BugBites! Session 5: Effective fungus gnat and shore fly suppression with beneficial organisms

February 9, 2021

Video Transcript

- Good morning, everyone. Welcome to Bug Bites. My name is Jeremy and I am a greenhouse agent with Michigan State University Extension. This is the fifth and final session in a series of short seminars by industry experts speaking on topics suggested specifically by growers right here in Michigan. Before we start, I wanna bring your attention to the Q&A button located at the bottom of the Zoom window, or at the top depending on how that's arranged. Please feel free to submit your questions at any point during the presentation. We will be keeping track of them and I will be sure to give our guests a chance to answer them all at the end of the presentation. Okay, Saul Alba and Greg Bryant are IPM Specialist with Beneficial Insectary. Saul started out working in winery and vineyard operations in Central California. Since then, he has worked as an IPM Manager at mushroom companies. Jacobs Farm/Del Cabo and Harborside Farms, and he is now joining the team at Beneficial Insectary. Greg has a strong educational background in zoology and entomology. He earned his degree from Auburn University in Alabama, and has worked in a variety of roles in crop science research and biological control. Gentlemen, thanks for joining us. Saul, I've never seen it, but I imagine that mushroom farming is very different than the traditional horticultural crops that we see every day. What are the most common pests? - Well, believe it or not, it Sciaridae, the fungus gnat. - No kidding. - Exactly the topic for today. But mainly because they vector a fungal disease. There's a Verticillium that is pretty destructive to mushroom production, and they move it around. So, they are the primary invertebrate pest. - Okay. So, what do you guys have for us today? - Just some topics on fungus gnat and shore fly, biocontrol. My presentation is a little bit more of a primer. It talks a little bit about monitoring, so, I'll try to move through that faster since it looks like your audience is pretty familiar with the pests we're talking about. - Yep, polls are helpful that way, aren't they? - [Saul] Mm-hmm. - All right, I will turn my video off and you can take it away. - All right. Good morning, everyone. Okay, how's that? - Perfect. - All right, brilliant. Yeah, as Jeremy mentioned, I'm the one of the IPM specialists for Beneficial Insectary. We are a producers of parasites and predatory insects and other invertebrates for crop protection located in Northern California. So, if any of you are interested in talking to us about biocontrol agents, are given an email at the end of the presentation. So, just start off we're talking fungus gnat and shore flies, sounds like many of you already familiar with them. So, why is it important to talk about these? Well, both are seen as a nuisance, but they can transmit disease, and visibly degrade plant quality. Shore fly I don't think as much, they're more of a static nuisances, what I understand, but fungus gnat can definitely hurt you. And like I mentioned, in the case of mushroom production, it's a very important pest in that infectious disease, but it can also really slow down growth when the mushrooms are in their primordia. So, as with all biocontrol, it's best to prevent the pests from really infesting the crop using a combination of natural enemies. That's kind of our approach. There are four main ones. I'll talk about a fifth one, Greg will go in depth on two of them. So, I'll deal with three. So, how do we know when we are still in a preventative situation? We're talking about biocontrol, working best in the preventative situation. How do we know? It's a very simple question, but believe it or not, lots of growers don't realize that the answer is monitoring, careful scouting of your crop. And so, what are we monitor with? Well, on the far left there, you'll see what's called the Penn State Fungus Gnat Light. And I think most greenhouse growers aren't familiar with it, basically has a UV bulb and two sticky tapes or wax paper which you spray with a sticky substance like tanglefoot. And as you can see there, I hope you can see it is just loaded with fungus gnat. We would use these both for monitoring and for mass trapping. And it does work for mass trapping, although you need a lot of them. But it's a good way, I think it's something that greenhouse growers should know about. Because there's not a lot of fungus gnat monitoring or trapping going on at night. And this does definitely do a number on them. And then there's a yellow sticky cards that everybody's familiar with. Obviously your loop to be able to see the tiny larva in the soil. And recommend everyone have a dissecting scope as well. This is basically my monitoring tools for fungus gnat primarily but also shore fly. So, it's probably many of you are aware, one of the major reasons why these two flies can become pest in the greenhouse is just uncontrolled algae scum. They both like to lay eggs near it, the larva feed on it. I understand that the shore fly larvae feed exclusively on it. The fungus gnat kind of moves to feeding on algae roots. So, that's a good place to look for fungus gnat and shore fly. So, starting with the Sciaridaes, that's the family for the fungus gnat. Just a little bit of background, which I'm sure you all know. Identifying them is easy when you look at their wing. There's a Y-shaped wing vein there, the arrow points to it. The adults aren't strong fliers, they really like to crawl, they like to crawl around, under any kind of a canopy where it's shady, at least in my experience, they don't spend a lot of time in the sunlight. So, 10 day lifespan for the females, up to 150 oval white eggs, difficult to spot, two to seven days to hatch. As with all insects saw cold blooded animals, it's temperature dependent. Those larva will live for two weeks before they pupate into the adults. Hopefully that wasn't too fast. I like to go over signs and symptoms of pest because that's what we see, if any of you recall the symptoms would be the effect that the pest has on the plant and a sign would be, a sign that the pest is either there or has been there, they're different. In the case of fungus gnat I think you'd have to get a huge population to really see symptoms of yellowing and weakening of the plant. But since we did talk about them vectoring soil borne plant diseases that is just slight injury if your soils infected with any of the soil fungi like in this case for this paint set is rhizoctonia but they can also allow entry into plant roots for any number of other soil fungi, and Verticillium and Fusarium. So, this would