnitude, yes, we’re talking, we know that the ascospores are ejected. I always like to maybe move that green tip date up, let’s move it up 20 days just to be wild and look like anything is actually changed. It is all gone. All right, well, all that being considered, let’s see. It looks like the next big event coming up is on May 14th through the 16th. And it looks like over the weekend you’ve got some fairly dry weather. I think at this point you can go ahead and maybe consider moving into a couple if you haven’t already used all your single sites. If used a lot of them don’t spray anymore and just stick with protectants for this next period. It’s a considerable bit of leaf wetness coming up on the 15th through the 16th, three days. Doesn’t look like you’re going to get a break if you’ve had a wet last week, I would go ahead and protect up going forward at this particular instance. And now you’re at the time where you can get a lot more out of your single site fungicides for powdery mildew, apple blotch, apple scab, and even weird latent diseases like Colletotrichum. So if you haven’t used them all up, put one in now and start the summer off right. How does your fire blight look? Fantastic. Um, easy fire blight season. It’s been a whole season of probably pretty easy weather. Let’s take a look at the whole cougar blight risk graph. Yep, it’s just been green the entire bloom season. And if you still have trees in bloom and it looks like you might, um, continue watching the weather, this is a season where you can just get away with using biologicals the entire time. No need for complicated double-antibiotic tank mixtures. I think you can do well with the consumer-favored biopesticides. Right now you’re looking at TRVs in the 13. Your EIPs are yellow with maybe one high day coming up, probably suggesting. Yep, and our daily average of over 61 on the 16th, but it’s still a zero EIP. They can’t accumulate enough heat hours to do to get any flower infections.
Let’s move up into the Hudson Valley, where things have been a little more challenging for all diseases, my opinion. All right, let’s take a look, all right, yep, there it is. Just like Geneva and everywhere else in the state, it has just been one constant rain event. It looks like you might get a break. It also says all the ascospores are gone now. But also you’re now moving in the petal fall, moving into thinning, and, um, coming into more wet weather. You might get a break on the 13th coming up. You might be able to get enough dry weather to get in there, and I would go ahead and include a single site. And at this point, as you’re moving into the thinning weather, I’d say we back away from Captan and go single-site with Mancozeb while you still can. If you’re still 72 days from harvest, I would go that route. So the 10th through the 12th is just a constant infection event, like here in Geneva. 13th, you have a break in it, and the 14th and 15th, another little bit of wetting, giving you just a little bit of time to go Mancozeb. In a good single site fungicide, you don’t necessarily have to go the ones that are hard on apple scab. You can include a group seven, some of the Luna products, Merivon. I think at this point they’re gonna have the broadest activity on any powdery mildew, or apple blotch/Marssonina, either one, your choice, I didn’t choose to change the name, someone else did. And even stuff like your Colletotrichum, your bitter rot type things going in right now. Avoid the captan, because we have a lot of wet weather and slow drying conditions. And as you putting in all the other thinners, you don’t want the captan there exacerbate the problem. So Mancozeb and a single site, I recommend for there.
Let’s take a look at your fire blight. I’m always a little more worried about the Hudson Valley. They’ve only had the one area that’s actually had some pretty scary weather. Is it telling you that shoot blights over? Oh, not even trying to predict a first blossom date, well, let’s just pick one. Acting a little weird, right? All right. Looks like you’re coming off of an intense fireblight period. And if you protected the crop into the end of last week and through the weekend from that big heat burst we had the previous week, I think you’re good. This week you’re looking at May 12, which is today, a TRV of 16 green, marginal risk, and epiphytic infection potential, your EIP is going to be zero. Maybe moving in to the, uh. That’s doing some weird stuff, let’s redo that, hit that thing again, it didn’t like to refresh date. I’m just going to pick any. Don’t pick that date. Let’s pick a nice, back in April, again, it’s doing a little berserk stuff. So if you’re seeing this yourself at home, you can see exactly what it was doing, it did not want to select present day and there’s like a little gap in the station on Saturday the 11th for this particular station, a little weirdness going on, but that’s fine. Nonetheless, still shows an easy week of fireblight. Some hot weather coming up towards the end of the week. And if you’re in the dregs of petal fall, um, you know, finish strong. I think you could get by with biologicals, but if you wanted to make sure your blossoms are clean, particularly in your high risk susceptible blocks such as a cider apple, you might want to move things up. And you know, I think if I was going to consider how do I make this stuff look a little more extreme for my different varieties, you can adjust the type of bloom history here and we’ll move up your cougar blight TRV values. And I believe let’s see if it doesn’t do that. Yeah, in this case, if I was, and doesn’t really change the EIP component, but it will change your cougar blight TRV. And even though it’s asking me to increase the risk via orchard history and you see fire blight active, probably get, get by with doing the same thing to see what it would be like for susceptible cultivars. I mean, they might as well have fire blight active in them, but still looks pretty good overall. Barely creeping into the high-risk weather on that 16th with some temperatures over the sixties [°F], but it’s been a very cool bloom. I think you’re safe. I think you could get by with a lot of biologicals.
