This post is a text digest of the new Scaffolds Podcast. To listen to the original, visit the following link: Scaffolds Podcast  

 Entomology Update with Monique Rivera 

This week I’m going to talk to you about IPM and some innovations in IPM that may be on the horizon. I’m also going to talk to you about peptides as a primer for next week, because next week we’ll be talking to Dr. Michelle Heck for my segment, and we will be going over some innovative new technology to assist in curing disease and tree fruit.  

But for now, let’s hop into the future of IPM and where we might be heading. So, when it comes to pest identification and monitoring, potential innovations here could include the use of advanced sensors, artificial intelligence, and machine learning algorithms to detect and monitor pests more accurately and efficiently. I think that the closest place we are to that is camera based traps, where you’d be able to check the trap via some sort of interconnectivity to a website or to an app on your phone. I think that is very close to being developed. In California, I was working with some computer scientists to train machine learning algorithms to detect pests, and I do think that’s a pretty long ways off in terms of being able to use that effectively and across systems.  

So next is cultural controls. This involves implementing practices that could make it difficult for the pests to thrive. Examples of this – that are not relevant necessarily to apples – would be crop rotation, soil management, and then our pruning practices. Innovations here could include the use of precision agriculture techniques. I think we’re having that discussion on the horticultural side. And this really is specifically addressing precision irrigation and fertilization when you do this, helping to reduce pest susceptibility through optimizing the health of a plant. 

For biological controls, this is just the idea that you would use existing natural enemies or supplement natural enemies of pests. This could be predators, parasitoids, and then this would help reduce their populations overall. Innovations here could include the use of GMOs. Modifying organisms to be more efficient, or modifying organisms to produce natural pesticide compounds, obviously, of course, integrating genes that would enhance the effectiveness of the biological control agents. I think we’re a very long way away from that since we can’t even get GMOs in plants. I think there’s a lot of fear around this, but nonetheless it will happen somewhere in the world if we don’t try to innovate in this area.   

When it comes to chemical controls, innovations here could include the use of precision application technologies such as drones or autonomous vehicles to apply pesticides based on specific detections which would help reduce waste and minimize environmental impact. And then I think what’s most exciting are the integrative approaches.  

So taking all of these different ideas and trying to combine them, innovations here would be advanced decision support systems. There’s a lot of discussion on the research side about development of these. However, a lot of it, I feel like outside of NEWA has not made great contact with the actual producers. The idea would be that these could provide real time recommendations especially for timing of pest control strategies.  

 Another innovation that could be overlaid on other different types of approaches in IPM would be this technique called RNAi. This stands for RNA interference. This is a natural process that occurs in cells to regulate gene expression. RNAi is essentially a way to turn off certain genes by preventing them from being expressed. In agriculture, RNAi technology has the potential to be used as a tool for pest control. And the idea is that by introducing these small RNA molecules that are complementary to specific genes in pests, it would be possible to potentially silence those genes and prevent the pests from causing damage to crops. So, for example, researchers have used RNAi to target genes in pests such as corn rootworms and western flower thrips. Introducing RNA molecules that target specific genes in these pests, the researchers have been able to reduce their population levels and protect crops from damage. I also think this is quite a long way off but is a good thing to have on your radar as these ideas begin to get more frequently introduced. The advantage here is that it’s a highly targeted approach which means it only is going to affect the pest species that is being targeted. At least that’s what’s thought of for now. In particular, it will not harm non-target beneficial insects or organisms that are outside of that target species. And RNAi-based pest control is considered to be environmentally friendly especially and in particularly because it does not involve the use of broad spectrum chemistries. It’s still in the early stages of development and testing, but if they can figure this out across systems it could be a very powerful tool for sustainable agriculture in the future.  

