2024 Scaffolds Digest: Week 14
This post is a text digest of the Scaffolds Podcast. To listen to the original episode, visit the following link: Scaffolds Podcast on Spotify
On this week’s episode of Scaffolds, I speak with Dr. Awais Khan, an associate professor and geneticist at Cornell AgriTech, about his sabbatical trip to the point of origin of Apple. Kerik talks about Captan being under review by EPA and other topics, and Anna gives us our state of the state update on degree days and trap captures.
Monique Interviews Dr. Awais Khan
Today, I have the pleasure of speaking with Dr. Awais Khan. He’s an associate professor in the School of Integrative Plant Science in the Plant Pathology and Plant Microbiology section, and is based here with me at Cornell Agritech. Hello, Awais.
Awais: Hi, Monique. Thank you for having me with you today.
Monique: So I really wanted to talk to you about your sabbatical trip, where you ventured to the spot of origin for apples. Can you tell us a little bit about where you ended up?
Awais: Yeah, this actually, this is a lifetime kind of adventure idea. I’m really excited about this, that I have actually done this trip. So basically, I went to this trip in August last year, and I came back from this trip in January last this year.
Monique: So you went to which countries?
Awais: So the trip started from New York. I went to Turkey, and my main destination was Turkey. And in Turkey, I was basically, many people are familiar with big cities like Istanbul and Ankara and Talia. So I was kind of in the middle of Turkey, close to, close to Adana, maybe some people know Adana kebabs. And so I was in a city called Adana, and that was the main destination. But other than Turkey, I have visited Kyrgyzstan, Kazakhstan, Pakistan, as well as I went to Georgia and a little bit of Greece as well as Pakistan. So in total, seven, eight countries I have traveled in this trip.
Monique: Were you looking at apple production or were you going to wild areas with wild apples?
Awais: So I think overall, the excitement for me for this trip was looking at apple genetic diversity and then apple production. But also, very importantly, I like cultural and also cuisine from this region, and I was really excited to try these different cuisines and also look at the history and culture in these countries. And also at the same time, I have established a lot of networks and connections in this area because, again, as I said, I’m excited to work on genetic diversity of apples. And this region is the origin of domesticated apple.
Monique: So did you get to go into any of the fruit forests?
Awais: Yes. So I think, as you, you might remember, I called this trip as my sabbatical along Silk road, following the domestication path of apples. So I have gone to, so maybe before I get into my trip, I want to just introduce a little story about apples. So how we got apples in North America, this is really exciting, and I’m always amazed by the story, how we got apples in North America. And I will also tell you that now it’s almost 20 years, I started in 2004 working in apples, and it’s about 20 years for me to work on apples. So I think the most compelling thing for me and most motivating thing for me is looking at story of apples. So, domesticated apples, they started from central Asia in Tianshan mountains, and these mountains are between China, Kazakhstan, and Kyrgyzstan. That region and the main progenitor species of domesticated apple called Malus sieversii, that is from, is native to that region, Kazakhstan, Kyrgyzstan, China, Tianshan mountains. And so Silk Road, which was a connection between eastern and west, it goes through these countries, and in old times, there was a trade between east and west through this silk road, and it was also connecting Iran, Turkey, south Asian countries, and they’re coming to Europe. And there are also many other wild species in addition to the species which is native to Tianshan Mountains, Kazakhstan, Kyrgyzstan and China border. So in Turkey, there is another species called Malus orientalis. And then if you go to Iran and Armenia and Georgia, you can also find wild Malus orientalis in this region. And if you go on the other side of Tianshan mountains, you can see Malus baccata in China. And then these traders were moving wild apples from central Asian forests, Malus sieversii, from Kazakhstan, Kyrgyzstan, that region to east. This other apple, called Malus orientalis, was also hybridizing with this native central Asian species, Malus sieversii. And if that Malus sieversii was taken on the other side of the Tianshan mountains, where Malus baccata was, it was also hybridizing with Malus baccata. So in that way, which started its journey from central Asian mountains, in east, it hybridized with Malus baccata, in west, it hybridized with Malus orientalis. So in Turkey and Georgia, Armenia, I was interested to see Malus orientalis, which also has significant contribution to domesticated apple. But then if I extend the story of apples from Turkey, it also entered into Europe, and in European countries, especially north northern European countries, there is also Malus sylvestris, which is native to this area and it also hybridized with the apple, which was traveling from central Asia to Turkey, Armenia, Georgia, hybridizing with Malus orientalis. And now it was hybridizing with Malus sylvestris in Europe. And then also people were selecting good tasting apples. And then in 1600s, the Europeans came to North America, brought that apple, which originated in this way to North America. So there was no apple in North America before 1600s, and this domesticated apple landed in this, this area. And before you ask me the next question, I would say why I’m interested, as a geneticist, as a pathologist, to go look at the diversity of apples in those regions. So, in plant pathology, we say coevolution, host and pathogens, they coevolve over time for centuries. And apples, domesticated apples, which are grown in North America, they didn’t have really long time to coevolve with native pathogens from North America, because they were introduced here in 1600s, and then they were clonally propagated or managed. So if you think about coevolution, coevolution happened with apples. And the pathogens in central Asia are in other parts of the world where apples coevolved for centuries with those pathogens and pests. So my interest to go in those countries is also to look at the resistance to these pathogens existing in those wild apples. And that is one of the interests I had.
