Mushroom Mycelium

Germination of spores and isolation of pure mushroom mycelium. 

Mushroom spawn is used to inoculate prepared substrates. This inoculum consists of a carrier material fully colonized by mushroom mycelium. The type of carrier varies according to the mushroom species cultivated, although rye grain is the choice of most spavwi makers. The history of the development of mushroom spawn ior Agaricus brunnescens culture illustrates how spawn production has progressed in the last hundred years. 

Not all discolorations of the grain are de facto contaminants. Mushroom mycelium exudes a yellowish liquid metabolite that collects as droplets around the myceliated kernels of grain. As the culture ages and the kernels are digested, more metabolic wastes are secreted. Although this secre-... 

The purpose of composting is to prepare a nutritious medium of such characteristics that the growth of mushroom mycelium is promoted to The practical exclusion of competitor organisms. Speoifically this means ... 

To create a selective substrate, one in whioh the mushroom mycelium thrives better than competitor mioroorganisms. 

Once the primary bed has been established outdoors, it can be likened To a perennial plant, which is the nature of mushroom mycelium. Indoor spawn preparation and incubation become unnecessary. With each successive year chips can be drawn from the original bed and used as inoculum. This means that the total bed area can be multiplied by five on an annual basis. (See Figure 164 of Psilocybe cyanescens fruiting indoors in tray of alder chips). 

The inoculation of compost or bulk substrates is called spawning. The colonization of these substrates by the mushroom mycelium is known as spawn running. At spawning and during spawn running there are several factors that must be considered if yields are to be maximized. These factors are ... 

Since mushroom mycelium grows within the substrate, the substrate temperature must be monitored closely. Thermometers are placed both in the center of the substrate—the hottest region —and in the room s atmosphere. These two thermometers establish a temperature differential. Ifthe hottest point in the substrate is 80 ° F. and the air is 70 ° F. then the temperature of the total mass must lie within this range. 

Mushroom mycelium is extremely sensitive to dry air. Although a fully colonized substrate is primarily protected from dehydration by its container (the tray, jar or plastic bag), the cropping surface remains exposed. Should the exposed surface dry out, the mycelium dies and forms a hardened mat of cells. By covering the surface with a moist casing layer, the mycelium is protected from the damaging effects of drying. Moisture loss from the substrate is also reduced. 

The casing is a layer of material in which the mushroom mycelium can develop an extensive, healthy network. The mycelium within the casing zone becomes a platform that supports formation of primordia and their consequent growth into mushrooms. It is the moist humid microclimate in the casing that sustains and nurtures mycelial growth and primordia formation. 

During the pin initiation period fresh air is introduced into the room to remove metabolio gases produced by the mushroom mycelium. Although gas production is reduced once this vegetative... 

Figure 174 Penicillium mold near to transferred wedge of mushroom mycelium.

Macroscopic Appearance A rapidly growing rich gray black to blackish mycelium. Alternaria first appears as scattered blackish spots in the spawn jars, soon spreading and overwhelming The mushroom mycelium. On agar, it resembles a black Penicillium- ke mold. 

Figure 208 Monilia-Wke mold on agar media with mushroom mycelium.

Macroscopic Appearance Typicalfy appearing as a fast growing whitish mycelium, fine and or cottony in its growth. Species of Mycelia Sterilia closely resemble mushroom mycelium and may be mistaken for it. Sometimes they form whitish to blackish aggregates of hyphae that are sclerotia-like. 

Comments Papulospora is competitive to mushroom mycelium and can therefore postpone or inhibit fruiting. Papulospora byssina Hotson is the brown plaster mold commonly encountered in mushroom cultivation. Colonies of this contaminant can grow up to several feet in diameter if cor-... 

Penicillium sometimes contaminates poorly prepared compost or spawned compost that has undergone secondary heating. Here, grain kernels formerly colonized by mushroom mycelium become susceptible to weed molds such as Penicillium and Doratomyces and then spread onto the compost and/or casing soil. 

The growing room and all containers should be washed and disinfected between crops. Wood in particular harbors contaminants, including virus infected mushroom mycelium. Treatment of wood with cuprinol or copper sulfate is common. Petroleum based products should be avoided. 

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