Capital District, let’s see how their apple scab is looking. Hoping a little better. I suspect it’s going to be wet. I’ll type capital district, let’s type Voorheesville. Let’s check it out. Oh, they still have a few ascospores left. They’re coming into the last little bit of time, much like the Hudson Valley coming into off of a long week of wetting and weekend into the 13th, that’s tomorrow, giving you one break in the action. And that particular instance, you get a little bit of time before going back with another wetting period. So going on that 13th, I’m thinking we’re getting into the thinning period. Move away. Don’t do the captan with all the wet weather and slow drying conditions and go Mancozeb and a single side fungicide, recommending getting some of those QoI fungicides in the mix with a Mervion or Luna Sensation or some of that to make sure that you, um, can pick up any of the beginning components of apple blotch, Marssonina, or bitter rot, and powdery mildew.
All right, let’s look at fire blight in that region. I think it’s probably also going to be safe, Voorheesville, right? Wow. Let’s take a look. A little bit of misbehavior there. Not too much now. It looks like it’s gotten over itself. Looking at the week, some higher weather, a little bit warmer, I’m guessing some warmer temperatures towards the end of the week, just above 60, but not even into the seventies [°F]. Remember fire blight bacterium loves 70 degrees and higher for the most part. And TRVs moving into 100 higher risk. If you really had some stuff hanging on, you could finish strong with an antibiotic. But your EIP, your equivalent thereof of Mary Blight says you’re fairly safe overall in that region.
Moving up to the Lake Champlain in Peru. Let’s take a look at Peru Northern Orchard. Yep, they’re here in the middle of a big ejection event that is happening and combined. Now you may or may not get a break in the action before the rain continues on through the week, but there is a slight dip. I’m noticing in the leaf wetness hours going from 20 to 4. So there might be a chance for you to get in there and do the same as everyone else. Uh, Mancozeb, while you still got it and still can put it on, plus a stronger single site. We want to get through this primary season pretty quickly. A big 19% ejection on May 12 on Mother’s Day, um, for apple scab. Like I said, I think it’ll be a fairly hard year for apple fungal diseases, the bacterial ones.
We’re going to take a look at Peru Northern Orchard, see how that’s going. Looking pretty good. Um, it’s just going to be an easy fire blight season. Don’t need to kill it. You could probably get by with your biopesticides of choice. Um, yeah, you can probably. You’re probably going to escape bloom. I think even if we look at the cougar blight risk tables, it’s. You’re just green across the board, as much what we see in the tables as well. Um, TRV is about 50. I mean extreme gets up to like 400 plus. And then um, your EIP is barely gracing into the high level. And that’s probably because you have one hot day, yep, 63 average is predicted for the 14th. But only get your EIP up to 9, 100 is where you even need to be thinking about being concerned.
