Maintenance of pure mycelial cultures is a necessity fo ultimate spawn preparation and spawn production. Once a culture is obtained, it is advisable to take note of the appearance of the mycelium, to observe the normal growth patterns of the specific lines. These observations are important to do, so that one will be aware of even the subtlest change that may lead to deleterious effects.
A desirable mycelial culture is one that is pure, free of contaminants and of sectoring of other abnormalities. Contaminants include other fungi, bacteria, or insects growing on or infesting the culture media along with the desired mycelial culture. When a culture is first obtained, by whatever means, it should be transferred several times to fresh media, to observe for any from of contamination.
Sectoring is any type of mycelial growth that differs in appearance, growth rate, color, or otherwise from the typical appearance of a given strain. Sectoring is often observed as a more rapidly growing area near the leading edge of growth, exhibiting a different growth habit from the rest of the culture. Other abnormalities that might appear in a culture are fluffy, aerial mycelium, thick or rubbery textures, of color changes such as browning or darkening of the mycelium. Sectors of other change in vegetative growth could affect the productivity of the culture. Therefore, it is very important to recognize and avoid propagation of abnormal mycelium to agar and further spawn production.