be a symptom, although if this is rise up to new direction that was not vectored by a fungicide. So, what are the signs? Obviously the signs are the best way to identify them. The adults in larva adults on yellow sticky cards or as we as I was saying, walking around near the soil mostly under plant canopies. And a lot of us spend most of their time underground, although they will also feed on the tissue that's touching the ground. Another sign of fungus gnat, I'm not sure how many of you are familiar with this scouting method, basically what you see there in that pot is a half of a potato or a slice of a potato. And that draws that draws them up, they can smell it, detect it, taste it, and they will feed on it, very starchy foods, so it's very attractive structure than most roots. So, it's a good way to monitor, I used to use half potatoes, the little mini potatoes to put in very tiny pots. And on occasion, if they were left there a while, they would sprout and we'd have a little plantlet. But in this case with the with the potato slice there probably lasts a while longer. Although when I've done that in the past, they also dry up and then they're useless. So anyway, I think that's commonly known by, this method's commonly known by a lot of people who've battled fungus gnat. Now, on to the Ephydridae family, which is what shore flies belong to. So, the shore flies similar size, I think they're significantly larger and bulkier actually. And they look more like regular housefly, whereas this fungus gnat might resemble a mosquito more, they're just fungus on or just more delicate, the most common shore fly that is a nuisance in the greenhouses. You can identify with these five spots that there are points to five white spots on its on its wings, they do fly, they are good fires, probably has a lot to do with their with their wing structure, also. They do spend time, up in the canopy and down down below. If I don't know about larva feeding on roots, but they will spend time spent most of the development down in the soil, especially if there's algae on that wet soil. So, it's eggs are laid in the in the algae or the wet soil, and they take two three days to hatch. They are semi aquatic. So you might see them in those puddles of algae scum, like the photo I showed earlier. That's a larger magnet. They feed for three to six days there and then emerge as adults. So, this is the sign of the adult shore fly. This is where the real problem is. All those little flies specks are essentially fly vomit, they regurgitate. And obviously if you're growing ornamentals, that is no good. So, that's the reason why you'd wanna control them primarily. Easy way to identify the larva is through their breathing tubes, you can see the little y shaped breathing tubes. And that's because they're kind of they're semi-aquatic. They're laid in a very moist, algae rich environment they may need to breathe and may need to put their little snorkels up. So now on the fungus net, and shore fly natural enemies, like I said, I'm gonna cover three of them. And Greg will talk about the others. So, I'm gonna talk about this invertebrate Dalotia coriaria. I'm sure, you're all aware of the rove beetle, it's predatory soil rove beetle. It is a beetle. Some people think it looks like a earwig or a scorpion. And their larva are also predatory, they're a lot tinier, obviously. They look a little worm-like but they move fast and they're mostly orange. If you look through your soil, if you've got Dalotia coriaria in your growth look to the soil you will often find these as they are readily established in greenhouses. The other really cool thing about the Dalotia is that it is in fact a beetle. And if you look I don't have a pointer I don't think or do I can you see that? I don't know that there is are the elytra which are the top wings down below underneath them is all their actual flying wings folded carefully. And this is a cool photo of Dalotia getting ready to take off in flight. It's actually a great feature of this predator in that it can move around, it readily moves around the greenhouse. And it can fly from bench top to the floor of the greenhouse and vice versa back and forth. So you will, at times even see them up in the canopy. Some of you may be aware of these Dalotia rearing boxes, we've got instructions if anybody's interested in trying these are basically what they are as little breeder colonies that you can set up yourself, some growers I've seen put them under benches. They're just a media, some kind of a media like a peat moss media, vermiculite in it, that's kept moist. And in this Tupperware cage, or whatever you'd wanna use, with, obviously, some screening to keep them from leaving before it's time. And obviously that that's greetings permeable. And then as a food source, you can use anything dog food, fish food, I've used, I've even used artemia, what they call the brine shrimp eggs, they like those. They're pretty omnivorous, they eat anything they can find the larva-like, all this feed to the larval will feed on it and then develop, basically, you rear them up. And at a certain time when you've got a population of adults, you allow them a means of escape from, from the breeder box. And so they're just kinda like, just a slow release type of approach for these. Like I said, this predator will readily establish in greenhouses, this is just a way to keep your populations up. And then just as an aside, I've been playing around with live food for the ease springtails. And most crops, I don't think are a real big problem. So, I've been trying to rear colonies of springtails and see how well, how fast Dalotia develop, if they don't develop any faster than with the fish food or whatever else you use. And anyway, more to come on that I guess if it ever turns into anything. Let's see. So, this particular farm or a greenhouse, actually got the Dalotia to establish in their growth. If you look, I'm not sure if you can see that photo. This is kind of basically when biocontrol wins, right? The green circles are actually the Dalotia that flew and got stuck onto the yellow sticky cards and there were only two flies. It was one of the cleanest under canopies I've ever seen. All right, on to the next natural enemy. This would be Bacillus thuringiensis israeliensis bacteria. Specific for diptera for flies. It's essentially a stomach toxin but doesn't exactly work like a like a toxin. But the bacillus will enter the fly for through feeding and then recover in their gut. It is not effective against shore fly. I think the reason being primarily because shore fly is not feeding on roots and in the soil, they can I mean it makes sense to me that they're more like algae feeder. I've