Moving into the Finger Lakes area, let’s do Interlaken area. And yep, much like Hudson Valley and the Capital District, you’re going to get a break on the 13th of a little bit of weather, it’s still going to be putting out some leaf wetness. It looks like it’s even showing up to two quarters of an inch of rain. If you can get in there, you’re not in an infection event, you should be able to go in with a Mancozeb and a single site and hopefully take care of this. I’m going to move the green tip date away, I think I won’t be able to cheat the system and get past. It’s not really let me pick it, do anything, it’s not making those apple scab ascospores come back. Pretty much at the end of the Apple scab season as well here, not being able to game the system and see how much is ejected, but I suspect if it were to show me, it would be quite a good bit over the weekend. But now we’re moving into sort of that last little phase where the models don’t predict well and we’re talking about maybe conidial infections. But again, if you get a break in the rain, looks like maybe Monday’s your best day. Mancozeb with a single site fungicide with broad activity against mildew, bitter rot, apple blotch/Marssonina and scab.
All right. Looking at the fire blight situation. All right. Yep. Pretty easy week. It’s going to heat up towards the end of the week, even though we’ve got some hot, warm rain, just a few days where it’s gracing 60, nothing to worry about. TRV is under 100. We’ve just come off some hotter weather at the end of last week, 208 TRV there. But you know, you’re having cool nights and whatnot and it’s dropping your risk for the EIP model down into the moderate. Nothing to worry about. I think it’s another easy year. You can just manage stuff with biologicals.
Let’s move up around the lake, right in the Sodus area. Does it look like there are still a few ascospores hanging on. I’m going to go ahead and move the date a little bit, see what it looks like. Yeah, it’s still, you’re just looking at 2 or 3-5% ejection and you’re in the middle of an infection period. You might not be able to get out. There’s still going to be leaf wetness, still going to be a little bit of rain between today and tomorrow. You might get your best break to get in there and get some coverage with maybe a little bit of Mancozeb while you still can use it, plus all of the single site fungicides. The nice thing about the Mancozeb is it also has rust activity, and if you get that out now, you’ll be able to pick up any cedar rust control. We don’t want to get that captan, too heavy into the thinning window. We can pick back up with that later in the summer if you want to continue to use captan. But when the tank mixes get complicated and you need to increase the absorption of your PGRs, the last thing you want to do is increase the absorption of captan. So let’s avoid that for a while.
How does the Sodus fire blight look? I suspect it’s going to look pretty good. All right, Williamson, let’s take a lip. It’s just solid zero EIPs across the board. You could probably not spray anything at this particular point, biopesticides would just do it well and hopefully you’ll move into the petal fall thinning window.
Niagara area. Let’s. Okay, there we go. I’ll go to scab, in Appleton. Let’s see how we’re doing and pretty much say that the season’s over. I don’t think I can cheat the system anymore, but trying to pick different green tip dates, it’s pretty much locked us in as being done. However, we still want to watch these in case there is a little bit asynchronicity between ascospores in presence or presence of conidia. A big never ending infection event, looks like today or tomorrow, you know that 0.2 inches of rain between the 12th and the 13th might allow you to sneak in and drop another Mancozeb and a a single site for all the reasons I mentioned earlier.
Fire blight it’s just a lot of rain, only one really hot day. It seems to suggest that the 13th tomorrow you’re going to get above 60[°F]. But that’s not even really hot for fire blight. It wants 75’s [°F], and you’re not getting it. You’re in great shape. TRVs are all marginal; EIPs, zero in many instances, 13. Couldn’t ask for a better bloom season for managing fire blight. And then that’s it for both of the two diseases at this point, the apple scab and various fungal diseases which all love water. And fire blight, which likes lots of heat, seems to be doing pretty well this week. I think it’s going to be an easy fire blight season, but I will talk about how to stay strong in the post bloom period with fire blight as shoots begin to elongate. Memorial Day is coming, and along as the side from all the sales, it could actually get some hot weather. And between that time period, that extra heat potential for thinning and a couple other things going on and complicated mixes and maybe storms of some sort, it could lead to shoot blight even if we escaped it easy with a blossom blight. And I’ll be talking about that next.
