Episode 4 - Pecan Nut Casebearer & Early Season Insect Management

With pollination complete, Georgia pecan growers are determining how to manage pecan nut casebearer.  Dr. Apurba Barman from the UGA Department of Entomology joins this week's podcast to answer early insect management questions. Has casebearer reproduction been established across Georgia? Should all varieties of pecan be treated the same? Why are the western and eastern pecan growing regions so different in terms of casebearer damage?  Do trap captures of casebearer correlate with damage?

Additionally, UGA Horticulturalist Dr. Lenny Wells and Dr. Barman discuss an historical context of aphid management from Texas to Georgia. What should pecan growers do if adult black pecan aphids are present in the month of May?

Finally, Dr. Barman addresses his new research on prionus root borer to determine a new way of control and if young pecan trees may also be susceptible to its damage.

Transcript

SPEAKER_03 0:09

Whether it's Pecan or Pecan, we cover it all. Orchid management, growth and development, test management, economics, related agent specialist, scientists, county agent, industry representatives, and growers brought to you by the University of Georgia Pecan team. In a nutshell, the Pecan podcast. Welcome to episode four in a nutshell, the Pecan Podcast. I'm glad uh you can join us today. I'm Andrew Sawyer, area Pecan agent in East Georgia. I'm Lenny Wells, extension specialist for Pecans at University of Georgia. We are your host. Well, I'm glad to be on today, Lenny. It's time to do number four. And great topic today. We're going to jump into insect control. Yeah, we got some help with this one too. I'm excited. Insect control will cover a current crop update and uh we'll sew it up after that. What we're trying to do is bring on people on the University of Georgia Pecan team. Here's somebody that we get to travel the winter doing our winter meetings, and is on the team through the Department of Entomology. It is Dr. Aperba Barman. Aperba, I want to welcome you to the show.

SPEAKER_00 1:40

Thank you, Andrew, and thank you, Lenny. Uh it's been a pleasure working with the Pecan team for the last three, four years. So I'm excited to share the information and also get your feedback. So looking forward to the discussion. Hopefully, uh some of the information we relay to you today will be helpful in managing pican insect pest or other operations. It's close to four years. So I started uh August 2022. So I got to see at least three full seasons. This is my fourth season. So yeah, learning along the way. I did not have a pecan background to start with, but uh, you know, as an entomologist working with the insects on different cropping systems, uh I feel like I'm getting to know the insect pests uh and understanding their biology, what they do. So yeah, um I feel more comfortable today than when I started back four years ago.

SPEAKER_03 2:48

Well, you mentioned biology. We're definitely going to talk about biology today. Aperba, you're there are so many insects in the Pecan orchard, and you have to definitely uh you dial in on a number of them that are our greatest pests, but there's still a lot of insects that we probably call secondary. They're not a problem in every orchard, and that's kind of that can take the conversation to a whole nother direction. So today, I definitely want to hone in on pecan nut case bear, and that's what's on growers' minds right now. Before we jump into it, Lenny, I did want to ask you, maybe we could all cover a little crop update. What are we seeing in the pecan belt, especially on your side?

SPEAKER_01 3:31

Yeah, it looks like we're kind of getting toward the end of pollination. So we're starting to see flowers that are pollinated. You see the the stigma's kind of drying up and and turning dark in some cases. But still, overall, it's still looking pretty good. We've we finally got a rain a couple days ago, and that's certainly going to help help things because it was terribly dry. But so far, you know, everything's looking looking pretty good. Uh again, the scab pressure has not been too much. Uh, we've we were dry for so long, then got that rain. I think most growers still had on a spray or two at this point, so that's that was probably adequate for what what they had, and uh so far everything's looking good.

SPEAKER_03 4:14

In East Georgia, I would say probably 80% of the growers have had one spray on before the rain. We've come out with an inch, a little bit more than an inch of rain this weekend. And there's probably 20 or so percent that had not had a spray before the rain. And I'm I mean, most of them probably sprayed right ahead of it as we really promoted that. Anybody that talked to us during the week, I'm kind of happy to hear or at least see some of the flowers that I've seen out there. And um, we're doing a low input fungicide program trial on Excel. And so I've been particularly looking at some of those in in a few parts of the state, but everywhere we're doing the low input, the county agents that are working with us say, yeah, I'm finding flowers on them, and that way we can get the spray on the flower. But at this point, it doesn't guarantee that they're gonna hold them. And we definitely saw that last year. Um, but there's other varieties that people said they like the flowers they see. So our biggest question though, and we get to go back to a purba now. Our biggest question is what about the pecan nut case bear? Aperba this week. This is the question. When should we spray for pecan nut case bear?