always wondered if you could use BTI against shore fly by spraying the algal mats, if you know what I mean. Like lots of greenhouses have a hard time controlling humidity and their floors and you'll see growth of algae if you spray those with BTI but I don't think that's on the label. So, but just an idea, I wonder. If the BTI is either drenched in or chemigation, the soil drench is the best technique, basically it covers every square inch of the surface where they may be. I'm not so keen on the drip, spaghetti drip lines. Like the one there in the middle. Just because you have to get the so really wet. How much of the BTI get centrally filtered out? I don't know. But if you had a little micro irrigator, like little micro sprinkler like the one on the far right, that can help. I don't know how many of you all use those? And what about the ultimate pathogens, this would be an interesting approach. I do have one customer in Florida, who controls fungus gnat with Beauveria bassiana. She's actually claimed she's seen the dead infected, covered with with her hyphy in the soil. But it's not typically used for that. And if you read the labels for the ultimate pathogens for all those products that are commercially available, fungus that isn't listed on there. However, just awful is fruit flies are there's no reason why it can't. It might be a infect the fungus gnat. Of interest down there, at the at the bottom of the slide, found a paper by Stangalini that came out in '05, where they actually found a shore fly. That shore fly cadaver that was covered with Bavaria. They cultured it on millet and then spread the millet on the surface of their their pots. And sure enough, it helped to control it. They were they saw more, white fuzz covered adults. So, it can work. I would imagine that there's nothing I think that's registered for them. That's it for me. That's my contact info down there. Obviously, Jeremy can give you that if you want or any other, phone number, whatever. Just send an email and I can I'll reach out. Thank you. - All right, sounds good. All right, so let's all set I'm gonna talk about two different biocontrol agents used to combat either fungus gnats or shore flies or both. The first one we're gonna talk about is Stratiolaelaps scimitus. You guys may know them better as Hypoaspis miles, that's what they used to be called. That's actually what a lot of biocontrol companies still call them. But their actual name is Stratiolaelaps scimitus. So that's what we refer to them as they do live in the top half inch of soil. So I do have growers sometimes ask if they can sort of incorporate them into their soil before they put the plants up and not so much you wanna put them on top of the soil. So, they can just kind of go to the level that they wanna be at. Like most mites they've got five developmental stages. You've got an egg, a larval stage, two nympho stages, and then they molt into a reproductive adult. Newly hatched larvae, they're absolutely tiny, like you're most likely not ever gonna find them. But just so they are very lightly colored. They only have six legs, and they don't feed at all, after just over a day, they'll molt into the first nympho stage. And at that point, they'll have eight legs from then until they're adults. And then they'll also be predatory from their first nympho stage on them. I don't know why that automatically went but I'll go back. They do develop temperatures are for about 59 to 86. So, good for most greenhouse conditions. optimum for them is around 77 though, at those optimal temperatures, females lay two maybe three eggs per day. And then those eggs hatch and just two or three days after that. Like most arthropods and cold blooded animals in general, like Saul said, their development time is very very temperature dependent. But for Stratiolaelaps specifically, it is very temperature dependent. They can go from egg to adult and as little as 10 days but it can take up to 46 days for them to fully mature. As one experiment showed that if there is food available, they can live for about 142 days, which is a crazy long time, especially for something smaller than mite. And then that same study showed that even without food has kinda wordy so I apologize but even without food adults can live for 24 days. If they're fed for six days before that food is gone, females live for 65 days and males for about 45. But the shortened version of that is they're very persistent. So, good for long term protection. So, you'll mostly be seeing the adults since they're bigger and just more easily found. So, this is what they look like. They're generally around a half a millimeter long. seen some sources say that they're up to about 0.8 millimeters, but pretty sure they average about 0.5. They do kinda darken up as they get older. So they are like a dark tan, maybe even a light brown color. They are oval, but they're a little more round at the back end and a little more tapered towards the front. If you see the cursor, they've got all these little small seedy little hairs coming off of them. I'm sure you guys know how to use Stratiolaelaps, but they are mainly used for the prevention and to a lesser extent, the treatment effect is nice, but you really do wanna start early. They are like most biocontrol like 99% prevention. They really only the fungus, not larvae, not so much the eggs and like probably don't need to pupate at all. I got i don't think that there's really any evidence that they will. But I still good, good first line of defense for fungus gnats. And like I said, that longevity makes them really good for season long protection. But definitely start early like before you get the fungus gnats established. Great for prevention. And really, they're just a basic part of pretty much all biocontrol programs, in my opinion, like everybody that I set up a program for will get these guys. You can mix them with the Dalotia, they generally play nicely together, they will sort of eat each other if they're in the same space for too long. But so if you do mix them prior to introduction, just prior to introduction. But once they're in the crop, they're in the soil they have room to get away from each other, they're generally fine. Believe that there is some evidence that if you put little breeder piles of Dalotia on top of the soil, that's when you start to get in trouble with them really eat each other. But if you're spreading everybody out pretty evenly, then it should be fine. And then just note that, from what I've seen, they don't really do well in rockwool. So, anybody that may be a hydroponic grower, maybe stay away from these guys and use those Dalotia breeding kits like Saul was talking about. Because I've