Monique: In the different species that you encountered or in the wild apples, did you find anything that surprised you?
Awais: So when we think about wild, we think really wild species growing everywhere. And for apples, that’s not the case. And especially now, when we have so much of urbanization, so much of population increase, and cities are growing like crazy. So you can still find genetic diversity and wild apples in the mountains in very small batches. It’s not like you can find them everywhere, or you have to hike a lot to really get to those wild, wild apples. And another thing is apples, wild apples, you, if you grow any apple from seeds, if it’s not a cultivated variety, you might see it as a wild apple. So it is also not easy to recognize. This is wild, and this is, this is Malus sieversii, or this is Malus orientalis. So some experts or some local hosts should be there to tell you that what you are looking at. And for example, in my lab, we do genetic analysis to confirm this is Malus orientalis, this is Malus sylvestris, this is Malus sieversii. But in wild, when you see them, it’s not easy to recognize them. And also they are not easy accessible, and they are not in abundance. So I have many colleagues in these countries, and they were able to take me to different regions where we can find Malus orientalus in the Black Sea region of Turkey, or Malus sieversii, she is the main progenitor from central Asia. So I went to Kyrgyzstan around this lake called Lake Issyk Kul. And I have seen some wild Malus sieversii in that area. Then again, I went to Kazakhstan, which is on the other side of Lake Issyk Kul and Almaty, father of apple, one of the biggest cities in Kazakhstan. And close to that I also have seen some Malus sieversii. But it was a lot of hiking to find them, and unless I had this local host, I was not able to recognize which are Malus sieversii.
Monique: Is that a testament to how similarly it looked?
Awais: Uh, yes, you’re absolutely right. Malus sieversii, they look very similar to domesticated apples. You can also see them having not very big fruit, but medium sized apples. You will see them, I mean, a lot of horticultural traits and a lot of fruit size, fruit color, these traits, you can see it in Malus sieversii that they are very similar to domesticated apples.
Monique: When you were interacting with people in these different regions. What was their relationship to apples and how do you think it differs from people in the US?
Awais: Oh, that’s, I think that’s a very big difference. I see in terms of connection of people with apples in those countries and here, economically it’s very important here, but I think culturally and historically you can really see that people in central Asia, in Turkey, they have strong connection with apples. So for example, if you go to city center, you will see a lot of art related to guessing apples, names of cities based on apples. In Turkey, there is one apple called Amasya apple, and Amasya is a city close to the shores of Black Sea, so Amasia is the town, so I went to the town of Amasya, very beautiful street, but this Amasya apples are very, very connected. And Turkish people are really proud of Amasya apples. They are small, medium sized apples, very nice, crispy apples. They’re not in very big commercial production at the moment. Historically they were very important. But people really, if you talk to a lot of Turkish people about apples, they instantly think about Amasya, the similar way you go to Almaty father of apples, Almaty means father, the name of city is father of apples. And if you go to Almaty, in every corner you will see something related to apples. You will see art exhibited everywhere in the city showing apples. There was an art exhibit, I participated in that art exhibit and they were showing Aport apples. Apples are also very famous. And actually Almaty has a very strong relationship with Aport apples. But Aport apples came from thing from Russia. There’s no really confirmation, but most probably they are coming from Russia. In 1800s, they were brought to Almaty, to Altai mountains, and it found a new home, and this was really a good environment for this apple. And they grow in a very big size, I think I have seen Aport apples from 200 to 250 grams and sometimes close to 800 grams per apple. And again, they are not in big production, in commercial production, I think they are about 5% of apple production in Almaty region. Again, when you talk to somebody in Almaty about apples in Kazakhstan, they will think about Aport apples.
Monique: It sounds like there’s different regional apples that are more wild type that are favored by these communities. So how does that translate into the cuisine? Do you also see a lot of apples in the cuisine? Or, you know, ciders? Are there any products from these specific apples that are not just the apple themselves?
Awais: Fresh eating apples, that’s one major thing, but also cider and also in pies and some cooking apples, that’s also a culture. Some, I think I heard that people also try apples and consume them when they were not freshly available. So I think a lot of apple related cuisines and so some products. Another thing I might forget that in Almaty, when we were there, we didn’t really plan about that specific event, but there was an apple festival on, I think, 15th or 16th September, and our trip coincided with that. And every city, every part of city was really lit with some activities related to apples were going on in the city. A lot of music, a lot of festivity around apples.