Okay, it looks like we’re mostly getting through the bloom season. And now continuing on our Fire blight series, let’s talk a little bit about fire blight post-bloom. Now, we’ve escaped this 2024 season with a really nice cold bloom season. Yes, there’s probably still a couple flowers on the trees but right now, even this weekly weather is all very cool, all under 70 [°F]. Fire blight is in a good position to be completely squashed by our growers this year. But the thing is you’re moving into the thinning period. Tiny fruitlets are killed, windstorms come up and heat comes up. We can still get fire blight. So I want to talk a little bit about how to end strong and avoid the post bloom petal fall. And a lot of my trials, the amount of blossom blight if you see the talks at the winter fruit schools, usually mimics the amount of shoot blight. And my blossom blight leads to the shoot blight. But in many instances, a lot of our growers, in most cases, don’t ever submit us samples of blossom blight. We never see it. But we do see lots of shoot blight. Which makes me think there’s some sort of asynchronous development between the two. So even if you had a good level of blossom blight control, all it takes is some really hot, awful warm storms around Memorial Day, as we’ve seen in the past, and you’re stuck with a lot of shoot blight.
So, what do we do? I recommend, since we’re having a lot of rain, and I suspect trees are going to be fairly vigorous. Maybe not from the heat, but from all the extra water. Ours are moving pretty quickly. Ours went from petal fall in our Idareds to like almost little tiny fruitlets. I mean, yeah, like maybe 6 or 7 mm. But that’s very fast considering they went into bloom like maybe ten days ago. They’re really moving along. And in your case, you might have to slow them down. What’s generally recommended is about 6oz per hundred gallons particularly, and this will do fine, and sort of young trees this is, or if you’re really concerned about it, and when another really nice program that really doesn’t really restrict the growth, but doubles up on plant defense inducing is 2oz of prohexadione calcium. Give you a little bit of thickening. And 1oz per hundred of Actigard. You can put that on both the petal fall and about ten to 14 days later. And make sure to just keep that vigor down and keep those internal defenses very, very high as you’re moving into the post-bloom period. All these things work is the prohexadione calcium will thicken the cortical parenchyma of cell walls. And what that means is all the cell walls inside the young developing shoot tissues will become so thick that the bacterium, which makes a little tiny needle to cause its invasion to go and cause its numbers to boost as it invades it, causes its reproduction to go berserk as well. And this thickening just a little bit will prevent that little tiny straw, or pilus, as it’s called in the scientific world, from injecting its sort of biochemical warfare tissues and leading to invasions and increases in numbers. So that’s why you do it at the same time as it’s trying to do all of that. The other material, the Actiguard will be boosting the defenses in these young succulent tissues and stopping it. And of course this slows the growth of trees down a bit, but I think they’re moving quite quickly overall.
And then what you can do is you can avoid the situations like I’ve seen here, this is a shoot that’s completely invaded. And here are a row of young high density trees that I was trying to get established. And we had a hot, windy Memorial Day. Let’s hope we don’t have another one. Aside from that, what you can do is you can put on some post-bloom copper. Usually it’s a protectant only, it can cause fruit russeting, but now there’s a lot of other low MCE coppers that will put a little bit of copper out there to do good. It’s fantastic during nursery or establishment years, if you want to use it, use it with adequate drying time. I don’t know if I would start my copper program now as we cannot get away from constant low-lying areas of rain. I think with all of the rain and constant leaf or fruit wetness as we’ll be coming up, we might increase our chance for plant injury. But just be careful that it only reduces surface bacteria so it needs to be reapplied. And sadly, as your terminal leaf shoots grow, they can grow faster than the copper residues. Hopefully if you’re shutting them down with a little prohexadione calcium, you’ll be able to keep them covered with copper as it might slow them down a little bit. Want to get sort of through this hot period until the trees get moving. Want to get them closer to terminal bud set and you can use, there are several different coppers that have these sort of low-rate fixed copper programs. Seven-to-ten day schedule, not really high levels, ones that mix really well and are applied very easy and don’t lay on very thick. And we’ll try to get you through to terminal bud set.