seen a lot of success with the Dalotia breeding kits in hydroponics. Very underrated in the fact that starting on the left has on biocontrol programs, they also thrips that are pupating in the soil. There was one study done that showed that just by using Stratiolaelaps, they reduce the thrips population by about 43%. I don't know how common that is in real life situations. But I do know that breaking that pupal stage of the lifecycle it is extraordinarily helpful for managing threats. So don't underrate them in that regard. That's really all I had for Stratiolaelaps, it was pretty much just a straightforward species just very long lived and a good part of all optical programs. So, now we'll talk about nematodes. And this is just about nematodes in general. They're in the phylum Nematoda, so seemed appropriate. They are incredibly diverse. Like you can find them pretty much everywhere on Earth. Everywhere from in deep dark caves, like thousands of feet down below the earth. You can find them in mountains, marine environments, freshwater environments, they're just literally everywhere, tundra like everywhere. I've seen an estimate that said that there's probably about a million species, but that was likely a gross over estimate. The more reliable sources that I've seen say that there's about 40,000 species, at least, but that's still a whole lot. Just a fun fact that I read. For every person on earth, there is about 60 billion nematodes just living in top soil. So, incredibly diverse, incredibly prevalent, just kind of everywhere. There are lots of them that are parasitic on vertebrate animals, including us. Some are plant pests. So, things like root-knot nematodes, leading cyst nematodes, reniform, things like that. But then there even others that are useful for biocontrols, so the entomopathogenic nematodes. So, entomo just means insects. Pathogenic disease causing and that's because of the symbiotic bacteria that they have in their guts, which I'll talk more about that. There are lots of species of entomopathogenic nematodes, but the two most studied genera are Steinernema and Heterorhabditis. Different genera of nematodes. They have their own genera of bacteria associated with them. So, Xenorhabdus for Steinernema, and photorhabdus for Heterorhabditis, difficult word for me to say, Heterorhabditis. So, how does nematodes actually work? So, when you get in nematodes, the ones that you buy, they are what's called the infective juvenile stage and their infective with that bacteria that I was talking about. Also called the J2 stage because they have different life stages, just like insects do. So, they're the ones that you get for deleting the ones are J2's or like I said, the infected juvenile once they find a host, so be it a fungus gnat larva, shore fly larva, thrips diva, what have you. They'll enter the host just through any natural opening they can find. Or if sometimes, if there's a thin spot and the cuticle notice bust right on through it, and then everything in this yellow part of the picture that is happening inside the larva, or the insect host. So, once they get inside, they've released that bacteria that they had. And then that is actually what causes the insect to die. So, that bacteria is toxic to the insect. So, they molt a few more times, and then eventually they will become a reproductive adult, lay some eggs of the interaction of juveniles. And then this actually happens for about a week. So you'll get multiple generations within the same insect, oh, and I've recommended that the insect dies from that bacteria and maybe a day or two, so it doesn't take long at all. And then all the while this whole process is happening. So laying eggs, juveniles, adults, and then that goes on for about a week or just whenever the nutrients that are that the nematodes are getting from this insect. When those nutrients are completed, you get more immature, in fact, the juveniles coming out. So, the big stage again, they come out of the insect and these are actually more adapted to life outside the host. So, something triggers that that action happening where they will go from just a regular old J2's that are just happily living inside the insect cadaver and then once once that starts to degrade, they'll get some J2's or infective juveniles that are adapted to life outside, they'll leave and then they'll start the whole process again and find a new host. So, forging strategies really vary from species to species with the nematodes. Some are cruiser species that actively search through the soil. They live tend to live pretty far deep down below the surface, they're mainly going after a sedentary pest. So, the HP nematodes that you may be familiar with, they're an example of a cruiser species, not really talking about them, since we're mainly talking about fungus gnats and shore flies. And those are used more for like grubs and different beetle larvae. Others are sit and wait for ambush predators. And they tend to live on the soil surface and they wait for prey to pass by. So for example, Steinernema carpocapsae which we'll go into a bit in just a minute. And then something a little bit of both strategies and they tend to prefer to live just below the soil surface. So, Steinernema feltiae is an example of that strategy. So the two entomopathogenic nematodes that I'm gonna really talk about are Steinernema feltiae and Steinernema carpocapsae. Oh, that's sort of the video that was gonna show that later. So, feltiae are somewhere in between a cruiser species and an ambush. They kind of have both qualities. When you use them as a drench, They're mainly going after fungus gnats and shore flies. But they will also infect thrips pupae. So, useful for threats control as well. And they'll go after other things too. But what they're mainly used for, like I said, fungus gnat, shore fly, thrips pupae. Certain beetle larvae, they'll go after certain caterpillars as well. So, they do have uses other than this, but since we're focusing mainly on fungus gnats and shore flies, that's what I'm talking about. Again, they like to forage in the top layer of soil only about an inch or two down. So, when you apply them, you wanna lightly water them. So, don't do a full on irrigation because you'll get them too far down into the soil and they won't be happy. They're not as mobile as HP nematodes. They can move around a bit, but if you give them too far down, they may not ever be able to figure out their way to get back up. So, they'll either die or just not find the right pest. So, you really do wanna get them in that sweet spot like right an inch or two down in the soil level. Their optimal soil temperature is from 50 to 78 degrees. So, that should be