Monique: Wow, that’s so cool. Were you able to go to the Tianshan mountains? Did you go up in those fruit forests?
Awais: Oh, yeah, I was going to forget about this. This is actually my lifetime memory. I will always remember that. So I wanted to go in Tianshan mountains, see apples, this main, progenitor of apples in the mountains. And my host, who is professor in National University in Kyrgyzstan, she told me, it’s pretty far, it’s not that easy to get there. And I said, I made this big trip, I want to go and see apples in the wild. And then she was able to connect me with some foresters, local foresters in that area. And that forester was working there, I think he might be close to retirement, but he has been working there for a long time, so he knew every mountain and place where you can find apples. And I said, yeah, that’s exciting. And they asked me a couple of times, do you want to actually go there? And I said, yeah, I want to go there, I am very serious, I want to go there. So they pulled out an old Russian Jeep, which was full with grass, and I think nobody was really driving it around, but they were able to start it and we got in this car. I am originally from Pakistan, Kashmir, in northern areas, very rough roads, but I have never seen a rough road like that in Kyrgyzstan where we were driving this Russian military jeep, so we were there, it was unbroken. I was pretty, pretty confident we will make it to the next stop. So we drove maybe about 1 hour and then we have to walk, because that guy told us, the forester told us that there are some wild apples on the top of that mountain. And that mountain was very steep up and also there was a river going on one side. So I decided, okay, I came here, I will go there and see wild apples. So we did another like maybe 2 hours hike. And I am really impressed by the guy. He was really, you can imagine he was in maybe late fifties or close to sixties, but he was very good hiker, and I had to really catch up with him. And we were going up in the mountain, we went close to 2500 meters above sea level. And then we have to come down because those trees were really close to the river and there was no way to go directly to them. So then we had to come back down to the river and finally we saw Malus sieversii. Basically he told me that these are Malus sieversii, I could see some fruit on them and they were not managed, but I could see that apple scab is everywhere in Kyrgyzstan. But I saw them pretty clean. There was no disease on them, there was no insect damage on those fruits and I could see the fruit. I took some pictures with them and then we had to fight back. But it was like a trophy. When I saw those apples. And I mean, I cannot genetically confirm that they were Malus sieversii, but that guy knew that there are these 10, 15 trees of Malus sieversii in that area of the mountain. And yeah, we saw them, but the fruit was nice, and I posted many of these pictures on Twitter and LinkedIn.
Monique: I guess my last question for you is in this fruit forest, I guess what I know about the fruit forest is it’s not just apples, there’s also many other types of fruit, including nuts. Were you, did you see that like this mix of different fruits or was it predominantly like a stand of Seversii and then other trees that you wouldn’t know how to identify?
Awais: So you’re right, so it’s not like only one kind of tree is there. Imagine it’s a wild forest, that there are many other trees growing in there. So we, I have seen walnuts around that area, also I have seen conifers around, so there are many, many tall trees. So there are many small and also big trees around there, so it was not like just wild apples, so there are many other things in there. But one thing I might forget to mention, there is also significant threat to this genetic diversity of wild apples in this area. And that, as I mentioned previously, these are highly valuable resource for everyone globally, for sustainable apple production for our next generations and for centuries, for disease resistance, for insect resistance, for horticulture traits, for adaptation to climate and so on. But they are under threat from many, many things. So, for example, I said population increase, urbanization, because the people who live close to this area, where these trees are, they need wood for food, they need wood for constructing houses. They also need grass and other things for their animals. So that is one direct threat, those people could cut these trees for burning wood and so on. But in addition to that, there are new diseases. For example, fire blight was not a threat to wild apples in central Asia. But now we can also see fire blight in central Asia, in Turkey, in these countries. And these diseases, which might not have originated in this area, could be a significant threat to this trees. And then another threat is domesticated apples, apple cultivars. So apple cultivars, we also started to see high density commercial apples in this region. For example, you see Gala apples, you see Golden Delicious, Red Delicious, many, many apples in this area. And if these apples are growing close to wild apples, they can hybridize with them. And if they hybridize with them, the seed for the next apples in those forests will be hybrid, so will not be pure Malus sieversii or these other wild species. So there are multiple threats to these wild apples and diversity of apples. So I think there is need for new thinking to do conservation efforts, because in the past, there are some conservation efforts, but I think maybe those are not very effective. And I think we have to rethink, relook at them. How many are pure and how many are hybrids and how many, how much we have lost already?
Monique: Were you able to collect and bring back any genetic material or did you not have permits for that?
