In the production of edible fungi, seed production is a key aspect. In the process of producing strains, improper operation, incomplete disinfection and other reasons can lead to the intrusion of bacteria, contaminated strains, so that the commodity rate of edible fungi decreased, and the benefits of the suburbs decreased. The following describes the common bacteria and control measures for mushroom production.
Penicillium
It is the most common kind of fungus. After the contamination, a small, separate green powdery mildew was present on the medium. The bacteria are extremely widespread and spread by airborne conidia on materials that have not been thoroughly sterilized and wet.
Prevention
(1) Culture materials should be strictly disinfected. (2) Aseptic technique must be strictly controlled when inoculating. (3) Strengthen ventilation, reduce temperature, and reduce humidity. (4) Local contamination can be flushed with 5% to 10% lime water.
Second, Trichoderma
Mainly Trichoderma viride or Trichoderma koningii. Rely on spores floating in the air in organic material cultures such as decayed wood, seeds, plant residues, and compost soils. The fungus is acidic and the temperature reaches 25 to 30°C. When the relative humidity of the air is 80% to 90%, it can easily occur. It can develop from spot to the entire surface in 3 to 5 days. Trichoderma is often mixed with Penicillium. The color of the two mycelium is similar. The difference is that Penicillium is changed from white to green or light yellow, and the Trichoderma mycelia begins to be white, and after green spores become green or copper green, and gradually deepen. Trichoderma viride has strong cellulase activity and can decompose cellulose, which mainly occurs in the interior of sawdust and other lignin fiber-rich culture medium. Because of its rapid growth, in addition to competing for nutrients with edible fungi, it also secretes toxins. Therefore, an "island-like" "antagonism line" that forms a pair of worms is often formed between the edible mycelium to inhibit the growth of edible fungi.
Prevention
(1) Strictly sterilize the culture materials, completely eliminate the mycelium and spores in the culture materials, and perform aseptic operations to enhance ventilation and cooling. (2) Dosage of formaldehyde should not be excessive when disinfected to prevent acidic environment. (3) When there is Trichoderma on the medium, timely apply 75% alcohol, 15% bleach solution, 50% carbendazim 200 times, spray 1% to 5% of lime water or sprinkle white ash powder to remove. After smear with lime water. When handling, it is best to move the strain bag (bottle) outside to prevent the spores from scattering. After the appearance of the trichoderma, it is strictly prohibited to open the bottle cap or uncover the film to avoid spreading. When using plastic bags for seeding, do not move too much during cultivation. (4) Timely removal of germinating species that have not germinated. (5) The tampon of the strainer bottle and strainer bag should not be damp, and the culture room should be kept dry and clean. (6) The mother must be pure. (7) Add 25% (or 5%) of carbendazim 2g or 75% of the carton to 1g per kilogram of dry material.
Third, mucor, to mold and Aspergillus
Mucor, also known as pilose, mainly occurs on the initial culture medium and strains of indoor cultivated mushrooms (ears). The hyphae appeared white or gray at the beginning and turned pale yellow afterwards. The hyphae are sparse, stout, and clearly visible. The larger the moisture content of the culture material, the heavier the occurrence. The ability to break down starch is strong and it grows very quickly. Staggered growth on the material surface, the formation of loose needle-like long hair, about 3 days, can cover the entire material surface, cut off oxygen, compete for nutrients, water, and secrete toxins, affecting the growth of edible fungus mycelium. After about 40 hours, a large amount of black spores can be produced. Rhizopus was similar to Mucor, except that there was no hyphae in the culture material, and only the grapes on the surface of the substrate were grown, and no airborne mycelium was produced. Aspergillus is easy to occur when the moisture content of culture materials is low and the temperature is high. The initial stage of hyphae was white cotton floc, which turned yellow afterwards. When the temperature reached above 27°C, a large amount of spores were produced. Because of different strains, there were black, yellow-green, orange and orange colors, which spread rapidly. Mucor, Rhizopus, and Aspergillus are widely distributed, with spores in soil, fertilizer, and air.
Prevention
(1) Thorough disinfection, sterilization, and aseptic operation. (2) Add 25% (or 50%) of carbendazim 2g, or 75% thiophanate-methyl 1g per kilogram of dried material.
4. Streptomyces
It is also known as Neuromysporium, which can be harmful during the production of strains at all levels. Especially when the temperature is high, the humidity can easily occur. The bacteria are widely distributed in nature, and various organic substances such as corn cobs, corn, cotton seed hulls, and waste cotton are prone to occur. Its conidia are floating everywhere. When it settled on the surface of organic matter, mycelium sprouted quickly. The mycelium spread rapidly, appearing gray or yellow at first, slender, rapidly growing downwards and growing to the tampon. Outside the tampon, a large number of light red, connate, connate spores were formed and clustered to a thickness of 1 cm. It was also referred to as pink powder. Slightly shaken, the spores were scattered into the air and spread everywhere.
Prevention
(1) Do a good job in environmental sanitation and waste cultivation. (2) The culture material is completely sterilized, and the tampon must not be affected by moisture, and it should be replaced immediately after getting wet. The strainer bottle (bag) should be free from damage. (3) The inoculation room must be thoroughly disinfected and strictly abide by the aseptic procedures. (4) Lime on the ground, if necessary, also remove lime from the bottle tampon and keep it dry. (5) After being found, it shall be removed, burned, and sprayed with 75% wettable topbuzzine 500 times solution, or 10 ml formaldehyde per cubic meter of space.
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