good for most greenhouse conditions. Use caution, if you do apply them to rockwool, they are a bit susceptible to being washed away. Because they are, like I said, they're not quite a cruiser species, but they're not quite an ambush species either. So, they don't hold on to things that well. So, in rockwool, there's just not a whole lot for them to grip onto. So, if you do apply them in rockwool, do it at the end of the day, when they're when those plants aren't gonna be irrigated again, until the next day, and then hopefully, that'll give them time to do their work before they potentially get washed out. So, starting on carpocapsae. They are a pure ambush predator. And if you see the cursor here, that's the little nematode right there. The host on shore flies, thrips pupae as well, and then many others. They're kind of the one that I like to use when somebody just has some random beetle larva that they really don't even know what it is at the time and just throw some se at it and see if it works. They do not host on fungus gnats. So, keep that in mind too. If you only have fungus gnats, don't use SE, use SF nematodes, there's a diagram of both here. They're very good at finding mobile pests. And that's one of the differences between the cruiser species and ambush species. The cruiser species like to actively hunt and go find their pest or their hosts. So, anything sedentary, they're gonna be all over it. The ambush predators, they like stuff to crawl past them. Because once they post up on the spot, they're really not gonna move all that much at all. So, they're very good at finding both pests. And these guys have no problem on rockwool. They're very good at gripping things. And yeah, so like I said, they live on a solid surface. So, when you're applying them, use as little water volume as possible. That's because you want them to stay on the surface, like you don't want them to get below there at all. And then oftentimes, you can see them with a hand lens, just sort of nictating, that's where that motion is called. And then finally show show the video right now. And like I said, like I've actually seen them doing this with a hand lens, and it's pretty cool to watch. So, they just kind of sort of stand on their tail, and then they wave their face around, and then they're just waiting for something to crawl by. And then once they do find something to host on, what they do, let me back this up a little bit, what they do is they bring their face around towards their tail and say whatever they were wanting to host on is right here. They bring their face around their tail and just fling themselves at it like a slingshot. I couldn't find a video of it of that particular motion, unfortunately, but it's kind of cool to see if you ever have an opportunity. Optimal temps for them are 57 to 84. But since they live on this little surface, the air temperature must also be facted in. Something else you can do with nematodes. You can dip young plants in a mixture of Botanigard, RootShield Plus and nematodes. Of course, if you're using these at a dip, you only wanna use the WP formulations, as the least harsh on your plants. And you can either dip trays, so I've seen, I have a grower in New Jersey, actually that built these tables. You definitely don't have to go this fancy with it. But if you wanna hear it's always an option. What he does is he puts this whole thing, just sort of on top of a bigger table or a cart. So, it's less work on his back, he fills this tub up with the Botanigard, RootShield Plus and nematodes He gets one tray and it puts it on the table right there with these little blockers that don't let the tray fall back down. So, all of that mixture is just falling back. So, he's not wasting as much of it. He dips one puts it there, dips the other, puts it on the right side. And then by the time he dips this one, that was done draining, he puts that on a cart and just sort of does that process over and over again until he's done. And if anybody doesn't do this, but would like to, I've got the rates of everything that growers typically use. So, just email me and I will be glad to give you that information. So, that was for root cuttings and trays. You can even do your seeds. I've seen people use like mesh baskets like this, colanders just whatever you have that that may work, but you RCS and the colander or the basket, dump them down and then what I've seen is people taking like a similar sized bowl and turning that upside down so that everything doesn't float away once you're putting that in the water if that makes sense. But that goes a long way to starting you as clean as you possibly can be. Because that's gonna get, that's gonna protect you from root diseases with the RootShield, the Botanigard is kill things, that nematodes will also infest things. So, really, really good way to start your plants out as clean as you can. Another use for entomopathogenic nematodes, you can spray them on the foliage to help with thrips control. I don't see this all that often. But it but it definitely has been done. This is actually a picture of an adult thrips with Steinernema feltiae J2's exiting it. So, the nematodes aren't picky about what life stage of thrips they're going after, if they can find a way and they'll do it. But if you do appliances and foliage, you've got to be sure to keep those moisture levels up. Because nematodes really require water pathway to go through. And if you do this, I would recommend using Steinernema feltiae, since they're a little bit more mobile. But I've seen people use a mixture of , SF and SC. So to keep those moisture levels up, apply it on an overcast day, preferably so that things don't all evaporate away. And then a lot of people will go back through about half an hour, maybe 45 minutes after spraying them with those on the foliage and go through with like a very, very light mist of water, like don't spray it at all, but you don't wanna wash those nematodes off but just a very fine mist. Obviously Be careful with fungus and other pathogens by having all that moisture on the plants. But some growers have done this and it's worked pretty well. So be sure to QC the nematodes when you get done to make sure that they're alive. If they're S-shaped and wiggly and curly there should be alive and well. If they are stick straight like this, they are dead and not viable. So, what you wanna do is you wanna put a small amount in a dish with a dark background. And the dark background helps helps even better, then you should be able to just take a hand lens and see them either wiggling or stick straight. And you can do this before and after spring. If you do it before spraying, get a general count, like take a known