Pesticide-Free Pest Control  American Hydroponics Webinar [Replay from September 21, 2017]

Hi, good afternoon, I’m Joe Swartz from American Hydroponics. Thank you for joining us today. We’re going to talk about how biological pests, insects, and disease are some of the biggest challenges facing growers today.

So, it’s very very important to understand what’s going on in the greenhouse and find better ways to deal with it. One of the most common questions I get from people is “what is this in my greenhouse or why do I have this big patch of dead plants?” So what we really need to do is first talk about the importance of being very involved in scouting every day. We are here today in the Humboldt County Office of Education greenhouse.

This is a high school greenhouse training center for students at the Humboldt County Office of Education and it is a student run entrepreneurial operation. This is also where we have our AmHydro two day seminars. This is a working greenhouse, it’s a training and research facility, and what you see here is a wide variety of crops where students are not only learning to grow, but they’re also learning how to do research for different varieties pests and insects and understanding the biology of all that is a lot going on in this greenhouse.

By and large though, we don’t want to see pests and we don’t want to see diseases. I’m going to show you a few of those today and talk about strategies of how to deal with pests and diseases that don’t involve pesticides. So, as I said, on a daily basis it’s very important to go through your crops and check on them. Here are our nursery plants and this is one of the most vulnerable times for insect infestation.

So it’s very important to not only check your plant and look underneath for anything unusual like insects, disease, etc., but it’s also very important when you’re transplanting or handling things to understand what’s going on. So if you’re not doing it yourself, it is important to train people who are working for you to look for things that are unusual. Insect pests are one of the most important challenges that growers face, so it’s very very important to understand quickly how to identify what may have in the greenhouse but also what to do. As we go through our greenhouse tasks every day, we may notice certain insects when we do. There’s a lot of resources online for identifying insects and as part of our grower training program at AmHydro, we do tutorials on insect and disease identification. This is very important but it’s critically important in early stage to know what’s going on.

So let’s talk about just some of the most common insect pests we deal with. One of the most common is aphids. Aphids are universal across all climates, all regions of the world and they’re most common in leafy greens but sometimes we see them in tomatoes and peppers and fruiting crops as well. It is important to understand what aphids look like and, as you can see on the screen, the adults, which tend to give live birth which means they replicate very quickly and they tend to cluster as one of things we know about aphids because they tend to cluster on the undersides of leaves. So during your inspection it’s very very important to be able to look, not only on top, but underneath on the bottom sides of the leaves. Many different insects will come to the undersides and they’re not commonly seen until they rise to epidemic levels which is what we don’t want to see.

Aphids are very common, but we have certain strategies we’re going to talk about a minute to deal with them but we’ll move on to the next most common insect pests and those are greenhouse whiteflies. Tomato growers and pepper growers tend to see these all the time again these will probably be on the undersides of leaves. One of the differences, though; these are flying as adults. So when you’re moving through your crop and you brush the crop you tend to see them flying and moving around, so they’re a little more obvious in terms of seeing them but usually when we see them they’re already adults meaning there’s a lot of larva and young on the undersides of the leaves. So if you don’t see them until the white flies are flying around, you’re a little bit late, but we do have some strategies to deal with whiteflies.

Next are thrips; thrips again, like aphids, are pretty universal we see them all over. We see them on the upper sides and on the undersides of the leaves. They’re very very tiny and you almost never will actually see thrips themselves. If you look at the picture on your screen that’s actually thrips damage, the thrips themselves are almost microscopic. So we have to learn to identify not only what the insects look like but the damage that they cause and how to look for that.

And lastly our second last, we also have leafminers that are very very common for growers of floral crops and also tomatoes. This very distinct pattern looks like a squiggly line that moves around on the leaves.

This is actually a fly that lays eggs into the leaf tissue and that is basically a larva eating its way through the leafage. These can cause a significant amount of cosmetic damage and it’s very important to identify them and treat them quickly.

And lastly, Spidermites are also one of the most common. Now keep in mind that this is not the only list of insect pests that you deal with these are the most common and cause the most economic losses. And as you can see from the photograph of the spider mites one of the most telltale signs is this webbing and leaf distortion. Again, Spidermites are almost impossible to see so we have to learn to identified their presence through either their webbing or how damaged the leaves look.

