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Aphids only on milkweed in a blueberry block

These milkweed plants are being consumed by aphids while the blueberry leaves inches away have no aphids on them at all. This is a clear indicator that the soil microbial population and mineral balance is more supportive of blueberries than it is of milkweed.

The aphids are attracted to the unhealthy plants, and are taking them out of the ecosystem. If the milkweed were healthier than the blueberries, the aphids would be on the blueberries, and leave the milkweed untouched.

Since the aphids are now consuming a plant that might be considered a ‘weed’ in this particular context, does that make the aphids a pest for attacking the plants, or a beneficial ‘biocontrol’ because they are removing the ‘weed’?

2020-06-25T13:37:14-05:00July 10th, 2020|Tags: , , , |

Unhealthy people attract mosquitos, just like unhealthy plants attract other insects

Insects will only eat that which is digestible to their system.

From the interview with Tom Dykstra:

John: I have friends who will attract every mosquito for dozens of yards around, and others who, for all practical purposes, are mosquito-immune. Can you describe the differences?

Tom: I hate saying this, but that is the difference between healthy people and unhealthy people. If you have digestible blood, the insect can use your blood. If you have healthy blood, the insect is not attracted to it. Does this mean you’re healthy all the time? No. People have certain states of healthiness and unhealthiness. But as long as your blood is digestible, it’s going to be attractive to an insect.

It’s the digestive system. Insects do not have very good digestive systems. Stuff has to come in digested to them because they cannot digest things. They just don’t have the enzymes. They’re garbage collectors. They eat muck. They eat garbage. They eat bad stuff. They eat stuff that we don’t want to eat. Take a look at cockroaches, for example, or fruit flies. They’re always around decaying fruit. They’re not around healthy fruit. These insects that are keying in on very specific plants. Or even, let’s say, the fruiting structures of a tomato—that’s what they are keying in on.

Mosquitoes need something that’s digestible. When they take a blood meal, it must be incorporated through the process of vitellogenesis: taking those nutrients in your blood and incorporating them into an egg. This occurs in about twenty-four hours—very, very quickly. So if they’re not getting digestible blood, they cannot, through the process of vitellogenesis, take those nutrients and feed their eggs. And that’s a problem, because obviously the mosquito wants to feed its egg. The only reason it takes a blood meal is to feed its eggs.

We do have these differences among individuals. Some are just more digestible than others, and they’re going to be more attractive. Grasshoppers have a choice as to what crop they eat, and mosquitoes have a choice as to what blood meal they wish to get. Through their antenna and all of their senses, they detect that someone is more digestible than another, and they’re going to go after that individual. Even though that may offend some people, I do feel an obligation to tell the truth the way that I know it, according to the information that has been given to me for the past twenty to thirty years of my life studying insects.

John: I very much doubt that you’re offending people. I would say that you’re simply communicating some very intriguing ideas that many of us have observed to be true in real life and have wondered about the differences. So thank you for sharing that.

Tom: I’m happy to do so. When you go to the supermarket and you see fruit flies flying around the tomatoes, some people think, “Oh, I don’t want these tomatoes—they have fruit flies in them.” But honestly, all you have to do is find that one tomato near the bottom that’s injured, and that’s where all the fruit flies are located—near the one that’s unhealthy. And that essentially equates to that which is digestible. A tomato that is degrading—that is decomposing—is being broken down. And when it’s being broken down, it’s digestible. Insects will only eat that which is digestible to their system.

2020-06-23T14:38:59-05:00July 2nd, 2020|Tags: , , |

Insects are only attracted to unhealthy plants

An excerpt from the podcast interview with Tom Dykstra:

John: What do you believe to be true about modern agriculture that other people may not believe to be true?

Tom: Insects are only attracted to unhealthy plants.

If you believe that insects are attracted to unhealthy plants, your whole thinking changes on insects. Suddenly you have no use for insecticides. It just follows with that level of thinking, because you realize, “Well, I’m not competing with insects. They’re just eating some of the garbage plants that I shouldn’t be eating. So I really don’t need to spray them anymore.”

So now all the organophosphates and synthetic pyrethroids and carbamates and neonicotinoids—they’re all unnecessary. As you reason through this, that’s one of the conclusions you come to. You have to come to it when you believe that insects are only attracted to unhealthy plants. I don’t even have to come out as an anti-pesticide guy. I can simply say that insects are not attracted to unhealthy plants. And by extension, I would say, yes—insecticides are unnecessary.