So in addition to that, let’s switch gears a little bit and talk about peptides. So, plants use peptides which are small molecules made up of amino acids to defend themselves against herbivores. So we’re talking about insects that eat plants and some of these peptides are toxic to herbivores and can prevent them from eating on the plant. Other peptides can attract predators or parasitoids of the herbivores, which can also help reduce population levels. So one class of peptides that plants use for defense are called systemin peptides. These are peptides that are produced in response to damage by herbivores and can activate internal signaling pathways inside the plant to upregulate defensive compounds. So if you think about, for example, marigolds, they have this very specific scent and when they’re chewed on, that scent is released. So that’s an easy example. But across many different plant families that you’re probably familiar with, there are these scents given off at the same time as these peptides are being upregulated.   

There’s another class of the peptides that can be used for defense called defenseins, and these have antimicrobial properties and can be toxic to herbivores. So in addition to producing peptides that are directly toxic to herbivores, plants can also produce peptides that attract natural enemies of the herbivores. For example, a parasitic wasp. So a parasitic wasp would be attracted to those signals, those scents, and they would lay their eggs inside of the insects themselves on the plant. By an indirect manner of attracting these natural enemies, plants can reduce the overall damage. In short, this is a very complex idea that for every individual issue researchers will need to dig into what about that plant or what of other plants could be added to the target plant to create these antimicrobial or herbivore defense systems. So plants definitely depend on peptides and I think this is a new target way of innovating to fight back against plant diseases. So this can include apple scab and fire blight, which is on all of our minds right now.  

Next week we’ll be talking to Dr. Michelle Heck. She is a researcher at USDA, but based in Ithaca, and she is leading a very, very large grant through USDA to high throughput screen peptides that are being discovered over time for various plant diseases. So I’m excited to talk to her next week.   

Pathology Update with Kerik Cox and Liga Astra Kalnina  

I will group the Hudson Valley and Long Island together because for both of them, almost all ascospores have been discharged for the season, somewhere between 85 and 95, depending on where you are in the region. So the primary apple scab season is almost over. Next time these two regions get a big rain event, the last of the spores will probably get pushed out. So currently I would like to say there is no risk for apple scab infection for the week, but soon it might be time to start scouting for scab lesions on the leaves to monitor for conidia infections.   

When it comes to fire blight, NEWA is saying that for most of the stations, the degree day accumulations for most stations in the region are estimating that the bloom period is over. However, if you still have open blossoms for later blooming cultivars or have some stray flowers, there is a high risk of fire blight infection this whole week, with extreme risk of an infection from the May 12 until May 15. As the highest EIP values are above 700 and the highest TRVS are above 200. What I would like to say is that even though these numbers may seem high, you need to take the orchard history and cultivar susceptibility into account. So if you have a lot of cider apples that are still blooming, you might want to really make an application of Streptomycin or Kasugamycin. Kasugamycin is a good alternative, as well as Blossom Protect, if you have confirmed Streptomycin resistant fire blight in your orchard.   

So the one that I really wanted to talk about today, Champlain Valley, and especially about apple scab, not fire blight. Currently NEWA is showing that there are no apple scab infection periods predicted for the week. However, there might be 18% of ascospore released on Friday if it rains. So if it is raining, please make sure to make a fungicide application. You might even want to do a single side application Friday morning if the forecast changes and it’s predicted to rain. If it’s not raining, these ascospores will not get ejected, so you can maintain your desired fungicide coverage. The risk for fire blight infection is very low if your flowers have yet to be open. There’s probably no need for an application, but if you have earlier blooming cultivars up there, then make sure you make an application. Maybe Friday morning could be a good time to make an application, maybe even Blossom Protect if you like a biological.  

The last one I like to talk about is Capitol District. So the same thing. Weather is getting warmer, so end of the week, most blossoms, if they’re not yet open, will be fully open. So there is a high risk of fire blight infection period predicted from tomorrow, that is May 11 until May 15. So even though the highest TRV for the week is predicted to be 492 on May 13, it does fall in the extreme category. But like I said before, don’t let the numbers scare you. You have to take the orchard history and cultivar susceptibility and what kind of cultivars you have into account before you’re making your applications. So as for apple scab, there’s currently no risk of infection, so you can maintain your desired fungicide coverage. This week might be a good time if you have not had time to make a cover spray with all these big apple scab infection events for the past three or four weeks, might be a good time to do a cover application.  