SPEAKER_00 5:25

Sure, sure. So uh pecan nut case bear, it's uh in a moth pest. So the adult moths, this pecan nut case bear is what we call technically their specialist insect, so they only feed on pecan, no other crops. So they are always in the pecan orchards, uh, and every spring they emerge, and this moths uh they lay eggs, and it's very interesting how this coincides in nature. So these moths, you know, they develop and they mate, male and female, they mate, and they lay eggs, and their egg laying coincides with this young nutlets. So for the last you know, few days, I have been checking these nutlets every day, going to our ponder farm and looking at them, and we just started to see some eggs. So it's very interesting how you know their egg laying correlates with the nut development. So this picanut case bear, these moths, they emerge in the spring and they made and they start to lay eggs. And these eggs are eventually going to hatch in four to five days, and the little caterpillar come out of the eggs, they would start nibbling on the young nutlets, and eventually they will get enter into the nutlets, and that's how they feed on different in a number of nutlets, because this time kind of you have four or five nutlets in a cluster, and they can damage all the four or five nutlets, and they will those nutlets will drop. So that's the typical damage of pecanut case barrier. But these insects are going to stay in the orchard, and they might also feed on larger nuts, but that time nuts are much bigger, they will probably damage one or two nuts, and those are insignificant. But this time of the year when nuts are small, uh, that's when we see the most damage. That's why we say the first generation of PNC is more damaging than the other generation. And again, you know, uh, this there will be you know three to four or could be five generations uh of this moth in in pecan orchards. And historically, what we have seen that the pressure of this insect population, pecan nut case barrier, is more on the western uh states. So if you go to Texas, New Mexico, you know, they uh typically experience more pressure from uh pecan nut case barrier than on the eastern side. Uh here in Georgia, it's very interesting. Uh, you know, we at least uh in my program, we have uh started to monitor the pecan nut case barrier population in the last uh three, four years. And we see we capture a lot of mods, but uh our growers or even all the research scientists here in UGA or in USDA, we see that typically we do not see that damage. Although we capture you know a good number of mods and we expect to see higher damage, in reality, we do not see a lot of damage that does not sometimes correlate with the number of mods that we capture. And it's very interesting why we do not see, and one of the hypotheses, it's still a hypothesis, we have not kind of really tested this in the field, but we have observed that there are a number of predators, you know, there are minute pirate bugs and there are some myriads. Um, these are you know called plant bugs, but they are predatory in nature. And Ted Cottrell mentioned this, and I started to observe this year. You know, I'm looking at this more closely. We see a number of these predators, and if those predators can feed or predate on this PNC, can that case bearer eggs that might lower the overall population? So, although we may have a lot of moths, but in reality, the actual population or the larval population may be less because of this predation. So, this is something we are gonna try testing this in the lab and also observe in the field. Nonetheless, you know, we have moths and we see eggs. So, in some years, I have seen quite a bit of damage. For example, last year we saw, you know, a good 10-15% not infestation in desirable, for example. And we do not have any kind of documentation about which variety has, you know, which variety is more susceptible to case barrier versus other. But that is something topic of research in coming years.

SPEAKER_03 10:37

Something very important that really came out of that or purpose that I was going to get to is, you know, and this is something that y'all have taught me since I've been a part of the team, but but I've heard y'all talk about Dr. Ted Cotrell's talked about this, that in all the trapping that goes on this time of the year, and that that trapping is to determine what we call the biofix. This is what will establish the mating and ultimately laying of the eggs. That's what establishes the timing of our application to control them. But you mentioned this the trap captures don't always correlate with the damage, which makes the management of this more complex. But your point is we don't know why, but it's just sometimes we catch a lot in the traps and we think, oh wow, this is going to be a big year, and then we have almost no damage. It is possible that this is because of predator bugs that might be feeding on the case bear eggs once they lay those eggs on the nutlet. I remember in 2020, now this I remember this because I had first started, the state had 70, it was really more like 80 and 90 percent of a crop. And when I say 90%, what I mean is at the end of the branches, what we call the terminals, just about every terminal had a nut set on it through Georgia. And we recommended that everybody lay low on pecan nut case bear because we were hoping to get that thinning, that they would actually feed on the nut, that nut would drop and then it would thin that crop because that tree is going to have trouble. It's not gonna fully make a 90% crop very well. But what we noticed, especially where I'm at and growers who followed the case bear, we had very little damage to case bear that year. It was like they had all the nuts they could feed on and then virtually none. And many growers that weren't used to fruit then, and they came out that year and fruit then, they said, we have no choice, we've got to eliminate some of these. That's probably the most difficult thing to manage with the case bear. So should we worry about pecan nut case bear with a high crop set or maybe a low crop set?