Under specific circumstances, they have their role. I will be the first to admit that I’ve had fire ants. Sometimes they come into the house. I do have a Raid can in my house. And we have had situations where the kids would leave food crumbs around. And the situation has to be taken care of. So I’m not afraid to use insecticides, and I understand that they have their place.

However, having said that, when I’m raising crops I’m never spraying it with anything.  I don’t have a knowledge of all the insecticides, but I don’t use any of them. I’m not using any herbicides or fungicides. I use insects as indicators. I go out and check my corn plants, for example, and I look to see if they’re being attacked. And if they are, I determine what insect is attacking them, and I figure out why they aren’t healthy.

For example, the first time I started planting corn, I did have a few insects that were attacking it. By the third time that I was planting corn, no insects were attacking it, but deer came in and cleaned me out. This is the difference between the insect digestive system and the mammalian digestive system: we have a higher-level digestive system. We can handle healthy food. The deer are more interested in healthy crops. They’re not going to go after unhealthy stuff. They’ll leave that up to the insects.

Insects consume unhealthy ‘weeds’ growing in healthy soil

Not all plants grow equally well in the same soil. Each plant has a preferred microbial, physical, and nutritional environment it thrives in.

When soil balance is optimized for our domesticated plants, the crop plants are healthier than the weeds. Now, the weeds have lower brix readings, and are more susceptible to disease and insects than the surrounding crop.

These lambsquarter plants were growing at the intersection of three fields, growing tomatoes, mixed salad greens, and peas. The last two crops can be very susceptible to aphids. There were no aphids to be found anywhere on the crops, while the lambsquarter was being consumed, as you can see.

2020-05-16T12:48:30-05:00May 19th, 2020|Tags: , , , |

The degree of protein synthesis determines insect susceptibility

Plant absorption of ammonium instead of nitrate influences the degree of insect susceptibility. Excessive nitrogen in any form results in excessive soluble amino acids within the plant that enhances insect development and population growth.

From the podcast interview with Larry Phelan.

John: I’d also like to understand the insect attraction piece a bit better. You mentioned that when you have this surge of nitrogen supply on the non-organic farms from the nutrient application period, you have an increased attraction because you have a nutrient-rich food source. Why can insects not utilize plants that don’t contain high levels of amino acids as a food source? They would also contain some level of amino acids, wouldn’t they?

Larry: Yes, all plants are going to have some levels of free amino acids, and they can also digest protein—let’s keep that in mind too. But it’s going to take energy for that insect to digest that protein.

Furthermore, a lot of plants have defenses that involve the inhibition of enzymes that break down protein in the insect. These are called proteinase inhibitors. And in terms of what we call inducible defenses, this is one of the responses of many plants to insect attack. They start the production of these proteinase inhibitors in order to reduce the insect’s ability to digest that protein. It basically knocks out those proteinases in the insect. The insect doesn’t necessarily starve, but it slows its development way down.

Well, in that situation, if you’ve also given that plant these high levels of nitrogen and it’s accumulating these free amino acids, that now short-circuits that plant defense system. So, in other words, the insect doesn’t need those proteinases as much because it’s getting these free amino acids that it doesn’t have to break down.

John: Got it. That was a piece that I had always not fully understood. I’ve heard it described that insects don’t have the capacity to digest complete proteins and that they’re dependent on soluble amino acids as a food source. And that never quite made sense to me. It made sense from a theoretical perspective, but it didn’t make sense to me that plants might have no amino acids versus one plant having very high levels of amino acids.

Larry: Yeah, it’s a matter of degree. And even proteins vary in terms of their digestibility for insects too. And, of course, insects evolve enzymes that are going to be most effective in digesting the proteins they’re likely to encounter, depending on what host plant they feed on. 

How the form of nitrogen influences insect feeding

The form of nitrogen influences not only the pathogenicity of soil borne fungal diseases, but also susceptibility to insects.

From the podcast interview with Larry Phelan.

John: As you were looking at these plant-insect dynamics in the field and developing your hypothesis of biological buffering, what was something that surprised you?