We’ve already heard the update on the risk predictions for the week, and yeah, we’re finally having bloom statewide, and yet now we have warm days, so the fire blight panic can now set in. The nights are pretty cold, which can really slow down the epiphytic populations, but the daytime heat can really cause everyone to sweat, so to speak. There’s a lot of advice and suggestions on that out there on how to deal with fire blight at bloom. Here’s some guidelines that we presented and refined over the years based on some advice from our own work, that of Dr. George Sundin at MSU, Dr. Juliet Carroll Cornell, Debbie Breth, former fire blight scientist from Cornell, and Dr. Anna Wallis from New York State IPM. We’ve continued to refine and update these guidelines for managing fire blight focused primarily on young plantings. We won’t talk about that today. I’m going to present the guidelines in three parts.  

The first one will just be general guidelines for season long management, and then I’ll talk about new plantings and nurseries. But first, let’s just start with the general guidelines for season long management of fire blight in apples. Okay, first one, during bloom, always follow fire blight forecasting systems, such as the two models that are in the NEWA system for fire blight. Make sure to always time applications during the high risk weather and get as close as you can to that high risk weather as you can and keep your crop protected. You don’t want to be after the rain. You definitely want to be before the rain. Now it may not be necessary to apply an antibiotic each time a high risk is forecast. But it’s probably, unless we have a really long bloom like we’re having now, it may not be necessary to get any more than three applications in for Blossom Blight. Right now in our own blocks, we really aren’t applying for Blossom Blight yet. Friday looks like a day that I would really consider protecting my own blocks.  

So, first part, let’s say you’ve had no history of streptomycin resistance more than three seasons. So what we’re recommending is if it’s before a high risk “extreme” or “infection” (those are those sort of extreme terms that the models like to use during bloom) you can start right before this weather to go ahead and make your first application of streptomycin. You can put in Regulaid with that first application to really enhance its effectiveness and uptake. Yes, if you get later in the season, you might get a little bit of yellowing around the edges. Well, all that’s telling you is that, okay, yeah, I got a little yellowing in my leaves, but you know what? It means you also have the material inside the edge of the crop. So if it’s particularly rapid drying conditions, the Regulaid can be beneficial. We’ve finally left that cloudy, overcast weather, so might as well give it a shot. But don’t be too worried if you see a little bit of the yelling that’s associated with it.  

Now, if you need later applications, you can continue to use strep, but maybe in that second one rotate in kasugamycin. It’s marketed as Kasumin 2L. And consider just one of these for resistance management purposes and particularly if you have concerns about the effectiveness of streptomycin, this will be the chance to send something in for antibiotic testing. If you’re going to go with kasugamycin, make that application towards the evening. It can break down. Now, can you just oxytet with strep? You can, try to hit the full rate of both of those materials. Oxytetracycline is a bacteriostatic. It means it doesn’t kill. What it’s going to do is stop the replication. It’s going to stop that build-up of epiphytic populations until the flowers dry out. Basically that’s how it’s working. It’s just stopping the growth. They could start right back up again the moment the material is used up. So it’s not a killer, but you can mix the two. I would say you can use that mixture or you could use kasugamycin, whatever is cheaper for your particular operation and whatever you feel more comfortable with or whatever you’ve purchased.   

Okay, now things get scary if you have had streptomycin resistance in the last three seasons. At this case, we’d like to consider going with a different antibiotic. For the most part, there’s no point putting streptomycin back in the tank. I would either go with a single application of kasugamycin right off with the big weather. You can include the penetrating surfactant Regulaid. I’ve never seen any marginal leaf burning. And if you do this, just be careful. Try to avoid that alternate row middle spraying. Obviously you can’t go after petal fall with kasugamycin. Now it can break down rapidly in sunlight. So make sure if you’re going to do it, make sure it’s overcast or go to the end of the day if you can to do it.   