SPEAKER_00 13:03

I would worry when you know we are kind of on the low year, off-year. So that's when you don't want to lose too many nuts. But if we are on year, we have you know the tree is loaded with nuts, then obviously you can lose some nuts uh from pecan nut case barrier. And those nuts are probably some of those nuts will drop eventually, you know, kind of in the mid-season, anyway. And again, you know, the insect itself is you know complicated, it's a biological system. Nobody can really tell what's gonna happen, but we are dependent primarily on this moth capture. We have the tool to monitor their population when they emerge. And uh you know, we mentioned about this biofix. So every year we put out this trap to capture moths, and when we start to capture moths for two consecutive days in a row, that's when the first day is called the biofix day. And this biofix, you know, this whole uh system was developed based on a lot of field observations uh out in West. And very interestingly, this year at our ponder farm, we hit the biofix on April 18th. And since then, I kept going to the orchard uh and looked at the nutlets, and I never found eggs until 28th of April. So, according to the you know the literature or the biofix, uh this whole you know system, we should expect this egg uh after 10 days after we hit the biofix. And it was very surprising that exactly on the 10th day, I was able to find eggs on the nutlet. So I think this uh observation or this biofix is you know very solid. It provides uh at least this information that when you see this moths on the traps, you should expect egg laying after 10 days or so. And these eggs are going to hatch in four or five days. And that will give you a kind of idea when you should expect this damage of pecanut case bear on the nutlets. So if you feel like you need to make an application, then you need to make that application between that 10 to 14 days from the biofix date. And this biofix date may slightly vary from location to location. For example, here in the southern part, maybe a little earlier, maybe if you go to a little north, could be a little later. So I think there is a value to have these traps uh in our pecan orchards and monitor you know when you see this pecan nut case bear. And whether you decide to spray or you know, you don't want to spray, it's up to you, or it's depending on the crop. Every year the scenario could be different, but at least this trap is going to provide that information when to make an application in case you want to make an application.

SPEAKER_01 16:25

What are they kind of looking for in those traps? So I know I remember it used to be that growers would be told, okay, you if you're trapping, you're kind of monitoring those traps, counting the moths in there every week or a couple times a week, or whatever. And when you see a peak in the moth trap catches, and then it kind of drops down, that that's kind of your sign that the biofix is taking place.

SPEAKER_00 16:57

Is that what is that accurate or is that it's it's not you know technically accurate. I think a lot of growers um and our crop consultants, they go with their experience, I mean what they have seen. And I personally give more credit to experience than the actual you know one data point. But you know, the insect emergence, if you think, you know, the emergency usually happens like there are few, you know, early on. It's I think it's very common in biological system you have this bell-shaped curve. So you have fewer early on, then there's a peak, and then again it'll start and drop. Uh so the biofix is based on you know the initial caps, but after that initial caps, you likely to see higher capture you know in the next couple of days, and then again it will start dropping from that point. Again, there are not a kind of solid number when you know what triggers the application, but you know, in our experience uh this year, for example, at our Poner firm, when we had this trap, we started to capture on an average 10 moths per day. So that tells me there is you know a good amount of moths. But in some traps, there are very few moths. So, you know, if you compare these two scenarios, then yeah, I would tempt I would be tempted, you know, tempted to apply or make an application if I have higher capture. You know, I was recently on a call with my colleagues uh out in New Mexico, and they say that you know there is a consultant, I mean he goes by 20 20 mods. I mean, when he sees 20 mods on his trap, I mean that's when he kind of triggers his application. So again, if you you know see fewer mods, I mean that should not alarm you, but if you started to see at least 10 mods on an average per day for a week period, yes, I think you have a sizable population.

SPEAKER_01 19:05

We use the term biofix. Can you explain exactly what what that is?

SPEAKER_00 19:11

So uh the biofix, you know, uh most of the insects they have this uh degree day model. So the degree day model is you know, the insects their development is uh very much dependent on the temperature. Every time, every day, whatever kind of degree day or the temperature they accumulate, it goes into their biology. So, for example, insects from starting from egg to get to the first insta or the first you know stage of the larvae and to the second stage of the larvae, every insect needs a certain amount of temperature, what we call that degree day. For example, if you have temperature over six, you know, let's say today your daily average is 70 degrees, and in that kind of threshold is 60, so you accumulate 10 degree days, you know, one day. So if there is uh insect that needs 100 degree days to go from one stage to another stage, so that insect would need you know 10 days of you know this temperature, like 10 degree days over that period. So again, this biofix is that's kind of the start of the clock. As soon as we capture this moth, we call this biofix because we expect that after the 10 days, they are going to lay eggs. So once they start to lay eggs, you know, we know the biology of the insect. So the egg needs about four to five days to hatch. So now we know that uh when you have, for example, uh 15th of uh April, you have the biofix. Then after 10 days, that is 25th of April, you expect to see the eggs. On 30th of April, you expect to see the larvae, and these larvae are going to feed on the nuts. So again, the biofix is one of those timelines where basically it starts the clock.