Larry: The one thing that was particularly exciting to us was when we took the next step and tested this idea of mineral balance resulting from this biological buffering of organic matter. We started growing plants hydroponically so that we could vary the proportions of different nutrients. The hypothesis we were testing was actually that when the plant was in good mineral balance, you would get both good growth and resistance to insect attack. And then as the plant moved out of balance nutritionally, you would see plant growth go down and insect performance actually go up. And then, ultimately, as the plant was way out of balance nutritionally, we expected the plant to not grow very well and the insects not to do very well either because of the poor host plant.

We tested this with a number of different combinations of nutrients, and the one that was most dramatic—that actually supported this prediction—was looking at soybeans in which we varied the ratios of ammonia to nitrate in the plant. We provided it all the nutrients that it needed in constant levels for all the plants. What we were testing was different ratios between these two different forms of nitrogen. And what we found was that as we increased the amount of ammonia up to about 30 percent, we saw the best plant growth. That ratio of 30 percent ammonia and 70 percent nitrate is where we got the best plant growth.

And then, when we looked at insects, we plucked the leaves off of these plants and then fed them to insects to see how the insects grew. The particular insect we were working with was the Mexican bean beetle. When we fed these leaves to the Mexican bean beetle, we saw just the opposite response. In other words, where the plant was out of bounds nutritionally and not growing very well, that’s where the insects grew the largest and that’s where we saw the best survivorship. But as we moved towards that 30 percent ammonia level, where the plants were growing their biggest, insect survivorship dropped from about 90 percent down to about 30 or 40 percent.

It was a very dramatic effect—even more dramatic than what we were expecting. When we followed up on this and measured the levels of free amino acids in these plants, it was consistent with the prediction. In other words, those plants that were not growing as well, that were out of balance in terms of this ratio, had much higher levels of free amino acids relative to that 30 percent ammonia plant.

2020-05-05T05:16:18-05:00May 12th, 2020|Tags: , , , , , |

Nutritional differences in insect susceptible plants

Healthy plants are completely resistant to insects.

We have observed this to be true in the field on many occasions. Over time, more connections come to light describing the scientific reasons for how this occurs.

Larry describes their pioneering research seeking to identify the nutritional differences between insect resistant and insect susceptible crops in our podcast episode here.

So, if you have an imbalance—if you have too much nitrogen relative to potassium—what happens is you get the buildup of free amino acids in those plants. And insects love free amino acids. They’re a very digestible source of nutrients for them because they’re also highly limited by nitrogen.

 

John: With some of the original research that you did—comparing the insect pressure on the organic farms versus the nonorganic farms—this is actually something that I often hear from organic growers, but I haven’t uncovered a lot of research where people have actually tried to do a comparison and evaluate the differences. What were the differences that you were seeing? What really stood out for you?

Larry: Again, keep in mind that this was twenty to twenty-five years ago. There’s been a lot more research in organic systems now. But at the time, organic farming was considered very unscientific, and more New Age, and not amenable to large-scale production. And so I was working with a lot of organic farmers who were basically doing their own research—not necessarily replicated research as we would do at the university, but trying different things and seeing what worked on their farm. This is the context in which we got started.

I actually received a lot of criticism at the time—that what I was doing was not very productive, or not the direction I should be going as a non-tenured faculty member. So, we went to these organic corn and soybean farmers, and the ones we worked with had animals integrated into their system as well. First of all, we just did a census of their corn, looking at the levels of European corn borer damage in their fields versus their conventional neighbors. And, as I’m sure you and many of your listeners have often heard, I kept hearing this idea that if we have healthy soil, then we’re going to have a healthy plant and that insects don’t like healthy plants—that’s why they don’t see the damage.

Although that in itself is not a very scientific statement, we could reformulate it as a hypothesis that we could test empirically. And so we collected soils from these organic farms and then went right across the street to a conventional neighbor, collected their soils, and brought these soils into the greenhouse and planted them to corn. And we fertilized each of them either with an organic fertilizer, like manure or compost, or with a chemical fertilizer.

What we were interested in figuring out was, first of all, whether the insects could tell a difference in these plants. And if they could tell a difference, was it associated with that short-term effect of the type of fertilizer we used or that long-term effect of that history of management and how that impacted the soil community. And so, after setting these plants up and letting them grow to a certain stage, we released European corn borer females that had been mated into the greenhouse. All of this was replicated and randomized.