Okay, what’s the other option? This one actually works fairly well. You can either go with a Blossom Protect, and as long as you’re not moving into petal fall, and as long as you don’t have overcast dry misty weather, you probably aren’t going to get a lot of russeting from it. We’ll go in at the recommended rates. It’s fully allowed for your organic plantings as well. You can completely and effectively manage fire blight with this product. The alternative would be to go for oxytetracycline as well. If you want that second antibiotic, you can just go oxytet at the highest rate in this kind of drying weather. It’s going to do well. Remember, fire blight can take cold, but it can’t take drying out. And even if you do slow it down and stop it from growing, you may get enough drying to keep flowers from getting infected. If you need the third one, I would hit it hard again with that Kasumin 2L for that first and last, and maybe bring in your Blossom Protect in the middle. Now you can go Blossom Protect the entire time or you can go oxytet if you have a lower infection period.  

Okay, so the next thing one should do, let’s say we finally get out of bloom, scout around and if you see any fire blight strikes, it’s best to kind of prune them out. Make sure to do it, just get them out of there, can burn them if it’s allowed, but leaving them to dry out works as well. Fire blight hates drying and right now it’s recommended to get as close as you can into healthy wood. Going maybe two and third year wood is best to try to get beyond that water soaked margin. If you see any fire blight, prune it out.   

Now, of course, you have to be careful because you can stimulate new growth. If fire blight hits that central leader, you’ve got to get rid of the tree. It’s probably best to remove it. Now one of the things that I’ve liked, that I’ve seen recently, it’s very effective, is just to cut the tree off at the scion and let the tree sort of just hang there on the wire and dry out and let your rootstock graft union dry out as well. Dead trees won’t ooze. If they’re already oozing you’ve got to get the tree out of there. But if it hasn’t started oozing yet and you know it’s dead, you can kind of let it dry out in the orchard and of course you can replant there later.  

As we’re moving into the post bloom period, it’s time to consider the prohexadione calcium Apogee or Kudos for your shoot blight management, particularly if the block is vigorous and highly susceptible. Shoot for 6 to 12oz per 100 gallon if it’s a big tree. If they are short small trees less than five years old, you might want to go 3 to 6oz per 100. Apply when the trees have about one to two inches of shoot growth, and then make another application later. That’s the tried and true method. There are alternative programs, I’ve talked about them in the winter meetings, with using a 2oz prohex with 1oz rate of Actigard. That’s fine. That’s a better program for those really young one to two year old high density trees. You’ll get a little bit of synergy from the two. That is considering you started that little two plus one program around pink.  

Okay. Can you use copper post bloom? Yep, you can use a post bloom into the summer, find the right coppers that have post bloom labels. And remember, it’s not going to do anything on existing shoot blight infections. The bacteria is inside the shoots and it is just moving. And of course you’ve got to be very careful. Always have adequate drying time. Don’t do it on one of these overcast days or you will scratch up the fruit. You can always use some hydrated lime to reduce the potential of phytotoxicity from copper. I’ve talked with a bunch of people, I don’t know if there’s a particular lime that is OMRI listed, but I think there are options if you’ve talked to local distributors, or you can find out if lime is something that you can just use by itself. Been sort of a tricky for some of these copper mixes. Now remember, the other thing that can happen is you’re going to have to go on a regular schedule, particularly if the terminals are moving because they will outgrow the protective residues of copper and any of the coppers that mix really well seem highly soluble. These are going to be ones that aren’t going to stick around and often have that post bloom application labeling. And then of course if you can get the terminal bud set, you might be fine, but if your trees keep growing into the fall, you can have trouble.  

