Season 7, Episode 2 - End of Winter Wins

Don, Kari, Greg, and Shan dig into stone fruit losses and disease timing as a warm spell pushes early peaches toward bud swell. We outline what early scouting actually tells you and how to get ready for oriental fruit moth and codling moth.

If this helped sharpen your spring plan, follow the show, share it with a grower who needs timely cues, and leave a quick review so more orchards can find us.

Soil Fumigation: https://extension.psu.edu/fumigation-and-other-strategies-to-control-soil-pests

Heat School: https://sparcscri.com/event/wsu-tree-fruit-heat-school/

Photo Credit: Don Seifrit, Penn State

Music Credit: “The Raven and the Swan” by Josh Woodward is licensed under a Attribution 3.0 United States License. Courtesy of FreeMusicArchive.org

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Flight Seasonalities of Main Fruit Pests During the Growing Season

Transcript

SPEAKER_03 0:07

All right, welcome back once again, everybody. I'm Don Seafer. It's the Dr. Tree Fruit and Dawn Podcast. It is Tuesday, March 3rd, 2026. Uh it feels like it shouldn't be 2026, and it certainly shouldn't be March, but here we are. I'm here with Dr. Carrie Peter. Say hi, Carrie.

SPEAKER_00 0:23

Hi there.

SPEAKER_03 0:24

Uh Dr. Greg Krawchek, say hi, Greg. Hello, everyone. And our our lead-in for this episode, uh, Dr. Sean Kumar. Say hi, Sean. Hello, everyone. And Sean, uh, we will let you go first and and give a brief update on some of the things you've been seeing.

Winter Hardiness And Bud Damage

Stone Fruit Losses By Site

Bud Sampling And Thinning Plans

Apple Damage And Spring Timing

SPEAKER_04 0:39

Sure. Uh thanks, Don. And so, as uh uh many of us experienced, we've had one of our uh really good winters uh, so to speak, this year, as compared to what we've had very mild winters in the past two years. So, one of the consequences of that is hopefully our root stocks, which have which we have seen through research done at Cornell, that some of these root stocks that are very coal susceptible, they've gained enough hardiness so that they're able to withstand some of this uh seesawing weather that we sometimes get in March. Uh and so they're able to be a little bit more coal tolerant uh coming out of hardiness as the temperature increases, uh, because they're able to they were able to accumulate a lot more hardiness uh than say in a mild winter. So I think that's good. I think that this long winters uh and cold winters are good in that perspective. The other thing I wanted to mention was uh our orchard Rock Springs is in a very, very cold site, and so we had uh some very cold nights uh into minus 5, minus 10 Fahrenheit, uh, or sometimes even lower uh during January, and so we wanted to check on how our stone fruit are doing, and uh so we checked both our peaches, which is Red Haven, and Nectarines Avalon. Uh uh because of the fact that we are in such a cold site, I think, and the fact that cold air settles uh uh uh in that area, we lost uh all of our nectarines and about 93% of our peaches. Uh however, having checked another orchard that's just a few miles down the road, uh, we saw that they only had 40% uh damage to the Red Haven, same variety. So it really depends on your location again. I think anywhere from 30 to 50 percent is actually not bad because it helps with thinning and and then hopefully you don't have a severe frost and takes everything else out. But uh around 30 to 50 percent damage is what we would normally sometimes see because of these cold weather in events for peaches and nectarines, but it really depends on your location again for elevation and exposure to the cold winds. But that is just a uh fact uh statistic I just wanted to put out. Uh so if you're interested to know how your peaches did, how your peaches survived, especially if you're in the central northern parts of the state, uh then it might be good to basically harvest some stems, keep it in room temperature for 24 hours, and then cut open the stems, uh cut open the buds and check for uh browning of the style or ovule, and then you'll know whether your bud is uh dead or alive. And usually I take about hundred uh buds spread out around the orchard and then do a ratio to find out how many buds are alive. And or some people like to do just wait for uh when we get closer to bloom to see see how how uh how bloom is, and you can you can judge based on that. But for those thinking about blossom thinning of peaches, uh I think that it'll be good to do it a little bit earlier, so especially now that you have a little bit more time to make sure that you have an idea of what the status is of some of your peach varieties, so you can then plan for blossom thinning of your peaches uh when when you have bloom. And so uh with apples we saw some damage, around 10 to 20% uh damage, but nothing nothing very nothing very major, and only in very, very cold sites. So I think that uh so far I think we are uh the buds seem good and we seem uh like hopefully have a good season. And I don't have anything else to say, I think. Yeah, and I think we're still a bit away, uh still a few weeks away, I think, from any sort of uh like fertilization and uh other sorts of spring uh spring activities as far as horticulture is concerned.