And we just let them loose to see where they would lay their eggs. And what we found very consistently—we actually repeated this experiment, I think, with four or five different pairs of soils from farms—was that if the plants were growing in a soil from an organic farm, irrespective of the fertilizer we applied, they received relatively few eggs. Whereas if the plants were growing in a soil from a conventional farm, sometimes they would receive a lot of eggs and sometimes they would receive only a few eggs.

This gave rise to this concept that I call biological buffering. The way we envision this—and this was our working hypothesis—was that in those organic systems, where you have a recurring influx of organic matter into those soils, either in terms of cover crops or plant manures or animal manures, you create this soil community that is beneficial to the plant. And when nutrients then go into that system, they get absorbed by this microbial community and then they release those nutrients very slowly over time. As a result, we hypothesize that those plants are in better mineral balance than when you’re putting down high levels of nutrients.

Why this would be important is because plants are almost always limited by nitrogen levels. They don’t have mechanisms for dampening the levels of nitrogen that they take up. They’re going to take up whatever they can get. And in this context of putting down inorganic, highly soluble nitrogen sources, often these plants are taking up much higher levels of nitrogen than they are really set up to deal with.

We then hypothesized that in this situation, those plants would tend to accumulate the simple compounds. When you have an imbalance of nutrients—let’s say nitrogen and potassium—if you think about those two elements, nitrogen is of course very important in terms of protein synthesis and potassium is important in terms of converting amino acids into protein. So, if you have an imbalance—if you have too much nitrogen relative to potassium—what happens is you get the buildup of free amino acids in those plants. And insects love free amino acids. They’re a very digestible source of nutrients for them because they’re also highly limited by nitrogen.

In situations where you have these imbalances, that plant becomes very nutritious for the insect; whereas in the plant that is in better mineral balance—one that’s getting its nutrients relatively slowly—that metabolic machinery of the plant is able to act more efficiently. As amino acids and sugars are produced in the plant, they are more immediately converted to the less digestible and more complex building blocks of the plant, like proteins and starches and cellulose and that sort of thing.

Developing disease suppressive soil

Diseases and insects only become a problem when plants are unhealthy, lacking nutritional integrity and microbiome integrity. The tools of nutrition management and microbiome management are so effective, they have been and are used as management protocols for bio warfare weapons mitigation.

From the Regenerative Agriculture Podcast with Michael McNeill:

John: Michael, we’ve been circling around this topic of soil health and the impacts of tillage, herbicides, animal manures, cover crops, and so forth. At the beginning, you mentioned that there’s a correlation between soil health and the diseases that are present. You mentioned some work you were doing in Maryland—studying diseases as a weapon. What did you learn from that experience? And how does all of that tie into what we’re talking about?

Michael: Let’s say you want to use a fungal disease as a weapon—that you can get this disease introduced into the soil. Not only does it kill a crop this year—it’ll continue to kill it into future years. So hey, that’s a pretty good weapon—you shut down a people’s food supply. They have a problem.

Well, if you have good pseudomonas bacteria in the soil, they act as a policeman in the soil, if you will, and they’ll take out the pathogenic fungi that can arise. But if you use products like glyphosate—that’s an antibiotic type of product—you’re going to kill all the pseudomonas, and then you have no protection. And it’s very easy to get a huge population of fusarium going in the soil, which probably is a pathogenic fusarium—or pythium or phytophthora. You’ve lost the natural balance. If you have that balance, though, the pathogenic fungi are not going to do much to you. Your good bacteria will clean it right up.

John: So you can actually have a disease-suppressive soil where you don’t have challenges with those pathogenic fungi. I think I also heard you mention that you were working on developing solutions to those diseases as weapons. What were the types of solutions that you were working on?

Michael: There are all kinds of approaches. If you need a fast cure, of course you’ve got to look at chemistry and the fungicides and that sort of thing. But what you find is that if you get the soil contaminated, how do you fix it? Because if you put anything on it, you’re going to kill everything in the soil. Using a soil sterilizer is not necessarily a great idea. But there is microbial life in the soil that will hold everything in balance. And if you have the right nutrition available, everything will take care of itself.

I’ll use you as an analogy, John. If your nutrition gets pretty poor, you’re going to get pretty run down, and you’re going to be very susceptible to all kinds of diseases. Would you agree?

John: Oh, I think that’s just the story of the people who are trying to sell me supplements. (Sarcasm, I take many supplements, and believe they are important.)