Now can you save a planting? Sometimes. But I wouldn’t necessarily recommend this because you leave a lot of junk in the orchard to cause more problems later. If things look like they’re bad and you think, I got to try to save this block, you can hit it with prohexadione calcium at the highest rate. Give it five days as you sort of nervously bite your fingernails, then come out and prune. And then you might have to slow it down again. You need that five days to allow the product to get taken into the trees. Then you could prune. You might need to do it every two weeks, and you might need to hit it again to slow it down if your pruning stimulates additional shoot growth. If you need to interplant apple trees in existing orchards killed by fire blight, you can plant these in the late fall, just so that you don’t end up killing your new interplant trees as fall infections happen. I thought I was going to get smooth myself and plant my Evercrisp in August, and I got fire blight this year in our very warm fall all the way into September and October. I was able to stop it because it was cooler. But try to get through the season before you try to do those interplants. And fall planting can be a way to escape some pressure, but not if it’s a really, really warm year.  

State of the State with Anna Wallis 

This is your weekly roundup of Degree Day accumulations and phenology from the major fruit production regions around the state. As always, this information is aggregated from the regional specialists around the state, NEWA, and my own observations. Remember that degree days are a measure of heat accumulation, and we’re using them to predict pest activity and tree phenology early in the season. We’re continuing to keep track of Degree Day base 43 Fahrenheit since January 1, which means we’re only accumulating degree days when temperatures are above 43. It’s really important to be clear about what degree days are being used. Many of the insect models used by NEWA, for example, use Degree Day base 50 and accumulations since Petal Fall. This is much more precise of an indicator for specific insects and for orchard sites in a given year. However, we’ve also tracked season long accumulation of Degree Day base 43 and corresponding phenology and pest activity for many years. So this is also a good indicator.  

This week we’ve had very welcome warm weather across the state, with slightly more heat accumulation recorded by NEWA stations in the eastern part of the state, meaning the Hudson Valley has moved pretty quickly, and northeast New York is nearly the same phonology or slightly ahead of western New York production regions. In the Hudson Valley this week, most varieties are at Petal Fall or fruitlets are beginning to size. In the southern area, fruitlets are in the range of 3.5 to 4.5 millimeters, with a few kings reaching 6mm in Ulster County and 7mm further south. That was at the beginning of the week on Monday, so things have probably moved a little bit since then.  

 In the Lake Ontario region, sites closer to the lake began bloom over the weekend with significant numbers of blossoms opening earlier in inland sites. Sites close to the lake had just begun bloom on Monday and bloom has continued steadily this week with the warming temperatures in Geneva this week. Also inland McIntosh and Gala came into full bloom early this week. Peaches, apricots, plums, and cherries are all just beyond petal fall with fruitlets beginning to size.  

In the Capital Region, it’s still in bloom with petal fall beginning on Macs and earlier varieties at the beginning of the week and continuing to progress. In the Champlain Valley, things were in bloom at the beginning of the week with Mac starting to open up in Peru about Saturday and a few Honeycrisp and Gala opening up on Sunday.  

 Now I’ll give you a rundown of the degree day accumulations in NEWA weather stations throughout the state. On average, Macintosh bloom usually takes place in the upper 300s to low 400s, and petal fall is about in the mid 400s to low 500s.  

 As of the end of the day Tuesday 5/9, DD accumulations were: 

 There are quite a few pest events to be looking out for during this period. Obviously fire blight is the number one during bloom, but also a lot of insects are beginning to be active in Geneva and western New York as well as the Capital Region and the Champlain Valley. The first OFM captures were at the beginning of this week and this is right on time. Usually that occurs at about 220 to 320 degree days base 43. It seems to be beginning just a tad later in that range this year, probably likely related to the cold temperatures before this week. We’ve also noticed a little bit of leaf roller damage and spotted some tiny early instar caterpillars in the trees. Plum curculio is likely to be out soon with a few warm nights and lots of moisture in the soil. Tarnished plant bug has been captured in a few sticky traps based on observations of pest activity and corresponding average degree day range over the past few years. Here are a few other things that should be taking place around now in the range of 300 to 400 degree days.