SPEAKER_01 21:11

I'm gonna go back in time here a little bit because like when I first I think it's I think pecan nut case bearer management has changed tremendously just in the 20-something years that I've been here. Uh, I've seen it change a lot. Like when I first came on, of course, Dr. Dutcher was our research entomologist for pecans, and uh Will Hudson, Dr. Will Hudson was our extension entomologist for pecans. And they worked really hard to try to develop some of this data and information that you're that you're talking about here and discussing. And I think with some of the newer insecticides that we've got now, I think it fits the system. Those materials fit this system, or maybe they help to make this system more more manageable. Um, because I know back then. There were still a lot of growers using, say, like Lores Band for case bear management or case bear control. And then of course Lores Band is a broad spectrum insecticide. So it's not just killing the pest, it's killing everything that's out there. And we've gotten a thankfully, we've gotten growers away from that, away from using those broad spectrum insecticides early in the season, especially. And now pretty much, you know, Lores Band is I don't think you can use it now. I think it's not labeled anymore. Some of the pyrethroids, you know, are broad spectrum and they are still labeled, but growers have have learned to not use those materials early in the season because it does disrupt all those beneficial insects and predators that you mentioned and parasitoids and things like that that help us with control of these pests. And by being able to get rid of those broad spectrum insecticides early in the season, it's allowed us to rely more on them, on those beneficial insects. And then also the chemistries that we have now for controlling pecan that case bearer are more targeted, I think, and more specific. Could you touch on that for a minute? I think that plays back into kind of what you you're saying with the with the timing of and I think that's the key, and it is for so many things in growing pecans, timing is the key to the whole thing. So could you touch on how those materials, those chemistries that we use now, why timing is so important for that?

SPEAKER_00 23:40

Yeah, that's a great point, Lenny. Uh I think, yeah, over time I think we are using different chemistries than what we used 10, 15, 20 years ago. And like I said, these uh predatory insects, they play a significant role in reducing the pest population, especially on the pecanot cage barrier. If it is true that we have you know less pressure of pecanut cage barrier because of the predatory bugs, I mean that is significant. Beneficial insects are playing a really significant role. And using some of these broad spectrum insecticides, we use uh large ven or sometimes when you know pyretroid, even sometimes dimolin, you know, dimolin is also a kind of more of a broad spectrum. These uh broad spectrum insecticides, when we use, we take out not only the pests, also the beneficial insects. And these beneficial insects, you you know, these are kind of our friends. So if we kind of take out the you know the those beneficial insects, you know, they uh you know there are some other pests, for example, you know, you'll have aphids coming in later on. So early on, if you take out this whole beneficial insect population, then your pest population subsequently are going to be worse. But fortunately, you know, the some of the new chemistries, you know, our growers they use intrepid. So the intrepid or intrepid age, this is more specific, you know, those are these are selective to the uh caterpillar pest, and it has uh somewhat longer residual activities. Again, the FMC and you know other companies they have this diamides, they had this pentacore, and now they came up with this uh new branding, Corazin Evo. So corazin is also a kind of lepidopteran material. So these are kind of more selective insecticides, those are highly effective, but only to the caterpillars like pecanutrier or even sharkworm, and they have very minimal effect on the beneficial insects. So you kill the insects but you preserve the beneficial insects, you know, you kill the insect pest, but at the same time preserve the beneficial insects. So you're basically you know kind of boosting the system uh so that we get maximum press uh suppression using the selective insecticides. So using these new chemistries, you know, kind of more sustainable way to manage the pest population, where you are encouraging beneficial insects and having much more efficient uh activity on insect pest population.

SPEAKER_01 26:28

Yeah, and I and I just know uh historically, I mean I've seen it just in the time that I've been here, the change and the chemistries that we use and rely more on those beneficial insects early. I know early on when I first started, and growers were using some of those broad spectrum insecticides early in the season, like we mentioned, the aphid populations would just be through the roof after that. And then all season long they're battling aphids. Um, but now I don't really see, especially yellow aphid populations, you I just rarely ever see them get to a point that they're they're they're damaging. I mean, yeah, you'll see them and you may see some honeydew on the on the leaves, but they don't get to the same levels that they used to when growers were accidentally taking out those uh beneficials trying to control the pests for those broad spectrum insecticides. So I think it's it's changed a lot and it's for the for the better for sure.

SPEAKER_00 27:28

Yeah, sometimes we just kind of underestimate the role of these beneficial insects in our cropping system. And if you can't, it's very unique and you know, like other nut crop uh tree crop, it's more a stable system. So they uh have better success in this perennial tree system, and uh we need to take advantage of the beneficial insects.

