What Are These Near My New Grape Vine?

[we5inelgr]

Hi all,

I planted some vines in my backyard about 3-4 weeks ago, and have watered them twice (initially, and just yesterday) with a mycorrhizal product called Great White (http://www.plant-success.com/index.php/mycorrhizal-products/great-white-mycorrhizae.html), to help encourage/establish root growth.

There used to be a small peach tree near where this vine is now planted. The tree was cut down about 4 or 5 years ago and the trunk (about 3&1/2" dia.) and some roots remain.

I've noticed an explosion of mushrooms near that turned up dirt where one of the peach tree roots is, both times I applied the product.

I realize that the mycorrhizal I applied to the soil would encourage fungal growth. I just didn't think about the possibility of it encouraging fungal growth on the surface in the form of mushrooms.

My questions are:

• What kind of mushrooms are those?
• Should I be concerned with those mushrooms near the new grape vines? If so, how should I remove/control their growth?
• Could that Great White product be the source of the mushrooms?
• Or, is it simply feeding the spores/mushrooms already present on the old peach tree roots?

Thanks!

Note: The first three pics are the most recent, taken this morning. First pic is a closeup of the previous round of mushrooms, they are found in the 2nd pic (near bottom) showing both old and new. The bottom two pics are the original mushroom growth noticed about 7-10 days ago after the 1st application of the mycorrhizal product.

[Dave W]

I just did a little checking on the types of mycorrhizal fungi included in Great White. Looks to me like closest thing to a mushroom one may expect from the application of this product would be an underground False Truffle associated with a species of Rhizopogon. The other fungi in the mix seem to also be types that release their spores underground.

The mushrooms seen in the photos appear to be a species of Psathyrella, all of which are saprobes. That is, unlike mycorrhizal fungi which form symbiotic relationships with plants, saprobes feed off dead/decaying vegetable matter. In this case the roots of the peach tree are presumably the host for the fungus producing the mushrooms.

The question about whether the Great White is stimulating the growth of the mushrooms seems like an interesting one to me. Some fungi are suspected to be capable of playing more than one role among the three categories: mycorrhizal symbiot, saprobe, parasite. Is the mushroom --presumably a "saprobic" Psathyrella fungus-- parasitizing some of the mycorrhizae in the Great White? I have no clue about the answer to this question. But if so, then the fungus producing the mushrooms may be consuming the product that you have added to the soil.

Psathyrella mushrooms mainly have very dark purple-brown to almost black spore prints. One species, P. conissans, has a pink spore print. As Psathyrella mushrooms age, the gills generally turn a very dark color. Most Psathyrella mushrooms are composed of fairly fragile context.

[we5inelgr]

Many thanks Dave, for the reply and information. I appreciated it!

I've emailed the company that makes the Great White product, in hopes that they can shed some light on this.

Doing some reading on the Psathyrella mushrooms (http://www.mushroomexpert.com/psathyrella_candolleana.html), it sure does seem like that is what I've got growing.

[we5inelgr]

I just heard back from the company that makes the Great White Product, and here was their response:

The mushrooms very likely are from the Great White. I am not sure what type they are but they are good for the soil and the roots.

[Dave W]

Interesting. The mushrooms do not look like any mycorrhizal species that comes to my mind. So I wonder about exactly what is meant by the sentence, "The mushrooms are very likely from the Great White."