SPEAKER_03 4:49

Sounds good. Uh do you want to give uh a brief kind of just uh here's things that are on the docket uh coming up for uh later? Yeah.

Disease Outlook And Warm Spell

SPEAKER_04 5:01

Yeah, uh so uh so folks, I did want to mention uh that we have a virtual fruit school uh uh which is basically uh about heat issues. We've noticing that more and more we are seeing sun damage, uh sunburn damage, especially we used to see a lot of it in Premier Honey Crisp and Honey Crisp, but we are noticing a lot of it sometimes in even later varieties like uh Evercrisp and Pink Lady. And so this fruit school is dedicated to learning more about how heat affects uh the fruit and how sunburn progresses, and how what are some of the ways in which we can minimize uh sunburn. And so this fruit school is being run uh out of Washington State, uh, and it's on the 11th of uh March. And uh so what they're doing is we are hosting a virtual uh school that coincides with their timing. So it starts at 11:30 a.m. to uh 6 p.m. at FREC, and then the Freck Auditorium. Uh we are going to zoom the their talks, their live talks right in the auditorium. So and then uh please register for that by uh by the 6th, by this Friday. And Don is going to I think attach the link to that registration and then you can get more or learn more information about uh sunburn and what are some ways in which we can mitigate it and how that affects fruit color and things like that. And uh so yeah, so the there's an option to register virtually fully, like you could register virtually, but you can also register to be part of that in-person uh fruit school that we are hosting at Freck uh on March 11th again from 11:30 a.m. to 6 p.m. And so more information will be provided in the link to this podcast. But uh I encourage you to register and be part of this free fruit school.

SPEAKER_02 6:58

Yeah. Awesome. Thanks, Sean. And Dr. Peter.

