How to Identify Mother Cultures and Spawn of Edible Fungi? A Detailed Guide to the Methods

Shiitake spawn

The mycelium is snow-white, thick and strong, spread out, and uniform, with even margins and a fast growth rate; on the bottle wall it develops in a fan-shaped, feather-like pattern, growing vigorously, and secretes soy-sauce-colored droplets. After the mycelium has fully covered the bottle, within 10 to 15 days an amber-colored transparent liquid is commonly seen, along with the distinctive fragrant aroma of shiitake, with no foul or musty odor.

If the mycelial column inside the bottle pulls away from the bottle wall, this indicates that the substrate moisture is too high; if it has pulled away and the mycelial column also begins to shrink, with the surface mycelial skin thickening and turning dark brown, this indicates that the spawn has begun to age, cannot be stored for long, and should be used immediately.

If small mushroom primordia have already appeared on the surface of the mycelial column, this is one of the characteristics of good spawn, and the primordia should be removed and the spawn used as soon as possible; if a large number of primordia appear, this indicates that the spawn age is greater and it has aged, so it is unsuitable for use.

If wood particles can be seen inside the spawn bottle, the cultivation time was insufficient, and culturing should be continued for a while longer. If the rice bran used is of too poor quality (containing too much husk), causing poor mycelial growth, the medium should be replaced and production restarted.

Straw mushroom spawn

The mycelium is dense, robust, evenly distributed, transparent, glossy, and pale yellowish-white. A large number of yellow-white or rust-red chlamydospore masses indicates normal small-particle straw mushroom spawn; if the chlamydospores are fewer, it is large-particle straw mushroom spawn.

If the mycelium inside the bottle shrinks, withers, and grows feebly, and the medium is dried up or rotted, it is aged spawn and cannot be used.

If the mycelium is snow-white and concentrated, or ink-colored umbrella mushrooms (Coprinus, ink caps) grow inside the bottle, it also cannot be used.

The spawn age of cultivated spawn generally does not exceed 20 days. If mite damage occurs in the spawn, it should be discarded.

Wood ear (black fungus, Auricularia heimuer) spawn

The mycelium is snow-white, like fine wool, with short, even, dense, thick and strong strands that advance evenly all the way to the bottom of the bottle, growing uniformly and consistently from top to bottom, and coming out in a solid block when dug out, not loose.

After the mycelium has fully covered the bottle, brown droplets are generally secreted on the surface of the mycelial mass. Later, pale yellow transparent gelatinous ear primordia appear around the bottle wall and on the surface.

If the mycelial column is tightly pressed against the bottle wall and a small amount of white droplets clings to the inner wall of the bottle, it is fresh spawn. If there is pale yellow accumulated liquid at the bottom of the bottle and the mycelial column has pulled away from the wall and shrunk, it is aged spawn and cannot be used.

Normal spawn has the distinctive fragrant aroma of wood ear; if there is a foul or musty odor, or patches and spherical areas where no mycelium grows, it is bacterial contamination; if other colors such as red, green, yellow, or black appear, it indicates contamination by foreign microbes, and it also cannot be used.

If pale black gelatinous material (ear bases) appears between the medium and the bottle wall, this indicates spawn that is early-maturing or has been subcultured too many times; after cultivation the ear pieces will be small and numerous, difficult to grow large, of poor quality and low yield, and it should be discarded.

If wood particles can be seen inside the bottle but there is very little mycelium, this indicates that the cultivation time was too short and culturing should continue. If after a period of culturing there is no significant change, this indicates that the medium nutrients are insufficient and should be supplemented.

If the spawn grows to about halfway or stops growing at one corner, it may be due to being too dry or too wet. If the mycelium grows evenly and densely, then suddenly becomes sparse with a clear dividing line, this indicates that the upper part of the substrate is properly moistened while the lower part was packed too firmly and too densely.

For spawn grown on wood plugs and twig pieces, both the surface and the interior should be fully covered with white cottony mycelium; if no mycelium is visible after cutting open, this indicates that the wood plugs and twigs are too wet and the mycelial development time was too short, so culturing should continue.

Silver ear (white fungus, Tremella fuciformis) spawn

The Hypoxylon (Xianghui) mycelium is feather-shaped and grows vigorously, evenly distributed and white in the early stage; in the later stage it appears in bundled root-like distributions below the ear base, with many black scar rings on the surface and no other colored spots, indicating that the Hypoxylon fungus is growing well.

The Tremella mycelium penetrates deep into the medium, that is, it "eats" deep into the substrate; there is a thick layer of Tremella mycelium below the ear base, and the sawdust color becomes lighter, indicating strong decomposing ability of the mycelium.