volume of water doesn't take much milliliters really, and count generally how many nematodes you have in there. And then after spraying, do that again. And if you have a big reduction of how many nematodes you're finding, that means that either you've got filters in there, that that's clogging the nematodes up and you're not getting as many out or just something is going haywire. So, always a good idea to GC, pretty much every biocontrol agent that you're getting, including nematodes. Just sort of wrap them up, I've got a complex but fascinating life cycles, fascinating to me anyway, I hope you guys agree. They all have different foraging strategies, just depends on that work against different pests. And then I like to use nematodes as just a quick knock down and soil pests. So, obviously not gonna be super long term production, they will. So, starting feltiae in particular will overwinter. So, they will go deeper down into the soil to avoid frost. But generally just use these as, like I said, just a very, very quick knockdown soil pest and then you rely more on the Stratiolaelaps and to the Dalotia for like long term protection. Like I said, many growers do use them as a dip alongside Botanic Garden, plus foliar sprays as well. But you got to do some extra steps. And then QC then just to make sure that everybody is alive and happy. I've addressed my photo links and citations, and I'm done. - Awesome. Thanks, Greg, really appreciate it. Okay. Before we get into the Q&A, I've got a little bit of housekeeping to do. So, this session is being recorded and will be available. Sometime in the very near future, we will send out an email with a video link to all of the registered participants when it becomes available. Second, your feedback is very important to us. And it is what helps guide our effort to developing interesting and relevant programs for the benefit of the floor culture and greenhouse industries. So, when you leave the seminar today, you will be automatically directed to a two minute survey. The survey today is actually a little shorter than usual. So, that's a bonus. It doesn't take much time at all. And I assure you that the results are really quite meaningful to both us and our guest speakers. And we sincerely appreciate you spending a few moments to share your thoughts with us. All right, guys. We don't have a ton of questions, but we have a few. Are you ready to go? - [Saul] Sure. - All right, so Saul, someone asked a question about potato. So, Tillman asked questions, potatoes are for scouting are pre-cooked or not? Is there a certain risk of eventually transmitting soil borne pests, such as Phytophthora, Verticillium, Erwinia, and whatever. I don't think anybody saw that response. So, I was wondering if-- - Yeah, I just noticed I answered privately I was trying to change it. But it doesn't allow you once you've answered privately, so maybe you can pay copy and paste or I can just go into it? - Why don't you talk about it? - All right, I'm really very good question, one that I've never had come up before. - I've never heard it either - Yeah, it's it's a really good one. I guess what I'd say is, I don't believe that Verticillium and Phytophthora. I think that those two diseases require entry into vascular tissue, which tubers are not those are storage tissue. But Erwinia, I'm pretty sure it can, actually destroy the potato. The question would be, what's the route of entry for any of these? If any of these require any of these, like the to fungi, if they require entry through either wounds, or, natural natural openings, like stemmata into the plant, I guess I would make a huge note, that would be a big part of the answer to that question, right? Because they obviously wouldn't have access to any of the above ground entries, typical entries into the plant. But if it's just wounding, then yeah, you may be able to transmit them. And I'm not sure how Erwinia works. How it's been a while since I look at Erwinia, I can't recall how it did actually infects a plant. Certainly the other part of it is, they do tend to dry up. Not completely dry, but the potato surface, the cut potato surface isn't necessarily what the entire time, but it's still enough to attract the the maggots. But yeah, this is a really good question. I'm glad you brought it up. I'm gonna move it right up to those who know more about this than I do. - Yes, I actually, I plan on consulting our plant pathologist here at MSU, and see what their thoughts because this is a very common recommendation too and it's something I hadn't considered before. But it's a fantastic question. We've got another one. So, how long will the nematodes survive with adequate food? - So, they sort of will just perpetuate indefinitely if they have enough food, really, really, depending on temperature, of course. But like, if it's getting pretty far into winter, and it's getting super cold everywhere, then I mean, you're probably not gonna have nearly as many pest anyway. So, like I said, the surname FLTA they will go deeper down into the soil to avoid the cold. And then that actually slows down their metabolisms and their bacterial metabolisms, so that yeah, like everything's just slow down, and that they can overwinter decently well, but if they if they have pests that they can consistently get to then they'll just consistently make new nematodes. - Hey, Carly, did you have a question? You could turn on your mic if you want to. If not, that's okay. Carly may have something she wants to contribute to that we'll see. I've got a question for you. This is a situational question. And one of the reasons why we invited you here today so many of our growers have tried using nematodes quite a bit and other soil predators. And they some of them really, really struggle in the propagation phase. And this happens especially in spring crops like in January and February and even March when it's a little bit cold but a lot of sunshine especially here in Michigan it's not drying out the substrate very much, right? And so, you get pretty large populations of fungus gnats, and shore flies rather quickly and it seems like they can never get ahead of that curve. And they're I've been walking with them and they're wondering out loud said okay, it's not drying up right now. Why am I applying nematodes with more water? Am I just making the environment better for fungus gnats? Is there is there is there a way that like, especially like in propagation like really early on when it everything has to we have to really have to maintain the moisture. Is there some strategies that they can they can use? - Well, usually propagation is a lot smaller square footage, right? So, without bringing your expenses up