Peach Leaf Curl Spray Window

Dormant Copper For Apples And Pears

Fumigation Workshop Details

SPEAKER_00 7:04

Okay, so um as we speak, there is uh the first disease update of the season is being processed, and hopefully it will be sent out um some by Thursday of this week. So uh what has triggered this update is the stretch of warm weather that's in the forecast beginning later this week. Um, we see some upper 60s, upper 70s, mid-70s, low 70s. Um, but most importantly, it's the lows are in the 50s, so it's actually going to be a very mild, mild evenings overnight. And so with that said, I just wanted to remind people that if you hadn't had hadn't had a chance to do so to sort of implement your mitigation measures to decrease that pathogen load in the orchard. Um, so a few things to be thinking about. First, I want you to be thinking about your stone fruit, mainly your early season peaches and nectarines that may be afflicted with peach leaf curl, because we are in the home stretch here before bud swell, and peach leaf curl sprays occur when there's no leaves on the trees, because that's when the um basically the spores are exposed because they live in the bud scales. And so this is when the spores are exposed and when the fungicides will work. Once the leaves come out there, and once you have bud swell, then the spores become protected. So this warm-up, I suspect, is gonna kind of really move some of these early peach varieties along. So this is just a gentle reminder if you hadn't gotten on your peach leaf curl spray to make sure you do it ASAP. Um, the fungicides that you want to be thinking of are copper, xyram, lime sulfur, chlorothalonyl, um, and really any fungicide is gonna work. I tested even um lunacensation last year um just to see, and it worked too. So um, but you can be conservative. Copper, xyram, lime sulfur, chlorothalanyl. Uh, and also as you are um probably will be getting if you haven't already started your pruning for your stone fruit. There's any mummies in those trees, make sure you knock them off because they can become little spore factories. Um, so just be sure to do that. Because again, we want to decrease the pathogen load coming into the 2026 season. We have a tough time eliminating it completely, but we can at least reduce the spore load out there. For apples and pears, I would say you can probably wait a few weeks because we still are are kind of have seesaw temperatures coming up. But don't forget, um, if again, if you didn't do this in the fall, sort of that dormant copper spray to put on your apples and pears. You want to aim for two pounds of metallic copper per acre for the whatever copper you use. Look at what the metallic copper content is on the label. It will tell you how much metallic copper per unit of product is in that product. Uh, and so we want this will help with knocking back scab spores, maybe even bitter rot spores, fire blight. Uh, and so this is you know a good sanitation cleanup as far as having reducing that bacterial and um spore load, um fungal spore load. In the case of fire blight, what you're doing is when you kind of cover your trees in copper, when those cankers wake up, it'll once they start oozing, they'll meet that copper and that's on the on the tree, and it should knock back the bacterial load that's coming from those overwintering cankers. Uh, and so this will cover uh a lot of different um diseases and pathogens. Uh, so again, if you didn't do it in the fall, you still have some time. But I would say the priority right now is the peach leaf curl spray if you haven't done it yet, because the trees are going to be moving with this brief warm-up. But looking at the long-range forecast, we're gonna dip back down again. As we were chatting right before we started this, March is the schizophrenic month because it doesn't know what it wants to be. It still wants to hold on to winter, but it's warming up with spring, so it is all over the place. And so let's um so just just you know, be mindful of these warm temperatures coming up. Uh, and um, the last thing I just want to put a shout out for as far as announcement goes from the plant pathology side of things. Uh, Daniel Weber and I are going to be hosting a fumigation, one-hour fumigation workshop in two weeks on March Thursday, March 19th at 1 p.m. at FREC. You can also do it online. Um, there also will be an opportunity to join join online if you are not living near within the driving distance of FREC. So this will be two fumigation credits. So I know that for a lot of people, the March 31st is the deadline for credit renewal, and people are in need of those two fumigation credits. So this will be a one-hour you'll get to listen to me talk about fumigation do's and don'ts and and what all needs to be done. Hopefully, I don't put you to sleep. Um, but yes, so and no, there is a fee of$10 for this. Um, and so this is just per the the policy of uh for extension meetings now. Uh and so uh be there should be some information that'll be coming out. Um unfortunately, I would tell Don to put a link in the as far as in the summary section for this, but maybe just put a reminder um as far as to check the workshop site on the Penn State Fruit Extension. But hopefully an email should be going out soon with it. But it's March 19th at 1 p.m. at Freck. It will be in person, but it'll also be on Zoom as well.

SPEAKER_03 12:54

Very good. That's all good outline of things. So um, and last but not least, Dr. Greg, Dr. Krawchack.