Now let’s say something awful happens and you do see fire blight. Try to pick a cool day. A day like today would be good, except there’s a lot of rain. You want cool, dry weather. Fortunately, we’re having a lot of cloudy, overcast weather that prevents us from seeing exciting things like eclipses and the northern lights. But at the same time it makes it fantastic when they’re dry for moving fire blight strikes. What you’ll want to do is you want to cut into last year’s season’s growth and about twelve inches into the healthy tissue of last seasons growth. So find out. You can see where the new shoot is growing, such in this case. And you want to move all the way back into the wood, as you can kind of see here, cutting all of that away and leaving a stub in last year’s wood. Fire blight has the hardest time moving from present year to second year wood. And if you can go into third year wood, that’s even better. And sadly, if you have a really young tree and you’re like oh, my second year wood is my scaffold, it might be time to remove and replant. Once this gets into the main leader or a heavy scaffold, then you might have a bigger problem with inoculum spreading around the rest of your planting. And it might be better to remove the tree.
You can do a rescue program if you want to go for it. Usually it’s about 6 to 12oz per hundred gallons of prohexadione calcium. Wait five days to let it act, you want it to get moving. You want the trees to use this PGR. And then you prune out every two weeks up through terminal bud set. You might want to do an additional application afterwards. And I think that’s going to get us into sort of the early post bloom set. We’ll probably do a pruning video, um, maybe a little bit later this summer we have another pruning trial and give us an opportunity to show you some pruning and the types of different pruning practices that we’ve been evaluating at Cornell AgriTech and my collaborators’ trials in Washington State and elsewhere.
State of the State with Dr. Anna Wallis
And now for the state of the state, your weekly roundup of phenology and degree day accumulations from the major fruit production regions of the state. I’m Anna Wallis with the New York State IPM program at Cornell, and the information I’ll be sharing has been aggregated from regional specialists, including Mike Basedow, Janet Van Zoeren, Mario Miranda Sazo, Craig Kahlke, and Dan Donahue. It also includes my own observations and information I’ve collected from NEWA.
In general across the state, this week we’re moving into bloom in some locations and into petal fall in other locations. So, we’ll be approaching thinning season in some of the warmer locations like the Hudson Valley, in western New York. And in other places, we’ll be getting into thinning season in the next week or two. As we’ve been reporting for the past couple of weeks, there is some evidence of frost damage in some locations so it’s important to be scouting your blocks and looking at different places in the canopy and across blocks so you can be tailoring your thinning accordingly. Thinning meetings are being held across the state, so pay attention to your region for those meetings. The Western New York and Capital Region thinning meeting was held virtually on Monday and the recording of that is available on the regional teams’ websites. In the Hudson Valley in person, thinning meetings are scheduled for this Wednesday, so hopefully you can attend that if it’s in your region. And the Champlain Valley thinning meeting is upcoming, so pay attention to announcements to attend that.
In many places there’s a large bloom and a lot of healthy looking fruitlets, so we are anticipating the potential for a relatively large crop. In the Hudson Valley, in Western New York, we had really excellent pollination weather and lots of activity of pollinators, so fruit pollination we think is excellent as well.
With regard to degree day accumulation, we continue to be close or ahead of 15- and 30-year averages. In the Hudson Valley we’re pretty close to averages, whereas in Western New York things continue to be a week or so ahead. We’re somewhere in between for Northeastern New York, just a little bit ahead of those 30- and 15- year averages. Last week, relatively cool temperatures kept things moving along slowly but steadily with relatively low insect activity. In most places in the state, highs were only in the fifties and sixties [°F], with the exception of the Hudson Valley where we had a couple of days in the eighties, the low eighties [°F], at the beginning of the week last week. We’ve had more rain, we’ve had a wet month of April, and so far it seems like a similar trend for May too. A warmer and wetter than average trend is predicted for the region over the next six to ten days, according to the NOAA Climate Prediction center, with most places in the state with forecasts in the seventies [°F], during the day.