much, I would say, increasing the frequency of applications and include increasing the rates, right? That may help you. Also use as many strategies as you have. So, include that BTI. And, certainly the other one that to think about is control your algae, if you're able to use algaecides on the soil surfaces, that's probably gonna help you. So, it's just about integrating as much as many weapons as you can to push, the push the advantage to your side. - And with the nematodes, using both Steinernema feltiae and Steinernema carpocapsae, they can really help because they live at different levels in the soil. So, the SF we're gonna be I mean, we'll plug tree like you're going so far down, they can go anyway, but they're gonna live just under this old surface, whereas carpocapsae, like I said, they're gonna be doing that nictating, nictating motion on top of this little surface. So, that just sits at different levels too. Something else that you can think about is those the lower breeding boxes like Saul talked about. I've seen those use supplementally in places that just have terrible fungicides that in short flight problems yearly. And it really does help reduce it. Also, just broadcasting both the strats and the Dalotioa on top like right from the very beginning, before you have a shore fly, or fungus gnat larva in there really helps like start early and be consistent. - Okay. So, like breeder boxes, so those things that are like you could just hang on the plant or somewhere nearby. So, what we're talking about? - Just nearby, and you wanna start out with about 500 beetles per box, I have a whole PDF that tells exactly how to do this, if somebody wants to email me about it, and I'll be happy to share. But one box generally covers about 4000 square feet. - Okay. - So, and like I said, it is just a supplement to broadcasting it's not a replacement for it. So, on all of those young plants, you definitely wanna sell broadcasts, both the straps and the Dalotia on top. - Okay. - And stay ahead. Also, if the seasons coming, load up ahead and stands preventative for as long as possible. - Okay, so have you guys, so maybe you can just help me here. This is like a like a Jeremy session. So, if we've got growers that find themselves, they're behind the ball a little bit, they didn't mean to, but they are and they're struggling. Have you ever worked with growers who have been at that point? And been able to bring them back around to where they didn't have to apply something like orthane as a drench or something like that? - Oh yeah please don't do that. - Yeah, well, it worked. - Yeah, that was really good Yeah, so normally, my suggestion is, control your irrigation. And you and you really that's the bulk of the control for fungus gnat, right? Everything else is kind of supplemental. One thing I forgot to mention as IPM for fungus gnat goes, when I worked at the mushroom farm, there's a lot of work being done on cinnamaldehyde and its repellent properties to fungus gnat particularly Sciaridaes. So I've been encouraging growers to use, fungicide, I mean, insecticidal oils that are based on cinnamon oil. There are a number of them, there are a number of organic ones. It's something that we haven't worked with enough. And I know at the time, I'd read I read a few papers and the head grower had actually done a lot of trials on cinnamaldehyde in for repelling Sciaridaes. And you know every technique that you can that you can come up with trapping, the yellow sticky tape, I've seen people using that. And I've mostly seen people using it incorrectly. You just have to have you have to have enough of it around for it to make differences. As he said fungus gnat in particular. I think what we're mainly worried about here is they're not good fliers. So, if you've got a tape set up, every 100 feet, you're gonna probably control a couple of feet around that tape. So, if you can figure out a way to do it, just increase the density of the tape that you apply and then particularly during those times of the year where they tend to blow up, you can knock down some of the swarms that way. - And where you put the Sticky, sticky cards can matter too. So, for fungus, that's like Saul said, they're not strong fliers, so they're not gonna fly up very far. So, if you have a bunch of cards that are way above the canopy line, you're not gonna catch any fungus gnats. If you have the sticky tape or the sticky cards just above soil level, you catch a lot of fungus gnats, if you're monitoring for thrips, you want the sticky cards above the sort of the canopy level because when thrips go from plant to plant, they tend to go up and over fungus that's on the other hand, they just kinda go in a straight line, they rarely go up and then they're gone. - That is very interesting. I've seen a few growers who will put this whole sticky tape onto their spray booms as it's going maybe a few inches, just a few inches above the canopy. Does that sounds like a decent idea? - Just above the canopy, that would help a lot for thrips. - Okay. - Like I said, depending on how tall the plants are, yeah, that's gonna really depend because it's all about soil level for the fungus. Like they don't have to go very far above it. - All right, we've got a few more that are coming in. So, is there a chemical control that you can recommend, in addition to the bios to have a well rounded IPM for fungus gnats, shore fly. And they use an example something relatively close to Vectoback. - I was answering a question. As I was answering Suzanne's question, and if there's anyone asked about the vectoring of diseases through the potato wedges, that's I don't know, Suzanne, maybe you wanna weigh in on that? - Yeah. I have a few people that I could try to ask to. - [Suzanne] I was trying to type my answer. - Hi, Suzanne. - [Suzanne] So, I was trying to not be here. I'm in the background laying low. So, every time we've done this, I've never seen a problem with it. Also, remember, we're talking pretty broad on geniuses of pathogens. And I don't know if the same pathogens that are in potatoes are the right species that would be able to move to ornamentals because we're talking pretty broad there. So I mean, I know there's a few like with the geranium that they just shut everything down over the the disease that we detected again this year. - Oh, I heard it, yeah. - [Suzanne] And they shut down the greenhouse, that was in Canada, it comes in on geraniums like that one we know can be spread to potatoes. And that's where they were kinda, I think it's a bacterial blight. Come on, I know-- - It's several of them. - [Suzanne] No, but there was one in particular. That's the really bad one again, I mean, everybody, it's