Awais: So it’s not easy to bring material back these days. And I think one of my objectives was one thing I wanted to see that diversity and see how it looks like and what are the issues there. But at the same time to make networking and have the collaborations. So I was very fortunate to have set up several collaborations in these countries. So I have listed more than 13 universities and institutions in these countries, so I have set the collaboration in Almaty with a national university, where there are two graduate students working on fire blight of Malus sieversii in the national park where we have this wild Malus sieversii. So I’m tired of bringing material back, I’m thinking to help my collaborators in Central Asia, Turkey and this region Kyrgyzstan to help them establish capacity to do research in there. So that’s, and we collaborate, we also have a genetic diversity of the species in here in Geneva, for example, National Apple Plant repository at USDA AgriTech and we can compare results, we can share results and we can train students across.
Monique: That’s awesome. This trip sounds like it absolutely was a trip of a lifetime and I’m super glad that you’re willing to share with us today.
Awais: Yeah, I’m really happy that you asked me about this trip and I will be excited to talk to you about it and other people whenever there’s chance.
Pathology Updates with Kerik Cox
All right, it’s another stormy weekend night. Lots of heavy thunderstorms, lots of heavy rain coming in, downpours in the middle of the apple growing season. What a great time for another episode of Scaffolds with an apple pathology focus.
There are some new concerns on the horizon. Captan again is under review by the EPA. There is a Captan amended proposal interim registration review decision that has some aspects that might affect our apple and stone fruit industries. Shout out to the New York Apple growers and thanking them for all of their alternatives to Captan research that they’ve been funding with our program. It is excellent that they have such foresight to see that these things could come up and may impact our industry.
All right, so if you want to check it out, you’ll want to go to regulations.gov, www.regulations.gov. And when you get there, you’re going to see a big blanket that’s going to allow you to enter the docket number, which is EPA-HQ-OPP-2013-0296. When you hit that, you’ll hit search and you’ll start to see things coming up. The public comment period is through July 31.
So if you were to go to the site and take a look, you’ll see it, you’ll simply paste in that docket number, and the things that will come up are some documents that describe the Captan amended proposed interim registration review decision case number 0120, and also something about the Captan public comment extension period. If you really want to get in there and make a comment, I like to typically click on the dockets tab over. You’ll see another non rulemaking result called Captan Registration Review Round One. Take a look at it. Once you’re here, you can click on the comments to the docket, you can see those, or you can tab back over in the middle and then you can see some of the docket documents. But if you click a second time back on the docket details back on the documents, you’ll finally get to a part where you can actually make a comment. “Pesticide registration reviews proposed decisions for several pesticides,” you’ll notice in this one that the EPA docket number matches the one that I provided earlier, EPA-HQ-OPP-2013-0296-0335 and you just hit the comment button and then you can add to the already growing number of comments on the docket list. It’s already up to 249. You can post them anonymously. You can post them as a grower, you can post them as a extension educator, regulator or researcher. You’ll see all sorts of comments on this. It closes again on July 31.
So with that, what is it going to mean? Well, we’ve seen this, and so what might end up happening in this particular instance is that apples, peaches, and nectarines could have a maximum rate reduced from four pounds of AI per acre to three pounds of AI per acre. Cherries not going to be too much, 3.16 to three pounds AI. If there is no reduction in the rate, there will be a six-day REI hand thinning for apples, peaches and nectarines, or a simply 24 hours hand rating for cherries. Now it’s not going to necessarily affect the apple industry there, but the six-day REI for hand thinning or, I would assume it also would be required for other hand activities in there as well, could be a little bit annoying. And of course the rate and reduction would mean less Captan use. So that’s it for Captan, make a comment if you like.
What else is happening? I wanted to go through and start getting back on our summer disease management tour. This is where we are now. We’ve passed the early stages of way past green tip, half inch green tight cluster, pink bloom, well past pink, and we’re in past the second cover as well. And we’re in the part of the season where we can still get pinpoint apple scab from late season infections. If there’s just a few hanging out in the orchard to moving into concerns such as apple blotch, Marsonnina, Glomerella, other things like bitter rot and the fly speck/sooty blotch. And I think in the key to sort of beating these are your single side fungicides, your group, 7,11, and 3. And I’m going to talk about a couple of different things that can happen, particularly in these wet seasons.
We’ve had, we’ve had a lot of rain early on and a lot of rain at petal fall. I want everyone to be mindful of moldy core. It’s fungal colonization of the seed area. You can kind of see it around in the little cavity around the seeds. And this will usually occur from sort of latent infections from bloom to early fruit development, particularly at petal fall, is where this is going to cause a problem. You’ll see mycelium in and around the seed coat. It’s gross, but it’s not a major health concern and it doesn’t could be any number of sort of junk, mildly pathogenic fungi that are present in your orchard, alternaria, botryosphaeria, penicillium. And then these infections will happen early on in a lot of wet weather, in the early phase of fruit development and or petal fall. You’re not going to see them now. You’re going to see them post-harvest and storage, and they’re really just going to be confined to that flesh around the core of the apple. They’re not going to move out, but they will throw your apples out of grade and can lead to load rejections.