SPEAKER_01 27:50

I want your critique of my my approach to to managing uh case bear in the only varieties that I generally spray case bear for are uh pawnee and desirable. I spray it on desirable uh for case bearer because you know, desirable, no matter what how great the crop load looks early in the season, they're always going to drop a lot of nuts in June. And so my thinking there is I just want to be able to preserve you know whatever else I can that Mother Nature doesn't just take by dropping those nuts in June from that natural tendency that they have. And then Pawnee, I feel like the price for pawnee being higher because it's the first nut that we harvest, um, you can justify the expense of that spray on those. But then most of the other varieties, I generally don't worry about spraying, especially in a heavy year. I think it probably probably benefits you to let them thin some of them. But most growers like to have, you know, feel like they are in control of that. So that's understandable. But that's what I that's been my approach to it, and it seems to have worked pretty well. But just uh what's your thoughts on that? And would you have any suggestions to change that in any way?

SPEAKER_00 29:13

No, I think you're right. Again, a lot of this uh pest management, what we talk about is kind of related to the price. Like you mentioned, you know, pony. Yeah, you want to save nuts where you get the most you know money out of it. And see kind of similar experience, you know, other growers may have. And um, I remember one time I met a grower in Cook County, and he said one of his blocks always had higher pressure than other. I mean, again, if you're a grower and you've been growing that crop and year after year, you have kind of more understanding about the insect pressure and what kind of loss you have from the insect damage. And you know, I just don't want to go ahead and say that okay, you need to spray for case barrier all you know on all your blocks and all the varieties. But again, as a grower, if you're trying to, you know, be judicious and be conscious about you know where you're spending your dollar in terms of input and what kind of return you expect, and I mean these recommendations are going to be vary from grower to grower and variety to variety, even block to block. So yeah, I mean, I I don't want to say that you know this is the time to spray for peak and case grader and go ahead and you need to make an application. No, that's that's not true. That's not how pace management or integrated pace management work. I mean, there's uh always an economic component to what we recommend. If it is not economical, don't do it.

SPEAKER_01 30:48

Another thing I want to mention, I think you touched on it a little bit earlier. Uh, because we may have people, you know, a lot of what we're talking about here is for for Georgia, you know, for our case bearer situation here in Georgia. But I think out west, like in Texas, let's say, um the case bearer problem is is much worse than it is here. And my understanding is that out there you have to spray for them. As opposed to here, you kind of have a little more of an option, it seems like. Why is that? Do you know?

SPEAKER_00 31:22

To be honest, I exactly don't know what are the reasons why the pest pressure is higher there. But to me, I think it has something to do with the weather and the kind of survival of the overall population. So, you know, I have seen in the past in the West, in general, if you go to California or even Arizona, you have higher incidence of insect pest versus disease. But if you are here in Georgia or in Alabama or you know, this on the southeast, you have higher disease pressure, the insect pressure. One of the things, you know, over the years, what I have observed that when you are on the eastern side of the country or kind of southeast, you have a kind of complex and more diverse vegetation, you have more kind of heterogeneous um habitat, and that supports your kind of insect diversity and beneficial insects. So, in the past, you know, I have worked on cotton systems in the West, you know, in Texas specifically, you have just cotton patch, you know, miles after miles, and there is hardly anything out there other vegetation. And pests always have a better chance of surviving and causing the damage in absence of these beneficial insects. In order to kind of preserve that beneficial insects or support them to kind of encourage them, you need other habitat. So that's kind of my feeling that we have more beneficial insects like predators and parasitoids here in the southeast that might help suppressing the even not only case barrier, maybe other populations, other insect populations. But in the West, you have very less opportunity for those beneficial insects to kind of perpetuate and kind of augment or you know, uh kind of flourish uh to have a greater impact on the overall insect population. So, yeah, uh recently, like I said, I was talking to Kristen Bauer in New Mexico State. Uh she has been doing some work on pecanut case barrier, and I learned from her that you know their population is really you know significant and they always pray for pecan nut case barrier. And we're you know brainstorming this idea that you know they may have very fewer predators or you know other beneficial insects in the system compared to our southeastern system. So that is something we have been thinking to explore. Uh and in the past, you know, I have not worked on pecan in the Texas area, but you know, I learned from other people that you know they may have even an extra generation. So, you know, they have their much warmer climate, they have you know fewer uh rainfall um events. So all these things may kind of contribute to the higher insect population, kind of lack of beneficial insects and more generation, uh, more opportunity to kind of multiply.

SPEAKER_01 34:38

It makes makes sense. And I don't want to try to minimize that it can certainly be an issue here. Um, I mean I've seen I've seen a couple of times too where they wiped out a a lot of the crop in in an orchard or two, but uh I would say it's much more rare that that happens here than than you would see it out there.

SPEAKER_00 34:58

Yeah, I think you know, although we blame that you know, our what humid uh climate is not good uh for pecan for you know specifically for scab, but with some rainfall and you know this weather, you know, we have some advantage of having these beneficial insects. Even if you think about some other kind of anthropomopogenic fungi, they have a better chance to infect these insects or provide this beneficial service in insect separation than compared to the western states. And you know, one good example is this fungi that infect this uh cotton aphid. So we grow a lot of cotton here, and you know, our growers they don't even spray for cotton aphid. But if you go to west, I mean when I was working in Texas, I mean, cotton aphids, you got to spray. I mean, otherwise it's gonna you know eat up that those tips. But they don't have the advantage of having any fungus killing their aphids because they are so dry. But here in the east, you know, you don't need to spray for cotton aphids. I think some of the kind of similar reasoning can be you know extrapolated, you know, or pecanut case bear, other pest management system.