The proportions of Tremella mycelium and Hypoxylon mycelium are moderate, forming large, snow-white white-hair clusters on the surface of the medium. Vigorous growth of the white-hair clusters and a large ear base indicate a young spawn age and strong vitality, suitable for log cultivation; if the white-hair clusters are very small and numerous, or fruiting bodies appear quickly inside the bottle, this indicates too many subculturing times and too great a spawn age; if the white-hair clusters easily gelatinize into small wood ears, this indicates that the spawn is close to physiological maturity, and all of these are suitable for cultivation with substitute materials.

If the Hypoxylon mycelium is sparse and does not penetrate into the substrate, and the fruiting body is gelatinous-mass-shaped or gelatinous-spine-shaped and does not open into a sheet, this indicates that the medium is too wet or packed too firmly. If feather-shaped Hypoxylon mycelium is present but there are no white-hair clusters, then the Tremella yeast-like conidia must be present before it can be used; otherwise it cannot be used. If the mycelium in the upper half of the bottle is sparse or has disappeared, while the mycelium in the lower half grows normally and the ear base turns pale red, producing a large amount of red-brown liquid, it is most likely mite damage. If white flocculent mycelial film is found, it is contamination by foreign microbes, and in all cases it cannot be used.

Button mushroom (Agaricus bisporus) spawn

The mycelium of superior button mushroom spawn is grayish-white, dense, fluffy, and finely downy, growing uniformly and consistently from top to bottom and inside to outside, resistant to high temperatures and to pests, diseases, and foreign microbes, quick to colonize the substrate, and free of fan-shaped variation. The mycelium of creeping-type spawn is distributed in a fine downy form, with no yellow-white mycelial covering.

Mycelium in the substrate that is in thick cord-like or thin thread-like form and pale yellow. Mycelium that is shriveled and shrunken, growing feebly, or with a very thick yellow-white mycelial covering above, is aged spawn.

Spawn showing green, yellow, black, or orange-red contaminant spores must be discarded and burned. If the mycelium in the upper part of the medium is shriveled and deteriorated while the mycelium in the lower part grows well, this indicates that the medium is too dry and the cultivation temperature is too high. If almost no mycelium can be seen in the substrate and the contents are mushy, this indicates that the moisture is too high and the spawn is too old, and it cannot be used.

Lion's mane mushroom (Hericium erinaceus) spawn

Superior lion's mane mushroom spawn has snow-white, dense, thick and strong mycelium that grows uniformly and consistently from top to bottom and inside to outside. It readily forms fruiting bodies on the substrate.

If the mycelium shrinks or yellow slime accumulates at the bottom of the bottle, it is aged spawn and cannot be used. Slow, feeble, and fine mycelial growth may be due to insufficient acidity of the substrate or insufficient organic nitrogen; the amount of bran or fine rice bran in the substrate should be increased to improve the nutritional conditions of the spawn. Spawn contaminated by foreign microbes cannot be used.

Oyster mushroom (Pleurotus ostreatus) spawn

Superior oyster mushroom spawn has snow-white, thick and strong, dense mycelium that grows uniformly and neatly in a coarse wool-like form, with strong wall-climbing ability. After about half a month of culturing, a small number of coral-like small primordia or white primordia can form on the inner bottle wall.

Most varieties form fluffy aerial mycelium on the upper surface of the medium; low-temperature varieties often secrete yellow-brown pigment from the aerial mycelium, and especially in high-temperature seasons, low-temperature varieties often show red-brown or yellow-brown aerial mycelium or yellow liquid, which is a normal phenomenon.

If a large number of coral-like fruiting bodies appear above the medium or fruiting bodies grow out from the gap in the bottle cap, this indicates that the spawn age is too great and it should be used as soon as possible. If the medium shrinks and yellow liquid accumulates at the bottom of the bottle, it is aged spawn and cannot be used. If the mycelium in the upper part is sparse, dull, feeble, and shriveled while the mycelium in the lower part is normal, this indicates that the initial cultivation temperature was too high, ventilation was poor, or there was bacterial contamination. If yellow, green, or orange-red appears, it indicates contamination by Penicillium, Trichoderma, and Neurospora, and it must be discarded. If the mycelium grows about halfway in the bottle and no longer grows downward, this indicates that the medium is too dry, too wet, or too firmly packed; the normal mycelium from the upper part can be used, and culturing should not continue.

Enoki mushroom (Flammulina filiformis) spawn

The mycelium is flocculent, snow-white, dense, robust, and elastic. Powdery oidia sometimes visible on the surface indicate superior spawn. If a tough mycelial film appears, it can still be used as long as the film is removed. If the spawn dries up, the mycelial column contracts, or the mycelium self-digests and produces a large amount of red-brown liquid, this indicates that the spawn has weak vitality; if yellow appears, this indicates that the spawn has aged.