There’s another problem we’ll talk a little bit about later as well, that’s a little bit of a later concern as well, but let’s talk about what’s coming up. Fly speck/sooty blotch, bitter rot, anthracnose, black and white rot caused by botryosphaeria. Bitter rot is an anthracnose caused by Colletotrichum. You can kind of see some nice black rots here. It’s going to be smooth. It’s going to be a spreading lesion. The black rot will make a more firm lesion, kind of feel kind of like an oily peanut, while the fly spec will make little tiny specks or little blotches of, um, fungal conglomerations and sporulation of mycelium that will look kind of like their soot on your apples. These also latent infections to early fruit development and sort of the stages that we’re in now. Um, things can begin to cause an infection on the sort of fruit and have these sort of fruit blemish diseases as it constantly dumps about one inches of rain in 15 minutes, um, every other day with these thunderstorms, it might be something to know about now. It can get worse and pre harvest in the fall and fall rains, or wounding of mature fruits, when the birds and the herbicides get involved, that’s particularly where you’re going to see your bitter rot and your black rots and things really happening later.
The fly speck/sooty blotch infections can sort of happen now, and this is going to show up post harvest in storage. Once they get stored, once they get cooled, and once things get more humid than they are outside, and it’s going to lead to more pack out rejections. They can be a bigger problem on sandier areas, particularly in the Hudson Valley or Long Island. If you have sandier soils, these heavy storms can blow the sandy or dry soils that dry and bake off during the day, with the 90 plus degrees of heat, things get windy, a storm comes up, blows these through the area. One micro wound hits, or a small little droplet of herbicides, and the next thing you know you have sunken sporulating bitter rot lesions. Some cultivars are incredibly susceptible and can completely collapse on, on their side, leading to something that looks bizarre and unlike anything you’ve ever seen before. Big problem in organic operations or anything that relies heavily on multisite protectant fungicides.
As we move away from Captan, these single sites are going to be more important, and this is how you generally manage them, petal fall fungicides. This is why I’ve been sort of shunting my recommendations of saving single sites for petal fall and later beyond and then the summer fungicide cover programs, I think we’re at a good phase where it might be time to include one or two more single sites, if you have any left. And then always that final one is the harvest single site fungicide application right before the REI that you can get on and put your feet, uh, your fruit on their best possible trajectory before they go into storage. There’s some materials that can do that. Talk a little bit about that a little bit later.
The other thing that can kind of look like moldy core that we saw earlier is fungal mycelium is something like callus core. If you get a lot of rain, the fruit development can be a little strange. You can almost see something that looks a little bit like water core, around the apples is an example I’ve seen before is Fuji, and they will have this crystalline callus tissue around the seed cavities. It’s not actually fungal mycelium, but it’s crystalline callus tissue and it can kind of look firm. It’s going to be crystalline, it’s going to be crunchy, it’s not soft like fungal mycelium is absolutely no health concern and it provides no flavor. It’s a physiological concern that is often mistaken for moldy core in certain varieties, such as in the Fuji shown here, it’s not necessarily disease problem.
So sort of summarize our summer fruit and, and of course, foliar diseases. These will also manage these as well that I’ve talked about earlier. I think strong program really going into that petal fall through second cover, the single site fungicides, including your SDHIs, your group 7, your DMIs, your group 3s, and your mixes of SDHI/QOI products, your 7-11s, those will become really important at the end of the season whatsoever.
Key timing for another mentioning. This is also a great time to get your hands on the apple blotch, diplocarpon and Marsonnina and initial summer disease inoculum for fly speck/sooty blotch and rots. A lot of some of the earlier studies I’ve done looked at applications from petal fall to the second cover, just, just these. And these were as effective as a full program of biopesticides and Captans. That’s considering the 2.5 pounds to the acre of Captan 80, plus phosphorus acid. Just a couple applications around these early summer cover timings can be incredibly effective.
What else do we have next? Things all nicely out of order, and when you get into third through fifth cover, consider making two applications if you still have any left of the single site fungicides, particularly since we’re having this rainy summer. QOIs, SDHIs, and DMIs should really slow down that apple blotch, Diplocarpon is the name. Anamorph used to be Marsonnina, that’s why it had a previous name of Marsonnina blight, and it should prevent a lot of defoliation for harvest. It looks like third through fifth cover, one to two of these, plus the petal fall to second cover timings of your single site fungicide should really keep your trees from defoliating at harvest. If we have heavy rains, having every night that dumps about an inch, 1.5 to 2 inches, you might need to make another one. Some of these things are quite heavy. You’re going to have to really measure the amount that these thunderstorms dump on your crops and you might need to consider a tighter interval for your fungicide applications. If you have a light period, I still recommend the Captan 80, 2.5 pounds per acre with phosphoric acid. Watch your sensitive varieties. If you have some Captan sensitive varieties, use a liquid one, use a larger application volume of water should also knock down on any potential troubles.If you don’t like Captan, we don’t have Ziram anymore, but you can you can really go for the Double Nickel. I’ve had good luck with Double Nickel, Oso particularly, Howler, and Theia for some of these summer diseases as well.
