What is the Neurospora disease of reishi mushrooms?
Neurospora, also known as bead mold, chain mold, and red bread mold. It belongs to the subdivision Ascomycotina, class Ascomycetes, order Sordariales, family Sordariaceae. Its asexual generation belongs to the subdivision Deuteromycotina, class Hyphomycetes, order Moniliales, family Moniliaceae, genus Monilia. The main harmful species is Neurospora sitophila Shear et Dodge.
1. Morphological characteristics: The ascocarps of the sexual stage grow in clusters or scattered on the surface or inner layer of the substrate. Mature ascocarps are dark brown, pear-shaped or oval, with a papillate ostiole. The ascocarps contain multiple asci but no paraphyses; the asci are cylindrical with short stalks, and one ascus generally contains 8 ascospores, with every 4 forming one mating system. The ascospores are initially colorless and transparent, and at maturity change from olive color to pale green, with protrusions and nerve-like longitudinal ribs on the outer wall, hence the name Neurospora.
The chain mold of the asexual stage is usually in the form of a faint white powdery mold, with septate, branched, net-like hyphae. The conidiogenous hyphae branch dichotomously, and the conidiophores are relatively short, growing directly from the hyphae; the conidia are produced in chains, single-celled, easily detached, oval, red and orange-red.
2. Occurrence pattern
(1) Transmission route: spread by airflow and wind. Unsanitary sites, poor aseptic conditions, incomplete sterilization, damp or too loose cotton plugs, and sand holes in mushroom bags are the main routes of primary infection by Neurospora. Once infected, the new conidia produced are the route of secondary infection.
(2) Occurrence conditions: This fungus has extremely strong vitality, the conidia can withstand high temperatures, the hyphae are aerobic, and it can grow within 4-44°C, growing fastest at 25-36°C. It grows rapidly when the water content of the culture material is 53%-67%, and it can grow at pH 3-9. The hot season is the peak period for the occurrence of this fungus.
3. Damage symptoms: A fluffy mold layer, namely a spore mass, rapidly forms on the surface of the material or on the cotton plug, and can contaminate the entire culture room within 1-2 days. It has extremely strong vitality and can break through plastic bags to grow outward, causing the entire spawn production and cultivation to fail.
4. Control methods
(1) The culture material must be fresh, without caking or mold, exposed to the sun before use, sterilized thoroughly, and the cotton plug must be prevented from getting wet.
(2) Spray the culture site, bed frames, walls, etc. with a 500-fold dilution of 70% thiophanate-methyl solution.
(3) For slight infection of the cotton plug, under aseptic conditions, sterilize the bottle mouth and cotton plug by burning with a flame, dip the cotton plug in lime powder and put it back in place; if the cultivation bag is contaminated but the vitality of the reishi mushroom hyphae is still very strong, dig soil 30-40 cm under the shade of trees, arrange the mushroom bags in it, cover with moist soil, and the Neurospora will disappear in about half a month; if the contamination is severe, it should be removed promptly and burned or buried deep to prevent the conidia from spreading and infecting again.