So there’s a couple of strategies that we like to use. This is specifically for pesticide free growing with some growers choosing to use organic standards or going completely beyond organic, what we call pesticide free standards. So very very important to understand what tools we have available. So what we tend to like to use mostly are different beneficial insects to battle that we like to call them the good bugs and the bad bugs. So the first photograph we’re saying is the ladybug. This is the most one of the most common and universally known predators. Basically these will eat just about every insect pests known to man. They’re commonly brought into greenhouses to deal with aphids and other infestations. These are predators and they will aggressively go out and basically eat the aphids or other insects whole, so they come right in and eat the bad bugs. That’s one common, fairly universal insect that use. One of the more effective long term strategies that we like to use are parasites.

What these do is they tend to search out the insect pests and they lay their eggs inside the bodies of the insect pests. So while the insect pest is still alive, they’re basically serving as an incubator for our beneficials, and so it slowly kills your insect pests and breeds more beneficials. In a greenhouse environment where we’re not using pesticides we’re trying to maintain a very active ecosystem with what we call bad bugs. We want to keep a good population of the good bugs and there are a number of products to bring in the good bugs.

So these are just two of the very common insect parasites that we like to use. So for the aphids that we talked about that are very common, this good bug is called aphidoletes and these are actually a very very tiny wasps. They are shipped in a mixture of bran and the small pupa of these are actually shipped and so if you can see some of the light color bran then you see dark spots these are actually the aphidoletes and these are shipped to you in a refrigerated package. So they’re basically dormant.

So when you bring them to your greenhouse we have small containers, these are just small cups. And what we do is we hang them up and once they’re in the warm greenhouse environment they will develop very quickly and within 24 to 48 hours they will emerge. And once they do they will search out the aphids and they will begin laying eggs in the bodies of the aphids. We just hang them out in a convenient location within the crop, and then as we say, the affiliates will then venture out and start work.

It’s very important though to understand which insect pests that we’re dealing with that we know how to deal with them. Now were going to go over the tomatoes really quickly. This is where we tend to see whiteflies and spidermites. Now this is neoseiulus cucumeris. This is also the small predatory mite. All we want to do is we take a small amount of it. It also comes in a bran carrier.

Unfortunately, you can’t really see these very well but they will come out just like the aphidoletes in a warm greenhouse environment. So what we will do is we will have them in various areas around our crop. And some growers also will just simply sprinkle the bran carrier around the crop. So basically now the cucumeris mites will migrate into the tomato crop and it will be working in 24 hours. It’s very important in terms of dealing with insect pests to be able to not only identify them and deal with them once you see them, but also to keep them out of your greenhouse as much as possible. When we deal with biological insects it’s very important to realize that we don’t have a quick fix. We can’t come in and do one thing that will take care of all of the insects. So our first line of defense in any insect infestation is exclusion. Properly run greenhouses all should have insects screens. This is basically in all of the vents where air can come into the greenhouse and they have a mesh screen that excludes most insect pests. This will go a long way and it’s a very simple method for keeping as many greenhouse pests out of the greenhouse as possible.

Also you know pests can come in on your clothing and things like wearing street clothes in anything else at all times sometimes can be problematic. So it’s important to have a pair of shoes and maybe other clothes to wear so you’re not bringing your street clothes into the greenhouse. Here at the HCOE greenhouse all workers are required to change their shoes and we have disposable shoes that they can wear. And it’s also very important to keep a clean greenhouse, we can see here that the floors are kept clean and that there are no weeds anywhere. Weeds are excellent vectors for insect pests.

Your sanitation practices are going to be very important when dealing with insect and disease pests which is why it’s very very important to keep very clean greenhouse and be in it every day. When you’re transplanting crops, when you’re harvesting your crops, when you’re doing a daily check, you should always look for presence of insects so you can catch an infestation. Both insects and diseases start usually very very small but they can develop and spin very rapidly so the sooner you can treat these infestation, the better. We mainly use beneficials for insect exclusion and eradication. We also have biological control of disease which is very important as well. Most fungal and bacterial diseases cause significant economic losses in greenhouses and you can avoid it with environmental control and proper sanitation.

One of the most common things people ask me about first and foremost is powdery mildew. This is by far one of the most economically devastating fungal diseases and it’s called powdery mildew and it’s very easily identified by white powdery material on the upper sides of the leaves. People will call me and say that they have their looks what looks like talcum powder on the leaves, this is a very early stage of powdery mildew. You can see individual spots of powdery mildew, that happens fairly quickly though as you see in this dill plant, the powdery mildew has spread across all of the leaves.