All right, and as we go into the pre harvest period, I’ll probably bring this back up again. In all cases where your summer programs finish strong, find one of those low PHI SDHI/QOI combinations or DMI ones. If you happen to have Cevya and Merivon, have a zero PHI, which means you can apply them, then send the crews in there to get them and put them in the storage and pack them out. Luna Sensation, Inspire also excellent choices as well, more like about 14 day PHIs. If you can make that final strong with the season, you’ll really keep those diseases down. Now you might be asking like, oh, why are we using all these single site fungicides post bloom? How am I going to get through the apple scab season? I tend to like to recommend in the early season how to save these things as use copper early and use protectants like Captan and Mancozeb at that point from green tip to bloom. Use your copper as often as you can to get through that start of the season, then Captan/Mancozeb and then once you start to hit bloom, then save those SDHI, QoI, DMIs then. And then of course, if you have five days of rain or awful weather in the early season, use that Scala or Vangard, or use up your two applications that you have pre pink of Syllit and those should really take care of your single site fungicide concerns.
So in summary, this is sort of what we’re looking at again. As I mentioned before, go hard to the coppers in the early season as you’re moving from bud break into, you know, all the way up into pink, use your Captan and Mancozeb or Captozeb, and then really wait until petal fall to start using single site fungicides. Particularly if you get a lot of these weird seasons where we’re getting a lot of rain dumps early on, you don’t want to see these things.
What will I be talking about next time? Sadly, it might be summer canker diseases. We’re going to need to prune things. I’m glad I held off on sidewall shearing my Evercrisps. I know I need to wait until July and I was getting anxious and I’m glad it did because it’s constantly raining and what I don’t want to see are a bunch of cankers after I end up trimming those plants. All right, we’ll talk about cankers and stuff next time.
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 as usual I’ll be sharing information aggregated from the regional specialists and my own observations.
Last week we had appropriate weather for the summer solstice, really hot conditions with highs in the upper eighties to nineties [°F] with extreme humidity across the state. We had reports of sporadic or isolated storms across the state, with heavy wind reports and a few reports of damage in isolated locations (these reports came from individuals). You can also see storm reports on the NOAA National Weather Service Storm Prediction center website, which we’ll link in the show notes. Rainfall accumulation according to NEWA weather stations ranged quite a bit from location to location, just more than a 10th of an inch in some places and over three inches in others. Most of that rainfall occurred in isolated storms at the end of the week or over the weekend. Fortunately, in most places we are now caught up on soil moisture because of that rain, so that’s kind of a relief. We’ve now moved into a cooler trend with lots of wind, a little bit less humid, with more rain expected at the end of this week, followed by a return to very warm conditions. The six-to-ten-day outlook in the NOAA Climate Prediction center predicts near normal temperatures during this cooler trend for the rest of the week, with slightly higher than average or average precipitation expected. Then the eight-to-fourteen day, little bit longer outlook, predicts a return to warmer than average temperatures and close to average precipitation.
Looking at phenology across the state, it’s a pretty compressed season with very similar phenology across the state. We’re near terminal bud set on most apples in the Hudson Valley, and other regions are right behind that. Fruit is coloring and sizing well. In the Hudson Valley, apples are beginning to color, continuing to size. Cherries are harvesting, peaches and nectarines are continuing to size, and harvest is almost starting on very early varieties. Looking a little bit at berries, June-bearing strawberries harvest wrapped up really quickly with the heat last week. Other berries are ripening quickly and many of the u-picks in the region opened over the weekend. In western New York, the Lake Ontario region and in the Capital Region, things are looking pretty similar. Degree days and phenology are pretty similar, maybe a couple of days or up to a week behind, and in the Champlain Valley just a little bit behind that. As I said, things are pretty compressed this season with phenology not ranging too much across the state from region to region.