Early Pest Activity And Monitoring

Traps, Lures, And Timing

Dormant Oil Use And Cautions

Managing Pear Psylla Strategy

New Insecticide Zivalgo Overview

Mandatory EPA Mitigation Requirements

Readiness, Labels, And Next Steps

SPEAKER_01 13:05

Thank you, Don. Hello everyone again. I will not be talking about spray. Or maybe, maybe something. Um Kerry already mentioned this. Uh March is kind of a month that can't decide which way to go. The problem with this is that some insect pests which overwinter as adults when we will go into those next five days with forecast at temperature above 70, they may become active actually. They may become active and they might start doing something. The one that you really should think about is pearsilla. They overwinter as adults in or very close to the pearl orchards. And any day with the sunny weather, temperature above 60, they might they might start flying, they might start mating, and they will start laying eggs. Will those eggs survive? Will those eggs mean anything? Well, it's uh anyone's call. Probably not. I mean, we still have a long time to go before they will really have anything to feed on and so on. They won't be green tissue too soon. However, if we go extended periods with the warm weather, and you have a pear orchard, after that period, you can go to the orchard, look at the growing shoots, and look for those tiny yellow oval specks. They are tiny, I don't know, one tenth of an inch, maybe even smaller, but you can actually see them, and you know this might be a good indicator what you're gonna see later on. So you don't have to control them because the chance for them to survive is very, very small, almost non-existing. However, it might be a good indicator about potential pressure because those adults will come out, then they will survive another cold span, and then they will be out again. So this is something to you know think about. If you don't wanna look for them, well there is nothing else you can do other than hey, let it go. However, March is also the time for preparation for the regular season. Uh I just played place my order for traps and lures for monitoring almost all the insects that I'm planning to monitor this coming season. What did we buy for this season? Well, I bought a lot of things that you don't need, but Oriental fruit moth, codling moth, brown marmorated stingbag. Uh those of you that worry about uh small fruit and spatted winged rhosophila, you can buy traps for the spatted winged rhosophila, oblique bandit cliff roller, all those lures, it's a good time to get ready. Also, check your traps, are they still holding on, or you might need to replace some? This is the time to do it. When they need to be out. Well, it varies of course from the season. Uh taking into account what happened in the last two years, we got first oriental fruit moth flying basically in the first week of April. We got our codling moth flying last week of April, first week of May. This is basically codling moth usually starts around the pink just before the pink on apples. Saying this, truth and insects have a different heat sensitivity. And tris when they start, and Sean can correct me, when they start, they just keep going. With the insects, when the temperature gets lower, they will slow down and they will just sit there and wait until the temperature will be right. So truth might be ahead of insects in development. Using phonological times, you know, usually we can say that OFM is flying when peaches are ready to bloom, codling moths are ready to fly when apples are ready to bloom. However, this might not always be the case. But saying this, you put the trap out, and then you have to worry about it because when they start flying, you will see them in the trap. So this is something to really think about. Um insecticides, and I keep saying this for the last at least five years, do we need to use insecticides before they bloom on apples? My personal opinion is that no, we don't. However, it might make sense to use if we know what problem we're trying to address. If we see now is the pruning time, and I know after the very cold time, now you guys probably in a rush to finish the winter pruning. If you see European red mite eggs and they are easy to spot, basically the branches are getting ready. And when you touch the branch with your fingers, your hand will be red too. If you see European red mite eggs, if you see scales, and they are also easy to spot, they are not red, but they are easy to spot, then maybe you should consider using oil, dormant oil. One thing with the oil is that you really should not use it when there is even a chance of the temperature dropping below freeze level, below 32, within number of and then I don't know, two to seven days after the spray of oil. And this is something to remember because you don't wanna burn the developing buds, flower buds, and so on, with the oil. So this is something that you can do. If you know that you're gonna use oil, the earlier you use, the higher concentration will work. I don't think going anywhere higher than 3% makes any sense, but the closer you go to the actual green tissue being present, the concentration should be lower, going even into 0.75, maximum one percent. Oil also will work for fersilla X, but again, the temperature is a factor here. Doing oil in probably in April, I don't expect really March being the time, however, I don't