Agricultural Arabesques: The Art and the Science of Biologicals
I woke up thinking about how beautiful and elegant complexity can be. In a time of lean-everything and minimalism, I am often struck by the complexity of nature. While biology can be incredibly efficient, I would hesitate to call it minimalistic.
I grew up in rural Kentucky, surrounded by the seasons, wildlife, forests, agriculture, and our life existed in these rhythms of planting, tending, harvesting, and fallow. I was not particularly popular in school, and I found my greatest joys in being out on our family’s property alone in the woods with my chocolate lab, Buddy, or at the piano practicing for a weekly piano lesson, my favorite music being the slightly un-done works of Debussy. If you are familiar with late-romantic era music of the late-19th century, you may love (or be incredibly frustrated by) the “ordered disorder” you sometimes find. This was the same time of impressionistic art, think of the blurry, watery lines of Monet, and this was reflected in the music as well.
Listen to one of my absolute favorite pieces to play, part 1 of “Deux Arabesques” by Claude Debussy here:
An aspect of this piece that adds to its magical sound, is that the right hand and the left hand are playing in basically two different timings. The right hand plays in triplets (3 notes to a beat) and the left hand plays in eighths (2 notes to a beat). This makes it so that the two hands are rarely playing at the exact same time. They share a time signature, but they’re operating sort of independently to one another. Debussy loved using this in his pieces. It can be incredibly difficult to learn how to do when you’re learning piano. Your brain inherently wants to play both hands together. It’s like clapping your hands to one rhythm and tapping your feet to another. But in its complexity, it’s actually still ordered, and this creates the most magical, beautiful, sort of wild music. It is controlled, intentional, and is not chaotic, but it’s not minimalistic or simple. It’s in this ordered messiness that its beauty is apparent.
I think biologicals exist in this world of seemingly chaotic, dis-ordered order. And in this complexity, also lies their value. Biologicals are notoriously frustrating, sometimes to the point of seeming un-reliable or ineffective. And I’m not really here to discount that if a product doesn’t do what its label claims to do, that is unreliable and ineffective. However, I am here to argue that maybe we don’t fully understand how a biological product works, so we don’t fully understand how to use it.
Let’s walk through an example.
Note: this is a hypothetical example. I’m not referring to specific products here to avoid any discussion of claims with specific companies or labels.
Product label: Apply this product alongside your fertility program, via foliar spray, to improve plant health and reduce the severity of disease. 16oz/acre, regardless of crop, regardless of carrier volume, anytime.
Case Study: Grower in the northern US tank mixes product with application of Zinc, Manganese, Boron at V10 corn, in 10 gallons per acre of water carrier.
Outcome: Common rust was already present from earlier, cooler and wetter conditions, and the induced resistance from the biological product wasn’t effective, as the pathogen was already established, despite symptoms showing up later. Symptoms still showed up, only about 10% less severe than in untreated acres of the same region.
Grower’s Conclusion: The product “didn’t work” very well.
*Actual* findings: The timing was not exactly right for that product to work in that way, for several reasons.
It wasn’t clear that the product works by eliciting systemic defense responses in the plant. At V10, corn is in a later vegetative growth stage. While still sensitive to induced resistance mechanisms, an earlier application may have elicited these responses a bit stronger.
The pathosystem for rust wasn’t fully understood. The causal pathogen for common rust (Puccinia sorghi) favors cool, wet conditions. These conditions were met earlier in the season, which allowed for the pathogen to get a foothold and infect the crop. Earlier application of the product may have helped induce resistance in the crop during or before conditions were conducive for this pathogen, and either lower overall incidence of rust by making crops more resistance, or by delaying the severity of disease from early season, buying the crop time to get to warmer weather when conditions were less conducive for rust infection.
The induced resistance mechanisms that this product elicits in the crops need at least 2 applications for maximum expression and effectiveness. With a carrier rate of 10 GPA, this is quite concentrated for the 16oz/acre recommendation, and early applications at this rate could have over-stressed juvenile plants. Optimal application would have been perhaps 8oz/acre, in 15 GPA carrier, with a couple of applications before V10, perhaps with an in-furrow application at planting, and with a post-emergent herbicide around V4-V8. Growers of crops using much higher carrier rates, such as apples with sometimes upwards of 100 GPA, might need significantly more product to obtain effective dilution rates of the product.
There are other considerations that could have helped get better results as well, including the hybrid that the grower used, any existing nutritional deficiencies that could have impeded full expression of these defense responses or made the crop more susceptible to infection, the conditions and life cycle (“pathosystem”) of the pathogen that’s causing the disease we’re measuring, and more.
My point with my pretend case study is not that there is this sort of infinite list of things that can impact how a crop performs during a season. My point is that when we don’t have all the information about how a biological product works, what we’re trying to accomplish with this product, and why it needs to be used at certain rates, application frequencies, and application timing, then how can we expect to see effective results?
Our instinct with how we understand and research crop inputs tends to be a bit more cut-and-dry. We want “apply product —> see results”. We feel we must ignore data that does not have a p-value of < 0.05. This works when you’re talking about an herbicide, or a nutritional deficiency that we can see and can reverse with fertilizer application, or a pesticide that works to kill a pathogen directly and immediately. We want to play all the notes of that song in the same timing, “1-2-3-4…1-2-3-4”. However, Biologicals are simply more complex than this. When you’re using a product that is effective by influencing dozens of biochemical, genetic, and metabolic pathways in a vastly complicated plant, in a complicated agronomic system, it is very often not so clear-cut.
However, the complexity also lends to the value of these products. The grower still got 10% disease reduction, despite inefficient product application. 10% is a subtle difference, and probably difficult to scout, sure. But it was still there. Imagine if the label advised on the mode of action of the product, and the grower was empowered with all the information he needed. Additionally, what if the grower was able to avoid using his more targeted pesticides, that he is trying to avoid using anyways due to their implications for him with field reintry intervals, preharvest intervals, and minimum residue limits..plus he has seen it become less effective over time with resistance to the pesticide developing. A biopesticide may offer some much-needed complexity. A way to delay using his pesticide until later in the season, or to need fewer applications of it, or to maintain its durability by introducing multiple mode(s) of action into a resistance management program.
I love the nuance, the multiplicity, of biological products. They can work synergistically with the complexity of the plants that we’re growing as crops, to deliver measurable results and alternative solutions to equally complex problems. But we simply can’t research them or use them in the same ways as our more “single” mode of action products. Biologicals exist in the world of Debussy – where complicated timings, unexpected chord progressions, and sometimes other-worldly sounding motifs are what bring their value. Plant gene expression is a tool that we use at Foresight Agronomics to fully dive into this complexity, though there are many useful tools in research that we can also use to dig in.
In a world of stripped-away, black-and-white, quarter-note-on-quarter-note agronomy, let’s consider the opportunities we can grab, the “music” we can make with biological products. Don’t let their complexity scare you away from researching them well and discovering their uses.