Now looking at some upcoming pest events: oriental fruit moth the second flight has started throughout the state, mostly in the last week. So at this point it’s a little bit too early for management targeting that insect. Codling moth in the Hudson Valley, the biofix was 5/6 in Highland and the accumulated degree days since the biofix until June 23 are 891, so the second generation is likely emerging at this point. In the Champlain Valley peak flight and egg hatch of the first generation is happening around now, if not a little bit earlier. And so if it’s been 10 to 14 days since your last application, recommendations are to apply a material in your next cover. Remembering that the first insecticide targeting larvae for this insect is around 200 to 250 degree days base 50, and then an application should go on around this time, and then again 10 to 14 days later. Obliquebanded leafroller trap continues, sustained flight has been recorded in most places throughout the state for a couple of weeks now. Continue to monitor your growing terminals at around 600 to 700 degree days base 43 after your biofix and so in most areas in the Hudson Valley and likely soon in the Capital Region and in western New York, that period is now. In orchards with a history of heavy pressure or infestation, insecticides are recommended around 350 degree days base 43 after the biofix, and then a second spray again 10 to 14 days later. Worried about that second application now in the Hudson Valley and Lake Ontario region, and next week for the Champlain Valley.
Apple maggot trap captures have been reported in a couple of locations in the Hudson Valley. It feels a little bit early, but these mid-June trap captures have been recorded across the northeast for a couple of years now. And so historically, guidance has been to put out traps on the 1 July, but now we’re thinking maybe a little bit earlier, maybe mid June would be a more appropriate timing, especially in more southern sites or earlier sites across the state. Fruit is still not susceptible at this stage. Females will take a couple of weeks to mate and start laying eggs, and we’re still well below the threshold for this insect. The threshold would be five flies per trap for baited traps.
Brown marmorated stink bug has been captured in the Hudson Valley and other places in eastern New York as well as western New York, so we know that that insect is active. At this time, we’re recommending about four insects per trap as a threshold for management.
There has been increasing aphid activity across the state, reported both green apple aphid and rosy apple aphid, as well as woolly apple aphid continues to be active and increase both in number and size of colonies in the places where we are looking. These insects are also moving, moving away from the pruning cuts where we find them earlier in the season, out toward the leaf axils. We’re continuing to see leaf hopper activity, mullein plant bug activity. San Jose scale crawlers are emerging now in some of the cooler parts of the state and have emerged previously in warmer parts of the state.
There have been a few reports of mite outbreaks, both European red mite and two spotted spider mite, in orchards across the state, most likely due to the hot, dry, dusty weather over the past couple of weeks. During June, we’re using a threshold of two and a half mites per leaf as a positive leaf for mites. And then there is a sequential sampling procedure that you can find in the Cornell guidelines. Apple leaf curling midge continues to be detected throughout a few sites in different parts of the state. This is an emerging insect that we’re still learning a little bit about. And dogwood borer flight continues to be detected in many locations, so we’re keeping an eye on that.
Looking at diseases, we’re continuing to see pretty severe powdery mildew across the state because of that hot, dry, humid weather, so dry, meaning there’s no freestanding water. This pathogen can’t survive in freestanding water, so rainfall would be bad for continued infections. We are continuing to hear a few reports of fire blight strikes throughout the state, although in general it doesn’t seem that there has been extreme pressure of fire blight this year. So keeping our fingers crossed on that. Primary scab season obviously is closed throughout the state, but keep being vigilant for any infections which could lead to secondary infections throughout the rest of the season. We’re seeing more and more rusts in places where they’re not being managed well, and we’re starting to think about summer diseases. So flyspeck and sooty blotch as well as black rot have been reported in a couple of locations. Expect to see signs of other fruit rots in the near future.
Spotted wing drosophila counts continue to increase. They’ve been detected both first and sustained captures in most locations throughout the state where we’ve been monitoring for that insect. They started a little bit earlier than usual, which is pretty expected given the early wet conditions this spring and the really warm conditions over the past couple of weeks. We’re detecting them in both red jar traps and on red sticky cards. In some locations, the insect captures are still relatively low, but in many locations those populations are rapidly increasing, which is pretty typical of this insect. So we have posted the quick guide for insecticides for managing this insect on the Cornell Fruit Resources page, which we’ll link in the show notes. And if you’d like to continue to get updates about this insect, as well as other berry pests, we’d like you to subscribe to the new blog, the new Berry Pest Monitoring Network, and so to do that, you’ll need to visit the blog, subscribe your email, and then you’ll have a follow up email that you need to respond to in order to confirm your subscription. Information about all that will also be included in the show notes.
And now here are the current degree days in the major fruit producing regions of the state. Throughout the season, we’ve been aligning this information with previous work done by Art Agnello relating to McIntosh phenology and degree days with 43 Fahrenheit based temperature. In Geneva, we’re at 1614; Highland at the Hudson Valley Research lab, 1728; Clifton Park, 1585; Peru, 1363; Medina an inland site 1568; Appleton North, a lake site, 1416; Fairville the Apple Shed and inland site, 1508; and Williamson DeMarree, a lake site, 1511. That’s all for this week, and good luck until next week.