Michael: That’s funny—but when that occurs, you can take this supplement or this drug to prevent the disease, but you’re still improperly nourished. You’re going to get another disease, and then you’re going to get another disease. But if you get your nutrition back and properly balanced, and everything is at the correct level, your immune system starts to function properly. A good share of your immune system is in your digestive tract—there are a lot of microbes working for you.

And the soil is no different. You get those microbes working for you, you’re going to stay healthy. The soil is going to stay healthy, and so are the plants.

John: Are you saying that when you manage the nutritional balance of the soil and the microbial population of the soil, that it’s possible to grow crops that don’t have disease?

Michael: Yes. When a plant is perfectly healthy, it’s very hard to get a disease to invade it, and an insect will not even stop to look at it. Why is that? It’s because an unhealthy plant cannot convert the sugars it’s produced into complex sugars—starches and lignin—which insects and diseases can’t use. They can use simple sugars and the nitrate nitrogen in the plant. The nitrate nitrogen is taken up by the plant, and it’s immediately converted into amino acids and proteins in a healthy plant. An unhealthy plant—a plant that does not have the right mineral balance to make all those processes and cycles work—will have a pretty heavy load of nitrate in it—a fantastic food for the insect. They can detect that, and they will land on that plant and feed on it. Disease and insects are Mother Nature’s garbage collectors—getting rid of the bad stuff, the weak plants.

Pesticide safety assessments

A thought-provoking quote from Jonathan Lundgren on the Regenerative Agriculture Podcast:

My research focuses on two general areas. One is the risk assessment of pesticides and genetically modified crops and, basically, farm management practices in general. And then the other half is working on developing sustainable systems. So, I’ve got quite a bit of experience in understanding the ecological risk assessment in the framework that we use for trying to determine whether a particular agrochemical or something is safe or not safe. I’ve advised the US EPA. I’ve been on advisory panels for the European version of the EPA, the Brazilian government, the United Nations and their conference on biodiversity. And after twenty years of studying this, I can honestly say that when you look at the side of a jug and it says that it’s safe, that is meaningless.

You can go out and you can buy something off of the shelf and it’s labeled and it’s regulated. Nobody is watching. Nobody is watching! Risk assessment is incredibly hard. And we can get closer to the mark with scientific approaches to risk assessment, but again—when you understand the complexity of the natural world . . . ! 

Right now, just for pesticides, there are a couple of hundred different pesticides whose active ingredient is registered with the EPA. And that’s where most of the safety assessments are focused—on those active ingredients. But whenever you add an adjuvant—maybe it’s a sticker or a spreader or a defoaming agent or whatever—it changes the toxicology of that active ingredient such that the risk assessment that you’re actually performing on an active ingredient really does not hold much weight anymore. And think about all of the formulated products—there are 20,000 formulated pesticides in the US, and each of those pesticides would require an independent ecological risk assessment—each of them. 

We don’t have the first inkling of what the implications of these things are, be it glyphosate, neonicotinoids, propiconazole, or the adjuvants, which are sometimes more toxic than the active ingredient in terms of its ecological effects. And we’re not just talking about the soil, right? We’re talking about human health problems. Farmers have the highest suicide rate of any career at this point in the US. And we know that pesticide use is linked with depression. The science has been done on that. I mean, are we killing ourselves?

From: Ecosystem Diversity Prevents Insect Pressure with Jonathan Lundgren

 
2020-03-23T14:17:53-05:00March 24th, 2020|Tags: , , |

The Agronomy of the future

Will not be based on chemistry but on biophysics and biology.

In the future, soil analysis will not be looking only at mineral balance and nutrient levels, but at the levels of amino acids, peptides, enzymes, carbohydrates, and other compounds that plant roots can absorb from the microbial community.

Agronomists will look at soil paramagnetism, redox, and electrical conductivity to evaluate a soil’s capacity to deliver to crop yields and quality.

Crop scouts will measure plant leaf redox and electrical activity to determine disease and insect susceptibility, and determine what treatments to apply to prevent possible infections.

The emerging knowledge of this space that is becoming more widely known is extremely exciting.

I posted a few weeks ago about Olivier Husson’s work on redox. His work is much broader and deeper than can be described in the referenced papers. He has been kind enough to appear on the podcast and to share his work in-depth in a six-hour-long webinar that we made available as a free online course on the academy that you can find here.

This will be the agronomy of the future. Enjoy.

 

2020-05-05T08:58:03-05:00February 12th, 2020|Tags: , , , , , |

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