Moving into phenology across the state now. In the Hudson Valley, degree day accumulation is just a little above the 15- and 30- year average. Apples are in various stages of bloom to petal fall. Honeycrisp fruitlets that were measured on Monday and Tuesday measured in the six to eight millimeter range. Pears are past petal fall and beginning to size. Stone fruit including peaches, cherries and plums are past shuck-split and beginning to size. We’re seeing our OFM flight peak, so keep an eye on that. Codling moth sustained trap capture was recorded this week with two weeks in a row of codling moth capture. Primary scab season is beginning to wane, although we’re still having a little bit of spore discharge and as far as fire blight, keep watching the models and any blossoms that are still open are still vulnerable, although by-and-large, the temperatures have been relatively cool aside from a couple of infection events that were predicted by the model last week. Plum curculio activity was found this week and last week. Despite the cool nights, we are seeing some both ovipositing and feeding activity on stone fruit and pome fruit.
In Western New York, in the Lake Ontario region and Geneva, the degree days accumulation continues to be well ahead of averages. Many varieties are moving into bloom and past bloom. Again, it’s important to be assessing blossom damage as we move into thinning season. OFM flight is peaking and codling moth trap captures were reported in a few places this week, including a sustained trap capture in Geneva.
In the Capital Region, we’re near average degree day accumulation, maybe a little bit above the averages this week. With predicted warmer temperatures, we’re moving into full bloom and then into petal fall beginning on Monday, depending on the variety. There’s a little bit of damage to kings that’s been noticed, but by and large a strong bloom and potentially good fruit set. There are rainy conditions in the Capital Region like in the rest of the state this week which may have some implication for pollination, although we’ve also had some great weather for pollination as well. We’re nearing the end of the primary scab season and again continue to watch those fire blight models as we have any blossoms open.
In the Champlain Valley, early varieties like Zestar are in full bloom now with other varieties beginning king bloom. We’re slightly ahead of degree day accumulations this week with a little bit of a warming trend. Again, rainy conditions are also expected this week, so we’ll be looking closely at pollination conditions. We’re in the middle of primary scab season with another scab event predicted this week with significant spore discharge and fire blight risk remains low with the cool temperatures, but keep an eye on those models.
And now for a few upcoming pest events. Again, our early season insects have been fairly quiet with the cool temperatures across most of the state with the exception of a few warmer 80 degree [°F] days in a couple of places. We’re moving into petal fall, so that’s a critical time to be looking for insects and managing them. We’re seeing a little bit more aphid activity, continuing to find green aphids and rosy apple aphids in clusters. So you can be looking for those in clusters or distorted leaves are also really indicative. We’re finding more woolly apple aphid across the state. This insect again overwinters typically on the roots and then emerges to the aerial parts of the canopy. We’re finding infestations, typically on old pruning cuts lower in the canopy that are easier to see if you’re crouched down and looking up into the canopy, so make sure you’re looking hard for those. We’re finding colonies of aphids covered with abundant wool, so they’re easy to find if you know what you’re looking for. Talking about the lepidopteran complex again, the OFM biofix was set in many places this week or last week, and we’re continuing to see flight. Codling moth sustained trap capture was reported in Highland, at the Hudson Valley lab, and in Geneva, and we’re seeing the first flight in many other places. Obliquebanded leafroller and other overwintering lepidopterans were found early this season in terminals and in clusters, and we’re continuing to see activity there. So, keep an eye out and be scouting your orchard. Make sure to put your traps out at petal fall if you’re going to be scouting for that insect.
In the Hudson Valley, we continue to see a lot of spongy moth activity, which was previously known as gypsy moth, and we’re seeing that move a little bit northward, so keep an eye out on that. European red mite can also be problematic at this time, so you can begin starting to scout for that insect. We haven’t heard any reports of problems for European red mite or other mites yet, possibly because of all the wet weather. Plum curculio is an insect that begins moving into orchards around this time. Typically when temperatures are above 60 degrees Fahrenheit, it begins to be active, especially when we have a few warmer nights. They’re not very mobile and they don’t usually fly, so they’re usually coming in from the hedgerow where they overwintered and you’ll find them on the edge of the orchard first, we’re beginning to see some feeding and oviposition on stone fruit and on apples now. The duration of their activity depends on temperature, so you can be using the NEWA model to predict if they’re still active in your location and for how long. Usually it takes two to three insecticide applications, but again, that’s dependent on the degree day accumulation, so you want to be keeping track of that.