SPEAKER_01 36:16

Yeah, so a little known fact here. My my PhD is actually in entomology. Yeah, and uh and my uh research for my dissertation was on that that fungus on for cotton. And so we uh you know we had different plots and everything, and some some plots we had sprayed fungicide to eliminate the fungus, yeah, and other plots you know we didn't spray. And we go out and monitor the aphid populations, and of course, the ones where we sprayed fungicides and eliminated that fungus, the aphid populations exploded, and those that we didn't spray where the fungus was actively working, it was able to cause a crash in the aphid population. You know, yeah, so that's all direct direct evidence of that.

SPEAKER_00 37:02

So yeah, I didn't know that, Lenny. It's kind of interesting that I'm speaking in front of an expert who did all this research. But I think you know that is a kind of logical explanation that you know this uh humid weather and you know our environment probably helping us in some ways, uh, some of this pest uh separation.

SPEAKER_03 37:27

Yeah, Perva, you know, that that covers a lot on pecan nut case bear. And you mentioned, well, you gentlemen are talking about aphids right now and cotton, and but probably our number one pest is uh black pecan aphid in in regards to you know the damage it can do with dropping these leaves. It's not something we generally talk about this early, however, what happens when a grower sees adults of black pecan aphid in the orchard early, like in the month of May? This can happen. Can you help us out with this?

SPEAKER_00 38:06

Yes, I mean you will see a kind of yellow spot here and there, even now, because black pecan aphids like pecanut case barrier, you know, they're specialist insect. I mean, they only feed on pecan, they don't have any other hosts to feed on. So these black pecan aphids, they are going to be in orchard and probably you know feeding on some leaves, and you'll see this black uh so the yellow spots on the leaves here and there. But good thing about this uh system that black pecan aphids they cannot reproduce. I mean they can feed a little bit, but uh they cannot really exploit that leaf and uh produce the offspring at this time of the year because this leaf chemistry uh does not support you know their uh biology. And as a result, although we see black beccarna feeds adults at this time of the year, we do not see any names or the immatures uh to a significant level that would you know cause a lot of yellowing and you know this uh the browning and uh what we see kind of late in the season. So, yeah, you'll see black pecan aphids here and there, uh, but you really don't have to worry about black pecan aphids until late in the season, let's say late July, early August. So uh I would not worry about black pecan aphids at this time of the year, uh, although you may see a few here and there. Don't worry about it. Never try to attempt making an application for black pecan aphids.

SPEAKER_01 39:52

I see that a lot. You know, I've seen some already this year, you know, spotting up some leaves here and there. And and I guess we could mention, I don't think we talked about so the when the black aphid feeds, black pecan aphid feeds, uh, it causes these yellow spots on the leaves, and then if they there gets to be enough of them on there, it causes the leaves to to drop off. But you know, like you say, you see them come in this time of year, and most of the time you'll see a little bit of that spotting on those lower leaves, and it's not a big deal. I've always ignored that, and like just as you described, they just seem to go away. Um, yeah, you'll have a little bit of yellow spotting here and there, but it's not really hurting anything. And I think if I understand it right, uh that early population comes in and kind of spots up those leaves a little bit, and don't they reproduce faster on leaves that have already been fed on and have some feeding damage? Is there anything to that? Am I thinking right?

SPEAKER_00 40:53

Yeah, yeah, it's pretty interesting insect in terms of kind of research standpoint that uh the you know the mother they come and cause this yellowing, and when they cause this yellowing, basically they break down the chlorophyll in the cell, and the the babies you know they can feed better or they can utilize that food source if it is yellow rather than uh you know green. So the offspring they feed on this what we call the catabolites of the chlorophyll material. So their food is basically degraded chlorophyll rather than like actual you know green portion of the chlorophyll. So later in the season, as the leaf chemistry changes, you have more and more population. The mother will come and cause this yellowing, and they will lay this, you know, they do not lay eggs that time, they just lay the offspring directly. We call nymphs, and then the nymphs will just kind of feed constantly and they will you know get bigger and they will kind of proliferate and cause more yellowing around the leaf.

SPEAKER_01 42:04

They're always to me, they're like the most challenging insect to manage because they can depending if the conditions are right, they can come in and those populations can explode really fast, like within a couple of days, it seems like sometimes. And uh that's what makes them so challenging, I think. So when so when would you suggest spring? Is there like a number of nymphs that you look for? If you're just seeing the adults, you know, you can kind of ignore them. But if you're seeing nymphs also, so how many nymphs would you consider a threshold or whatever?

