Nano Particle Technology

Copyright 2017 by Scot G. Patterson. All rights reserved.

Smaller Is Better

Our pesticides use nano particle technology to encapsulate the active ingredients (terpenes) found in essential plant oils. The reason is simple – smaller particles penetrate plant and insect tissue better and the finer spray covers the leaf surface more evenly and efficiently. Another important benefit is that the nano particle emulsions are thermodynamically stable, which means they don’t separate or require shaking before use. We have spent more than five years reviewing research literature and conducting laboratory experiments to develop state-of-the-art formulas for our pesticides. One of our first nanotechnology formulas was tested in 2015 at the University of Oregon’s Nanoparticle Lab using Dynamic Light Scattering. The results confirmed a particle size of 32 nanometers. This is well within the nanometer range, which begins at 100 nanometers or smaller. For those of you unfamiliar with this scale, it is the size of 160 carbon atoms sitting side-by-side. Picture 1.1 shows the sample two years later.  After improving the formula for several years, the most recent DLS data (December 2019) for Peppermint Fury show a particle size of 9 nanometers.

Picture 1.1 Formula 3.7 NanoEmulsion After Two Years

The Difference is Clear

Nanotechnology oil-in-water mixtures are clear or translucent because the particles are so small that they don’t interfere with light passing through the solution. This provides a very useful index for our experimental work in the lab because we can evaluate the outcome by its clarity. Picture 1.2 shows several different nanotechnology formulations of essential oils.

Picture 1.2 Three Typical NanoTechnology Formulations

With clarity in mind, it is apparent that our competition is using out-of-date technology.  Their formulas are cloudy and require constant agitation to stay mixed.  Their products are oil/water mixtures with much larger particles and that require the use of a lot of additional components to keep everything (poorly) in solution. And therein lies the problem – the additional chemistry can be toxic to plant tissue. These relatively crude formulas need constant shaking to keep them evenly mixed.  If these products separate while they are being applied, most of the plants will get very little active ingredient and the last plants sprayed will get most of it, resulting in damaged plants and uncontrolled pests.

Test Results

We thought we would discuss the test results from the Nanoparticle Lab for all the nerds out there. You may need some help to decipher the data presented in Figure 1.1 – I certainly did!   Notice that the data from the ten acquisitions are perfectly aligned and that the abrupt drop-off in the curve.  This shows that the majority of the particles are of the same size (this is called polydispersity). This result is important because it shows that the formula components are in the correct proportion. All of the ingredients have been incorporated into micelles (a specific type of nano particle), which is exactly what we want. Extraneous chemicals increase the risk of toxicity to plant tissue.

Figure 1.1 DLS Analysis of Formula 3.7 (shown in Picture 1.1)

Developing Effective Formulas

After this first success, we spent the next six months creating and refining stable emulsions for each of nine different essential plant oils that can be used in minimum-risk pesticides (EPA 25B). We focused on the oils that the research literature indicated had potential as natural pesticides: cinnamon, clove bud, lemon grass, mint, peppermint, rosemary, soy bean, thyme, and wintergreen. At GardenCare Naturals, we use steam-distilled, organic plant essential oils from verified sources.

With an arsenal of emulsified oils in hand, we tested each of them on infected plants. We tried different plants: several different strains of marijuana, roses, rhododendrons, and peppers. We used them on a variety of common garden pests: two spotted spider mites, cyclamen mites, broad mites, russet mites, aphids, white flies, and powdery mildew with some surprising results. Some of the oils most commonly used in natural pesticides were ineffective or toxic to plant tissue, while others that are not often used were very effective and plant friendly. As our own research proceeded, it became increasingly clear that our competitors haven’t done their homework. Instead of advancing our knowledge base, they simply scratched the surface and copied each other. Many of them are using three or more essential oils in their pesticides assuming there is a synergistic effect from doing so. The research literature does not support this assumption. It turns out that the interaction is complex and can be synergistic or antagonistic. The other problem with using mixtures of oils is that it reduces the concentration of any one oil and its terpene constituents to the point that none of them have much effect.

Assessing the synergy or antagonism of oil mixtures is a work in progress at GardenCare Naturals. The total volume of essential oils tends to remain the same (around .5% v/v) but the sheer number of possible mixtures at various concentrations increases exponentially as more ingredients are combined. Because of the vast number of experiments required, testing mixtures for improved outcomes is a never-ending process.