Mycorrhizae and fungi products comparision

MOSHAV MAZOR, Israel, November 27, 2017 /PRNewswire/ --
Groundwork BioAg, Ltd. is pleased to announce that its Rootella™ series of mycorrhizal inoculants has been allowed for use as inputs in organic agriculture, by both OMRI and Ecocert certification agencies.

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Quantifying Mycorrhizae: Spores vs. Propagules and Why it Matters.

Published on March 6, 2017
Mike Mason, JD/MBA, Co-Founder at Mycointech

When examining the labels of various commercially available mycorrhizal products, you may have noticed that some labels read in terms of “propagules,” or “props”, and some are in “spores.” You have probably asked yourself “what is the difference and what do all these numbers mean?”

In order to understand the differences, we first need to define some terms. A “propagule” is defined as any part of the plant or living organism that is used for propagation. In terms of mycorrhizal fungi, there are three types of structures that do this job—spores, mycelium/vesicles, and colonized root pieces. Thus, there are different types of propagules. Let's take a look at them up close under a microscope:

Spores

Mycelium

Colonized Root Pieces

Spores are the natural highly-resistant part of the fungus, adapted for survival and can live for years without plant roots due to the exterior “shell” that surrounds it. The shelf life of spores is much longer than that of mycelium or colonized root pieces. Spores are also more resistant to environmental conditions like temperature and moisture, pressure, etc. This is critical to understand when applying mycorrhizal fungi, for example, through irrigation. In an irrigation application, where the delicate mycelium can be damaged by going through an irrigation system, you’d want to apply more spores than mycelium.

Mycelium and colonized root pieces are both part of the living mycorrhizal fungus. They are adept at quickly colonizing a plant (thus making the host plant mycorrhizal) but are sensitive to things like moisture and temperature. However, colonized root pieces may contain spores and thus be viable for a longer period of time. Unlike spores, mycelium need plant roots to live, thus making their shelf lives much shorter than spores.

So in other words, a propagule is a classification that encompasses spores, mycelium and root pieces. Example: Spores are necessarily propagules, but propagules are not necessarily spores (because they could be root pieces or mycelium). Let’s look at a diagram:

Why does this matter?

We at Mycointech, prefer a spore-count based quality-control test for inoculum. If you were to count all the three different types of propagules, the total number would be higher, however because the shelf life of the mycelium and/or root pieces can be very short, it’s hard to get an accurate count and guarantee a 2-year shelf life. This higher number helps for marketing purposes but not for the effectiveness of the product. Also, with propagule-count based inoculum, you have to keep in mind that 50% of the quality of the mycorrhizal fungi can be expired or have lost a portion of its efficacy, due to the short life of the mycelium.

In our experience and lab data, the ratio of spores to propagules for an in-vivo produced inoculum is between 1:2 and 1:4. If we assume a ratio of 1:3, since our company is only counting the spores, we are really only counting 1/3 of the total propagules. Let’s compare two examples:

1) Label 1 reads 100 props per gram. That means in every gram of product, for example, there could be an average of 30 spores, 30 mycelium and 40 root pieces.

2) Label 2 reads 100 spores per gram. This means in every gram of product there are at least 100 spores, plus the uncounted mycelium and root pieces. Spores represent 1/3-1/4 of the total prop count. Using that benchmark, a 100 spore per gram product would be equal to that of a 300-400 propagule product.

We quantify and price our mycorrhizal inoculum based on spores, however we include mycelium and root pieces in all of our material. This is helpful so you can guarantee at least a 2-year shelf life with your product (because of the spores) but can also have the added benefit of the colonizing properties of the root pieces and mycelium. With our inoculum, not only are you better able to gauge the quality of the inoculum and guarantee with certainty your product’s shelf life, you are also getting 2/3 of the propagules for free.

Spore-count based inoculum is also helpful for registration purposes. For some states and regulatory agencies, having testing that shows a product doesn’t contain what its label says it does can mean a stiff penalty. If your label reads in propagules and your product sits on the shelf for a few months, as we know, its efficacy will be likely be decreased due to the short life of mycelium and colonized root pieces. However, if you are buying a product quantified in spores, you know with confidence that your inoculum will have what your label reads, even after a couple of years.

All three types of propagules have their strengths and each has its weakness. A complete mycorrhizal product will contain all three. However, for commercial products and for registration purposes, we believe spores are the best metric by which to measure and sell mycorrhizal fungi. Mycointech includes all three types of propagules in its products and can change the proportions of propagules based on the desired application.

A mycorrhizal inoculum can contain many propagules, but how do we know that they are all viable? How do you measure that? We will discuss this in an upcoming article. The bottom line is you need to do some due diligence when buying a mycorrhizal product. Make sure that you are getting the inoculum at the best price-point. Take a good look at the labels and look at how much mycorrhizal fungi you are actually buying. For more information, or to have a product customized to your specifications, send us an email at sales@mycointech.com or visit our website at https://www.mycointech.com/

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