SPEAKER_00 42:40

I mean, I have not really seen uh these black pecan aphids um laying nymphs at this time of the year. Uh, maybe they just do not reproduce, or you know, the reproduction is very minimal. But when late in the season, they would lay you know five, ten names altogether in a cluster and they will kind of start feeding. So honestly, I have not seen them laying names at this time of the year, and even if they do, it would be just like maybe one or two, and they would die. I mean, they would not be probably able to make the entire life cycle. So it's something to do with the leaf chemistry because you know, leaf chemistry, as we know, it changes over time in in pecan leaves, and those you know, phytohormones and kind of other biochemical components kind of change over time. So those probably do not support the reproduction or the kind of feeding or survival of the names. Uh so yeah, I think it's uh in terms of number, I don't have a specific number in mind, but uh even if you see one or two, it's probably you don't need to worry about it because those names are probably uh less likely. To complete the generation. But later in the season, if you see even four or five memes in the cluster, I think they are going to just expand over time.

SPEAKER_01 44:11

Yeah. So in that situation, you need to jump on those pretty quick.

SPEAKER_00 44:15

Yes. Yes.

SPEAKER_03 44:17

This topic is really good for scouts and growers who scout. You know, what I hear from this early season black pecan aphid uh adult damage, what I hear in a nutshell is reproduction. So this time of the season, they're just not the leaf doesn't support the reproduction. If they are not reproducing, they cannot build. And that uh supports us not worrying about them this time of the year. They have to build before they can cause the damage that would subsequently lead to the leaf drop. And I think too, y'all, we need to talk about the real more detailed part of the black pecan management as we get on into the summer. We could do one where we hit more details on it with the insecticides and you know the importance of rotation, what makes this pest so difficult to manage.

SPEAKER_01 45:10

Yeah. There's one more thing I'd like to touch on while we got a perva here because uh I have had calls on this this this week. You know, a perva, there's another pest out there that we don't see a lot, but we see evidence of it in especially older orchards. And I think kind of we're starting to right now is kind of the we're hitting the season where they're kind of their activity is kind of at its peak. Um and so you know, you go in a lot of these older orchards and you see the tops of these trees kind of dying back or trees kind of getting weak. You see a lot of crown gall around the base of these trees and a lot of those older orchards like that, uh, when you start seeing that. Sometimes if it's a real sandy soil, you know, it might be nematodes or something like that. But I think more often in these older orchards, a lot of times it's prionis root bore. Yeah. And so how would growers that are seeing something like that in their orchard, what's what's the best course of action on that? Because that's a that's an insect that, you know, it's a big beetle, the larvae are in there tunneling in the root systems for years, you know, destroying those root systems, and the tree kind of gets to a point where the tree can't support them, and that's when you start to see that decline because the root system is being destroyed. But for a pest like that, that's kind of out of sight, hard to get to, I mean, what are the options for dealing with that?

SPEAKER_00 46:39

Yeah, I think, you know, like we said, black pecan aphid is probably the most challenging in, you know, pecan, but that is on the kind of above ground, and this insect is kind of underground, and we don't see and you know, we don't think about this insect, and it it can cause really significant damage to this root system of the older trees, and we don't even know like if they cause any damage to the root system of young trees, because sometimes you know we have the young trees planted in between the older uh trees, and these beetles are kind of underground. And do they feed on these young trees or not?

SPEAKER_01 47:20

I mean, I think we don't have that evidence that uh I saw actually I saw some this week. You know, they had a big old tree there that was dying from them, and they they cut that tree down and they planted a young tree on each side of that stump, and they noticed that one of those young trees just wasn't growing and it was starting to die back. So they dug that up, and I can send you the pictures of this, but um the root, the tap root of that young tree had been fed on and and just tunneled out by by the wow by RM.