| Phenology & DDs for NY NEWA Stations from 1/1 – 6/24 | |
| Station | DD Accumulation |
| Geneva | 1614 |
| Highland (HVRL) | 1728 |
| Clifton Park | 1585 |
| Peru (Forrence) | 1363 |
| Medina – Inland | 1568 |
| Appleton North – Lakeside | 1416 |
| Fairville (The Apple Shed) – Inland | 1508 |
| Williamson (DeMarree) – Lakeside | 1511 |
Phenology & DDs for NY NEWA Stations from 1/1 – 6/24
Station || Stage || DD 43F || Weekly Rainfall (in)
Geneva || fruit sizing || 1614 || 0.9
Highland (HVRL) || fruit sizing || 1728 || 2.28
Clifton Park || fruit sizing || 1585 || 1.09
Peru (Forrence) || fruit sizing || 1363 || 1.91
Medina – Inland || fruit sizing || 1568 || 0.54
Appleton North – Lake || fruit sizing || 1416 || 0.36
Fairville (The Apple Shed) – Inland || fruit sizing || 1508 || 0.13
Williamson (DeMarree) – Lake || fruit sizing || 1511 || 0.17
*all DDs Baskerville-Emin, B.E
Upcoming Pest Events
Pest/Phenology Event || DD Base 43˚F || Approx. Date
ERM Sample – 2.5 mites/leaf || 1-Jun
OBLR traps set out || 1-Jun
OBLR – 1st adult catch || 884 ± 90 || 9-Jun ± 6 days
OFM – 1st flight ending || 825* ± 126* || 12-Jun ± 8 days
Peachtree borer – 1st adult catch || 1032 ± 266 || 15-Jun ± 11 days
San Jose scale – 1st flight ending || 1039 ± 182 || 16-Jun ± 8 days
Black stem borer – 1st flight ending || 1056 ± 198 || 19-Jun ± 9 days
STLM – 2nd gen. 1st adult catch || 1063 ± 91 || 16-Jun ± 6 days
San Jose scale – 1st crawlers observed || 1124 ± 91 || 19-Jun ± 8 days
Dogwood borer – 1st adult catch || 964 ± 230 || 12-Jun ± 9 days
American plum borer – 1st flight ending || 1344 ± 144 || 29-Jun ± 7 days
Apple Maggot Traps Set Out (in orchard) || 1-Jul”
ERM Sample – 5.0 mites/leaf || 1-Jul
Comstock mealybug tape traps set out || July 1 (ENY), July 15 (WNY)
OFM – 2nd flight starting || 1180* ± 136* || 29-Jun ± 5 days
OBLR Summer Gen. 1st Sample || 10-Jul ± 5 days
STLM Summer Gen. 1st Sample || 9-Jul ± 7 days
RBLR – 2nd flight starting || 1367 ± 105 || 29-Jun ± 6 days
AM – 1st catch || 1509 ± 285 || 4-Jul ± 12 days
Lesser peachtree borer – peak catch || 1234 ± 470 || 25-Jun ± 19 days
STLM – 2nd flight peak || 1563 ± 207 || 6-Jul ± 8 days
Codling moth – 1st flight ending || 1557 ± 262 || 6-Jul ± 12 days
Peachtree borer – peak catch || 1579 ± 465 || 7-Jul ± 19 days
Lesser appleworm – 2nd flight starting || 1768 ± 339 || 14-Jul ± 12 days
OFM – 2nd flight peak || 1450* ± 147* || 11-Jul ± 9 days
American plum borer – 2nd flight starting || 1850 ± 290 || 16-Jul ± 11 days
RBLR – 2nd flight peak || 1721 ± 232 || 13-Jul ± 7 days
San Jose scale – 2nd flight starting || 1804 ± 170 || 15-Jul ± 8 days
Codling moth – 2nd flight starting || 1887 ± 313 || 20-Jul ± 13 days
Dogwood borer – peak catch || 1611 ± 226 || 8-Jul ± 10 days
STLM – 2nd flight ending || 2167 ± 177 || 28 Jul ± 8 days
American plum borer – 2nd flight peak || 2290 ± 285 || 1-Aug ± 8 days
OFM – 2nd flight ending || 2044* ± 233* || 31-Jul ± 7 days
*Base temperature for OFM 45F
NEWA Help Desk Frequently Asked Questions and Table of Contents. https://help.nysipm.org/hc/en-us/categories/16994462926231-NEWA-Network-for-Environment-and-Weather-Applications
Quick Guide for Apple Insect Pests https://help.nysipm.org/hc/en-us/articles/23290226665751-NEWA-Quick-Guide-for-Apple-Insect-Pests
NY Tree Fruit Pest Monitoring Network
https://blogs.cornell.edu/treefruitpests/
Interested in collaborating and contributing trap capture data? Contact Anna Wallis aew232@cornell.edu
Berry Pest Monitoring Network – NEW Blog!
https://blogs.cornell.edu/berrypests/
Quick Guides for SWD Management