geez, whenever it shows up, and it was in I think there was one detection. I thought it was in Michigan. - It is. I know what you're talking about. I'm having a brain failure at the moment. - [Suzanne] We're all having a brain failure. But anyhow, so we're, I've done that in. We've done I've never seen a pattern of vectoring with it. Also, I did a little differently. But that's that's fine. But also we you don't leave them in there forever. We're usually in there 48 hours, and then you remove the potato when you're gone. So, it's a pretty quick, in and out on that. And sorry. So, I thought you were talking to me about the question back to the cinnamaldehyde. So-- - Oh, no, no, no, it was the Erwinia. I just answered the question for the cinnamaldehyde. And yeah, that's a very good, good concern. Well, good work and concern and toxicity. But also, most oils are phytotoxic. It's just about finding that rate. And the question is, you're using it, if you use it at the very low rate, I mean, the label doesn't a lot doesn't limit what how low you can go. Will it still be repellent? That's the question. - [Suzanne] Well, it used to be sold at a product called cinnamate. And it hit the market really hard. I'm guessing this was about, I don't know, 15 years ago, and all the growers were excited to try it because it had some pretty good model setup properties. But there was just so many phytoissues with it that everybody's like yet, nope, not happening. And then my understanding is that's it went to the Pacific Northwest and everybody used it for liver wart management until the supply chain was gone a bit. So, just a warning there about that. Because there was so many phytoissues with the registered cinnamate product that was registered for plant use. - So, that there's two options other options since we're naming products, weed zap is cinnamon oil based, organic herbicide. Obviously that cannot be applied to crops, but It can be applied to areas under crops where they're where there may be weeds and then again cinnamon oils and I don't know if you've ever been in a greenhouse after a cinnamon oil application but I mean it'll take a day at least for that it's really annoying smell and then there's Sciaridaes which I think is what they took place of cinnamite, after cinnamite left the market. Cinnamite is registered to apply on crops. But again, you just wanna be careful wanna watch your temperatures and how well watered the plants are et cetera. - [Suzanne] Yeah, and that that respiratory thing about is no joke, because if you're doing this, like let's say, in a nursery outside of North it's one thing, if you do this in a greenhouse in Florida, because I've been in I will say cinnamon houses, garlic houses, rosemary, oh girl and it can be overwhelming. So, you have to think about workers stuff too. Workers not being in the area because it can be pretty tough on on breathing exam. (mumbling) - I agree 100%. - Okay. Thanks so much, Suzanne, appreciate it. Okay, another one. Very basic principle is that fungus gnats are in every current commercial mix. So, they come in with every new batch of plants that are placed in the greenhouse, I lightly grease French and nematodes especially propagation helps keep up the attack on the pest. Not a question, buddy. - Absolutely, yeah, agreed. - Agreed. - He's agreeing with you. For nematodes, you say to apply with as little water as possible, do you mean that the dosage of Nemesis for example is with too much water or when an adequate number of nematodes, or what would be an adequate number of nematodes per gallon of water? - So, the number of nematodes per volume of water is meaningless, the water is just the carrier to get them to where they need to go. So, it really just depends on your particular setup as far as how much water volume you need. Obviously, you wanna use the correct amount of nematodes or just a little bit over to ensure that you're getting the correct rate. But it just all 100% depends on how much water isn't gonna take to get them to where they need to go. So, for Steinernema feltiae, for example, like I said, you wat to water what actually water them in very lightly. But not nearly as much as you would if you were actually irrigating your plants, because you wanna give them about an inch, maybe two inches down below the soil surface for Steinernema carpocapsae. Since they live on top of the soils surface, you want to use as little volume of water as possible to just get them on that sort of surface. If that makes sense. - It does make sense and someone helped us out that disease we were looking for was Ralstonia. And that is that's what everybody yeah, you don't want that. That's a that's bad news. Okay. Yes, I think. Yes, absolutely. Yes, thank you to our audience. Really appreciate that. All right, so I don't believe we have any more questions. There was a lot of chitchat today, and I love it, it's perfect. Yeah, so I think that pretty much wraps up our final session for the season. Saul, Greg, thank you so much for sharing your time. And you're most welcome. We really appreciate it. Yeah, it's been a time-- - any time. - So if everyone, if you've enjoyed these seminars, as much as I have on, it's been a whole lot of fun for me. We have a few things that are on deck at the moment. And it's gonna be happening into in the Greenhouse Growers Expo this year, the 2020 Expo like just about everything else has been 100% online. We're fortunate to have Raymond Cloyd from Kansas State University come back and share some of the insight that he's gathered over the decades in the industry and in several books. Both sessions this time, we're gonna be focused on biological control. Mary Hausbeck from Michigan State University is always kind enough to share her latest updates on greenhouse disease control and she would be another good person to talk about that disease in the potatoes along with two. I'd be interested in hearing her opinion. We're also very pleased to have Rick Gates from Griffin Greenhouse Supplies come in and speak about pest management and retail greenhouses, which can be a little bit challenging because of their public nature. It's a slightly different beast. There are also sessions on plant production, retail sales and manage marketing plant varieties and landscape performance, specialty cut flowers this year and a handful of other relevant sessions. It is 100% online, which means It is easier than ever to catch some of these excellent speakers. So, for registration information, please go to Great Lakes, www.glexpo.com, that's glexpo.com. Thanks again everyone. Hope to see you again. Have a great week. - Bye. - Thanks.

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