SPEAKER_00 47:57

Again, and this is something you know out of sight, out of mind, that's the thing. Uh but uh the good thing, you know, from the research perspective, we are really um starting to work on several aspects for management of prionis. Uh the traditional approach is we do the trapping. We have this uh black panel trap, we have the pheromone lures, we put them out, we capture a lot of beetles. But these beetles, they are actually male beetles. You know, males are not responsible for, I mean, they are responsible for mating, but the females are the ones going to lay egg. And even though you can capture you know 500 beetles in an orchard, that may not be any significant to reduce the population. And uh that's the challenge. If you cannot control the female beetles, you know, which are already matted with male, then the population is not gonna go down. Uh so we need to kind of target those uh female beetles if we can. And one of the ways you know it used to be managed using lore spend on the you know herbicide strip or around the base of the tree, and when these beetles come out of the root zone, you know, they come in contact with the insecticides and they they die. But the absence of lars bend or any of those chemistries uh you know kind of limiting our ability to um control this pest. There's some hope. Uh this year, actually, as we speak, uh we put out a trial uh in Albany. This is all orchards. We have this product. I mean, this is a pheromone, but there's an idea called metting disruption. Uh, and this has been tested and used, implemented in other insect-based systems. Even our peconut case barrier, you know, out in West, Christian Bauer is doing some of this mating disruption uh study. The idea is uh you know, in insect community or insect species, the male and female uh you know they communicate using this pheromone. So female release pheromone, then male will find them and they will mate. So this males they need this, you know, chemical cues coming out of the female. Uh but what happens is when you put a lot of this same chemical, the same pheromone, you create a kind of cloud. And if you kind of create a cloud, like you don't see, you have low visibility in this cloud of pheromones, the males they do not find the female, they are kind of confused. So that's the way you disrupt the mating process. And when you disrupt the mating, that means you know, insects would not have eggs to lay, and that's the way you know people have had success in other crop systems, for example, apple pears and things like that, coddling moth. So this is a proven system uh you can use to control insects without using chemicals. So this is a technique we are trying to use for prionis. So we just collaborated with a company. Some of these pheromone strips came from Japan, and we're we actually put out a lot of these uh pheromone strips in this orchard. And our hope is that uh you know these males are gonna be confused and they won't be able to find find female and disrupt the mating process. I mean, we are not gonna see the immediate effect because this is like a three, four-year kind of life cycle for this insects. So we are not gonna see this immediate you know, uh lower population or so forth. But if we do this uh you know for next three, four years, we should see some significant reduction in population. And if it works, I mean this could be another tool to manage prioness. And in the meantime, we are also looking at some uh uh other chemistries, for example, LD carp, which um you know the Temic they used in a row crop, so it is kind of a good nematicide and also has kind of longer persistence in the soil. So this could be another alternative. We don't have any kind of label product yet. So that is something I've been exploring with other uh manufacturers that can we use other chemistries which are long-lasting on the soil as an alternative to large vent.

SPEAKER_01 52:43

Let me ask you this. I mean, I see like like for other like say turf crops or something where you have a lot of the beel bar that feed and damage damage those. I think they use it a midacle, is it a midocloper that they use a lot of, or I mean what do they use in those crops? And would that do anything for for this?

SPEAKER_00 53:07

If you think about you know the pecan root system versus tarf, you know, our root system is much deeper. So you know, in tarf you have like this heavy irrigation with the kind of chemistry, so it just kind of soaks down the root, and you have um you know better success in controlling the insect. But in pecan root system, you have roots are much deeper, and you really kind of know where to soak it up with some insecticides, and roots are much spread out and kind of deeper down, so that may be a reason that we may not be able to just kind of copy what they do in tarp, but but there are probably some in opportunity to look at some chemistries which may have impact on kind of root system and root feeding insects. Uh, I have not looked at it, but I think that is another um good opportunity to look some of the chemistries that do well on the root-feeding insects.

SPEAKER_01 54:05

Uh great. Yeah, that's exciting about the mating disruption. I hope that's because having a non-chemical option would be great.

SPEAKER_00 54:13

Absolutely. Yeah, no, I we'll we'll talk uh in our future episodes, uh, you know, some of this metting disruption work we have been doing on uh hickory sharkworm. So I think you know this is another tool in our toolbox to manage insect pests and it has some kind of unique opportunities rather than applying insecticides. You can have this metting disruption product that has kind of longer you know residual activities. For example, if you put this out, they may be diffusing this chemical over three months of period, and you have a really you know uh longer period uh to control that insects rather than if you apply an insecticide today, if it rained out, you might have to kind of go back next day to reapply. So another thing maybe we can just mention a little bit about sting bugs. Thank you. You know, share with the growers that if they're seeing sting bugs in the past, that is something they can start to monitor and kind of be more vigilant about it.

SPEAKER_03 55:37

I think I think I would hold that to another one because you know you talked about that at our county meetings, what you're doing with those traps. So that would be uh great when we come back with you, you know, in a mid-season kind of thing.

SPEAKER_01 55:50

Yeah.

SPEAKER_03 55:50

A purpose so far, Lenny and I have done about one a week to get it kicked off. And uh so you're helping continue that. Well, a purpose, I want to just thank you for being on with us today and uh sharing this at least early season insect perspective for this in a nutshell, the PCAM podcast. And I look forward to having you on again. You have other insects you can cover. So, gentlemen, it's been good for episode number four. So look forward to being back on again and seeing what we got next.

SPEAKER_00 56:29

It's been a pleasure. Hopefully, uh, some of this information will be helpful to our listeners.

SPEAKER_01 56:35

Thank you a lot.

SPEAKER_03 56:37

And then we can get tired of hearing just me and Andrew's uh listen to it. Thank you all for listening. Stay tuned for the next episode. You can get more information on the University of Georgia PCM blog in a nutshell, the PCM podcast.