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  • From: Thomas Olenio <tolenio@sentex.net>
  • To: <nafex@yahoogroups.com>
  • Subject: [nafex] Re: Apple and mycorrhizal fungi
  • Date: Thu, 6 Dec 2001 14:57:02 -0500 (EST)

Hi,

Here is the response from "Plant Health Care" regarding my myco.
questions.

Tom

--


On Thu, 6 Dec 2001, Mike Kernan wrote:

> I have read your questions. There may be some mistaken assumptions about
> the nature of the mycorrhizal association. Your questions suggest a
> mistaken understanding that the non-inoculated trees and plants were not
> associated with mycorrhizal fungi, and therefore, the differences between
> the treated and untreated trees or plants could be attributed to the
> presence of mycorrhizal fungi in one group, and its absence in the other.
> In fact, all trees and almost all plants growing in the field are
> mycorrhizal, whether you inoculate them or not. If planted in the field
> rather than in a controlled greenhouse setting, it is nearly impossible to
> prevent native species of mycorrhizal fungi from colonizing the root
> system. Therefore, I am confident that all the apple trees in your example
> were colonized by mycorrhizal fungi of one kind or another, whether or not
> the trees were in the inoculated group or the uninoculated group. You do
> not mention whether root samples were taken before and after the treatments
> to determine to what extent the roots were colonized by mycorrhizal fungi.
> There are cultural practices that can mask the beneficial effect of the
> mycorrhizal association. Mycorrhizal fungi improve the ability of plants
> to absorb water and mineral nutrients. The effect of this is most striking
> when a plant is stressed under situations of drought or nutrient
> deficiencies in the soil. In such cases, the mycorrhizal plants perform
> dramatically better, and are far more productive. However, when working
> with nursery plants, the benefits are not so apparent. Here, the plants
> are protected from drought (by irrigation) and from infertile soil, (by
> fertilization). So protection against stress is not apparent when there is
> no stress.
> Inoculated plants typically do not display their value in the nursery.
> Rather, the value of the fungi becomes more apparent when they are
> outplanted to a site where they are left to the whims of nature (more or
> less). In an orchard setting, the grower might recover benefits in the
> reduced need for fertilizer, and better resistance to drought (if his
> irrigation fails). Sometimes, the fungi can reverse the effects of
> certain nutrient deficiencies that the grower has failed to address in his
> cultural program. They can also rejuvenate trees in decline. These are
> all within the scope of mycorrhizal fungi. That is not to say that these
> things will always be achieved by inoculation.
> I do not know why the inoculated trees in your example reportedly grew
> slower. Apples are ednomycorrhizal trees, and associate only with VA
> endomycorrhizal fungi. Were the species of fungi applied to these trees
> endomycorrhizal fungi?
>
> What were the ingredients of the inoculant used? Was it merely a
> mycorrhizal inoculant, or did it contain other ingredients that effect
> plant growth or soil fertility? Did the manufacturer have adequate QC to
> ensure that the intended organisms were actually present, that they
> remained alive when exposed to the conditions of mixing, packaging,
> handling and storage, and were the products used appropriately and within
> the limit of the shelf life? The above question that I ask all stem from
> my experience with products produced (or should I say "packaged") by other
> companies. Most companies that sell mycorrhizal products are selling
> copycat formulations. The companies buy what is purported to be a spore
> mix and/or mix of root fragments, and they add it to their own formulation,
> and sell it as a mycorrhizal inoculant, making all the claims that they
> copied from Plant Health Care's labels. A closer look at such operations
> reveals many lethal mistakes:
> (1) Many companies fail to realize that living fungi cannot be treated the
> same as a nonliving ingredient (lest you kill them). They do not recognize
> that heat, pressure, and extremes encountered in storage (including aging)
> can kill the spores and root fragments.
> (2) Many of these companies never considered the fact that you must test
> your other ingredients to make sure that they do not kill, desiccate, or
> inhibit the fungi. They just mix them together, slap on a label, and off
> it goes.
> (3) Many of these companies have no biologists on staff, or certainly not a
> fungal biologist skilled in mycorrhizal fungi. The most basic aspects of
> handling living things are ignored.
> So when you attribute the problems that your report encounters to the
> mycorrhizal condition, were all of these things considered? In fact, a
> trial like that must involve stringent controls and good experimental
> design. Otherwise you may be observing effects not planned for, and your
> conclusions may be quite erroneous.
> Regards,
>
> Michael J. Kernan, Ph.D.
> Technical Services
> Plant Health Care, Inc.
> 440 William Pitt Way
> Pittsburgh, PA 15238
> Tel: (800) 421-9051, x103
>
>


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