With regard to diseases, we’re moving out of primary season in many locations in the state and in the middle of primary season in cooler places in the state, you can start to see the infections and the lesions about two weeks after the infection event occurred. We’re seeing very few lesions in many places in abandoned blocks where we know that haven’t been managed. So, keep an eye out for those. It could just be the cool weather is making it take a little bit longer for those symptoms to show up. Fire blight has been lower risk in many places due to the low temperatures that are keeping inoculum from building very quickly, with the exception of places that had higher temperatures in which bacterial colonies can grow really rapidly. So keep an eye on those newer models and the forecast that Kerik is reporting. We’ve been finding less powdery mildew. We were finding it earlier in opening buds with twisted and distorted tissue covered with powdery white sporulation. But with all of the rain, this pathogen can’t survive in standing water.
Thinking a little bit about cherries and berries we are starting to think about fruit flies in cherry and berry plantings. We have started thinking about putting our traps out for both European cherry fruit fly and spotted winged drosophila. And if you’re going to be monitoring for these insects, we encourage you to be starting to think about doing the same. It’s been a warm, wet spring and so we expect early emergence of these insects. We’ve updated the quick guide for insecticides for both of these insects and they’ll be available on the Cornell Fruit Resources page and they’ll also be distributed through the regional team newsletter so you can be paying attention for that.
As we’re moving into these critical management periods, I just wanted to give you a couple of reminders of updates that we’ve made to the NEWA apple models and other resources, and all of the links to these resources are in the show notes. The NEWA fire blight model has been updated to help you guide streptomycin applications. It’s been updated to visualize the effects of streptomycin application up to five days in the future, and so this can help you find the most optimum timing for reducing risk of fire blight in your orchard. The NEWA Help desk frequently-asked-questions and table of contents is a new feature on the NEWA Help desk page, and so you can navigate to NEWA help desk and find a list of frequently asked questions that links you to three to ten minute tutorials organized by crops. Also on that page is a NEWA quick guide for apple insect pests. And so in addition to those video tutorials, we created a NEWA quick guide with the purpose of providing a quick overview to those models. It includes an introduction, the definitions of some key terms used in understanding models, and model explanations for plum curculio, codling moth, oriental fruit moth, and oblique banded leaf roller.
And now here are the current degree day accumulations for major fruit producing regions of the state throughout the season. We’re aligning this information with previous work done by Art Agnello relating to McIntosh phonology and degree days. This information can also be found in table 7.1.4 in the Cornell guidelines. As a point of reference, pink for McIntosh is around 289, full bloom 378 and petal 479. In Geneva we’re currently around petal fall with 550; Highland at the Hudson Valley lab is at Petal fall with 615; Clifton park is at Bloom with 492; Peru is about pink with 384; Medina, an inland site, is at Bloom with 555; Appleton North, a lake site, is at Bloom with 467; Fairville, the apple shed, an inland site, is at Bloom with 504; and Williamson DeMarree, another lake site, is at Bloom with 500. That’s all for now, and good luck until next week.
| McIntosh Phenology and DDs (43F BE) (avg +/- std) | |
| Phenological Stage | DD Accumulation |
| Silver tip | 58-106 |
| Green tip | 99-144 |
| Half-Inch Green | 150-201 |
| Tight Cluster | 206-257 |
| Pink | 267-316 |
| Bloom | 344-415 |
| Petal Fall | 439-523 |
| Phenology & DDs for NY NEWA Stations from 1/1 – 5/14 | ||
| Station | DD Accumulation | Stage |
| Geneva | 550 | Petal Fall |
| Highland (HVRL) | 615 | Petal Fall |
| Clifton Park | 492 | Bloom |
| Peru (Forrence) | 384 | Pink |
| Medina – Inland | 555 | Bloom |
| Appleton North – Lakeside | 467 | Bloom |
| Fairville (The Apple Shed) – Inland | 504 | Bloom |
| Williamson (DeMarree) – Lakeside | 500 | Bloom |