know the weather, I don't know the forecast. It's possible that going maybe two times with oil on pearls and then finishing it with oil plus pyretroid will help you to kind of synchronize the development of Persilla. If we don't do the oil, there is a pretty good chance when we get into the petal fall on Perth, and that's when you go with the agrimec. You know, it's not a great thing, but it still works some places. If you go with those kind of applications, you will be trying to kill basically all instars of Persilla if you don't do the oil and pyretroid before this white bath stage. But if you do, the chance is that you will kind of synchronize the population and Then you will be dealing either with nymphs or adults, not all of them at the same time. So again, it's a I said I'm not gonna talk about sprayers sprays, but again, oil is oil. I mean, it might or may not be in your arsenal. Um what I want to mention, and this is kind of difficult, and I think we will cover this in details when we start our twilight meetings in April, May. There is a new insecticide on the market, Zivalgo. Z-I-V-A-L-G-O. It's an insecticide with a completely new mode of action. It's being sold, marketed as a product that works on everything. It works on codling moth, leaf rollers, persilla. It even has mites on the label. It is a good product. We tested it and this is my program. We work with it on peaches, and it was very effective to control plum curculio, effective in controlling oriental fruit moth, stinkbox. We never look for this as a acaricite. It was also very effective in controlling persilla. So I don't want to use it, but the way how I think about it is almost as broad spectrum as the old Gutayan used to be. It's not a Gutayan, it's a different mode of action. There is no other product on the market with the mode of action than Zivalgo has. However, it's a very broad spectrum product. So that's the good part about it. What is uh kind of frustrating, and I afraid all of you will find it very frustrating, is when you start going through the label and realize that in order to use this product, you have to go to the EPA website, change, check the mitigation program, and then follow it up because there is a mandatory runoff mitigation program when you use the Valgo. Just for the sake of it, I try to go it go there today, and you have to go to multiple websites at within EPA, you have to print multiple documents, and you have to have them in the possession if you're gonna use this product, and if you're being checked, you have to prove that you had it. And there is also a thing, you have to generate so many points, your or chart, your application has to generate so many points in order to be able to use this product. I mean, it's it's a pain, and again, it's March, there will be colder days, and you looking for something to you know entertain you in a very negative way. Just find the label. It is a viable, you know, for this is a product from Singenta. Find the label and start reading it so you are ready to use this product. When you go through it, you have those documents, then you can use it. You have three applications per season, maximum rate is 2.5 ounces per hundred gallons. It's a very effective product, but you have to be prepared to use it. If you are not prepared, well, since label is the law, you basically cannot use the product. And I I really wanna see people who are not very keen about using the internet and going on the website and printing and stuff like this, how are they gonna use this product? This product was used as the poster child example, how old new registrations will look like. And that's why it's supposed to be registered more than two years ago, but it's not registered, but now it has the registration. Again, I will say it probably third time, it is a very good product, very effective product. However, you have to be prepared to use it, and we're gonna talk more about it during our twilight meetings, which I hope we can figure out the dates for and announce them pretty soon, the dates and location, because we don't think about it, but it's six weeks, if I if I am correct. So that's all I have at this moment. I mean, please don't ask me about all those details with the Zivalgo, because I can go into it, but it's not fun, it's really not fun, even if you are really familiar with the computers, with the website, with the downloading, checking, and stuff like this. It's not fun. But if you do it once, and chance is this whole new process was established to fulfill requirements of the Endangered Species Act, which basically is to protect endangered species of animals or of plants from the impact of pesticides. So get the label, start reading it, and get ready. So that's all I have, unless there are any questions from Dan or anybody else on the call.

SPEAKER_03 28:35

Thanks everybody for jumping on here. This is a pretty quick one, which is pretty good for us. Uh, but it is the start of the season. These will get much, much longer as we progress, I'm sure. Um, thank you everybody for jumping on here today.

SPEAKER_00 28:46

Yeah, and just as a note, so when the next one will be, because we aren't getting quite in the weekly yet, but I'd say once we hit bud break, that's probably when it'll be go time. So definitely.

SPEAKER_03 28:58

So all right, say goodbye, everybody.

SPEAKER_00 29:01

See you later.

SPEAKER_03 29:02

Bye. Thank you.