We tend to see is what looks like a powdery substance that starts on the older leaves and works its up. Powdery mildew is a fungal disease that spreads very very rapidly under certain temperature and humidity conditions so it’s a very very important to understand what it looks like and to keep your crops in proper growing environments to eliminate the potential for disease. Downey mildew is very similar to powdery mildew and one of the only differences is rather than seeing on the upper sides of leaves is that you’ll see it on the undersides of the leaves. So again, it’s very very important to not only check to see what’s on the undersides of the leaves, but to also check on top. So when looking for insects, you may look underneath and find aphids which we wouldn’t find on top, and see powdery mildew the top as well downy mildew. Again, it’s very very important to understand temperature and humidity, which we will talk about in a second, but it’s very good to catch early.

Fungal blights are also common in greenhouses. These can be several diseases such as septoria and anthracnose which are generally fungal, sometimes bacterial diseases that will appear as dark spots on the upper sides of the leaves. Once you start to see these, you already have an infection going, so it’s very very important to eliminate or remove any infected plant material and identify and treat it as quickly as possible. So how do we deal with these? First and foremost are environmental controls.

Understanding the proper temperature and humidity range for our crops is very very important because the ideal temperature and humidity range for our crops, in most cases, is actually a less than favorable ideal condition for the diseases. We tend to see powdery mildew get going in spring and fall when our greenhouse temperatures may fluctuate too much, when the relative humidity level is too high, or when our nighttime temperatures too low. So these are conditions that you as a grower can eliminate which will then significantly lower the incidence of some diseases. Downy mildew and fungus blights also vary in temperature and humidity so keeping your humidity in the proper range usually 55 and 65 percent range but again that’s temperature and we could talk to you and future seminars and also call us to talk to you about your humidity ranges and pressure deficit level which are ideal levels of temperature humidity.

Now again as we did with talked about with insect infestation having a very very clean green house keeping out foreign plant material very very important. Every year we have growers that fall into disease infestation and they’ll happen to offhand mention that they’re storing their neighbors coleus plants in their greenhouse. And what they’re doing is they’re bringing an insect disease problems into the greenhouse. So it’s very very important to keep your greenhouse sealed and not to allow any other foreign plant material in your greenhouse. Every week when we harvest it’s very very important to clean up all material that could vector insects and diseases.

It’s very very important to keep control. Some growers who don’t use chemical pesticides can use biological materials there are certain sprays such as bacillus subtillis which is a very common it’s an actual bacteria and it actually will coat the leaf surface and inhibits the growth of some of the other pathogenic fungi and bacteria. So it’s very very important to understand which materials are available to begin with and we can help advise you in that. Some growers actually use food products like potassium bicarbonate as well which is known to inhibit. So things like that are all very very important pieces to your toolbox if you will to battle insects and disesase.

So again it’s very very important keep good agricultural practices all the way through. It’s very very important to keep foreign plant material out, to keep your greenhouse clean, and to use biological pest control products like this which we can advise you on. That is the foundation for a good strategy for quality biological insect control. So again it’s also very important to scout daily and be able to identify and respond very quickly. I hope you enjoyed that and I hope that made sense, please feel free to contact us if you have questions. This is kind of a very short overview of a very large and complex subject. We do talk about in much greater depth at our introduction to a hydroponic crop production seminars these are two day seminars and we have one coming up here on October 26 and 27. We have a greenhouse portion of the seminar, we have some classroom instruction and then we have a lot of time and the greenhouse were we’re at this greenhouse here in the HCOE.

So you’ll spend time in the greenhouse working with plants and learning to identify pests and diseases, learning crop production strategies, and learning a lot of very important information to starting your own hydroponic greenhouse. So we really urge you if you haven’t already to join it. If you look on the screen there’s information we also have a special two for one special that basically two people from your operation can come for the price of one. You also have to specially see on your screen regarding special for hotel accommodations. So hopefully we will see you in October at that. And we also have an upcoming webinar which has our next weather which is coming up in October and you should see the information on your screen and we’ll be talking about heating and specifically heating your crops and your seedling system or your propagation system for maximum crop production.

As we go into winter months growers have a slowdown in growth and revenues will go down. So we want to look at some strategies to keep your crop growth moving onward and moving at a fast pace as well as keeping your quality. So thank you very much for joining us. I appreciate your time. If you have questions please contact us and we hope to you at our upcoming seminar and our future website. So thanks and have a great day.



Joe Swartz

Author Joe Swartz

Involved in all aspects of the Hydroponics Industry. Currently in my 32nd year as a commercial hydroponic vegetable and herb grower. (Over 50,000 hours of greenhouse production time). I am experienced in all levels of design, set up, crop scheduling, workforce training, and specialty produce marketing. I have consulted for growers/investors across the United States, Canada, the Middle East, Western Europe, the Caribbean, and Asia.

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