Fungi are one of the most successful biological plant species. Many companies are engaged in breeding oyster mushrooms. This species is prone to attack by bacteriosis, harmful insects and a number of diseases.

Insect pests

Tick ​​larvae

Woodlice

Midge

This pest is a problem for absolutely all mushroom farms. It is almost impossible to remove midges without harm. Most experienced mushroom growers recommend destroying midge-infested blocks. Next, you will need to disinfect the room with chemicals. In the future, it is necessary to keep the mushroom room clean. It is also recommended to make a mesh on all ventilation holes. Once every six months or a year, spray the room with a 2-4% solution of bleach, and it is necessary to close the room for a couple of days.

It is unsafe to treat a midge-infested plantation with insecticides. Some of the chemicals remain in the mushrooms in any case. In addition, they significantly inhibit the growth of mycelium and have a detrimental effect on yield.

Oyster mushroom diseases

The most common fruit disease is green mold. Because of it, the mycelium grows slowly or dies. What is the reason for the spread of the disease? One of the main reasons is excess substrate temperature. Another important cause of the disease is an increase in the percentage of nitrogen supplements.

Green mold can lead to stunted mycelial growth.

The delay in the onset of fruiting is a consequence of green mold. It may cause staff allergies. Mold owes its appearance to fungi of the genus Trichoderma. The toxic green color of the colony comes from the mold spores themselves.

Oyster mushroom diseases photo

Trichoderma enzymes destroy oyster mushroom mycelium. During the early stage, the white form of the aggressor is practically indistinguishable from the fetal primordium. This disease can be dealt with in different ways. Foundationazole should be added to mushrooms (no more than 0.2 kg per 1 ton). If they become moldy, then the first symptom of the disease occurs.

The pathogenic fungus dactylium causes the appearance of cobweb mold, which can change the very shape of the fruit.

All imperfect mushrooms are competitors of oyster mushrooms. They similarly search for power sources. The reason for the spread of this disease is non-compliance with sanitary and hygienic standards.

Hairy mold is another oyster mushroom competitor looking for food sources. The disease develops due to a violation of temperature norms during the incubation stage.

Orange mold prevents the mycelium of the product from developing. In some cases, the cause of spread is the use of contaminated material during planting.

Brown mold similarly competes with fungi for food sources. Because of this, the onset of fruiting may be delayed. There is a possibility that some workers will experience an allergic reaction. This disease occurs when the percentage of nitrogen content is exceeded.

For preventive purposes, pasteurization must be carried out. It is important to evenly moisten the substrate.

1.The block contains brown smudges from slots, spots of ungrowth appear in the bottom corners, and excess water accumulates. An unpleasant odor may appear, sometimes there is an odor of ammonia.

This is due to waterlogging of the substrate. Excess moisture contributes to the rapid spread of various bacterial infections and the development of mold. With the accumulation of pathogenic microflora, the already whitened block may begin to become covered with yellow spots on days 11-13, and after 3-4 days it may completely die.

2. The blocks overgrow very quickly, have a beautiful, uniform white color, and the primordia begin to bear fruit together. But then some of the primordia begin to dry out, and a large number of drusen wither in the early stages of fungal development.

The second wave gives a very low yield or does not form at all.
Such problems are observed when the substrate moisture is insufficient, because mushrooms cannot sufficiently absorb nutrients due to lack of moisture. On the dead remnants of drusen, moisture begins to accumulate and a secondary bacterial infection develops, so they look like they are soaked and not dried out.

3. Mold in the block - green (Trichoderma) or black (Mukor).
If the block is overgrown unevenly, then a grayish-white coating of mold mycelium may appear on the unovergrown spots, which at first is practically indistinguishable from oyster mushroom mycelium. 3-5 days after it appears, it forms spores and the stain turns green, olive or black, depending on the type of mold.

This is due to the low pH of the substrate. The optimal pH level is considered to be in the range of 7.5-8.5. Achieved by adding lime when preparing the substrate. Oyster mushroom mycelium develops well in this range, and molds prefer acidified substrates. Violations of the sanitary regime of inoculation treatment and the regulations for inoculation of blocks also contribute to infection, due to the entry of mold spores into the substrate from the air.

Sometimes the oyster mushroom block turns green completely in the early stages of incubation and dies. Very rarely, pink or orange mold (neurospora) appears in the bag.

As a rule, these two facts are associated with poor-quality heat treatment of raw materials. Read about hydrothermal regimes, and here about. Some mushroom growers conduct experiments and, as a result, prepare the substrate incorrectly. For example, additives that have not undergone heat treatment (not calcined) are added on the inoculation table: bran, chalk, gypsum. In this case, the additives themselves can be a source of Trichoderma spores, and the block is first covered with small spots of greenery, and then may completely disappear (due to numerous points of spore growth).

The enterprise needs to develop technological regulations that establish the sequence of all technological operations, indicating temperature and time parameters, and be sure to follow them. Ignorance of the microbiological processes occurring during the preparation of the substrate sometimes leads to ignoring important components of this technological process or simplifying it (for example, non-compliance with temperature parameters, reducing the time of one of the stages, incorrectly selected cooling modes during pasteurization).

It is necessary to record in a separate journal the change in any clause of the regulations, indicating the date (batch number), for further analysis of the situation. Some problems with substrate overgrowing may be due to the fact that the equipment does not comply with the selected modes and cannot ensure high-quality implementation of this process.

If there are violations in the processing of plant raw materials, the yield of the fungus may be low, despite high-quality mycelium and a properly planned microclimate in the growing chambers.

Problems associated with violations of climatic and sanitary parameters of incubation.

1. The appearance of green mold in the slots of blocks when overgrown

2. Subfilm condensate

May occur due to:

— waterlogging of the substrate,

- a sharp change in temperature in the room where the blocks are overgrown.

Both of these reasons can cause the proliferation of bacteria and Trichoderma spores in the subfilm layer. Then, between the inner surface of the film and the overgrown substrate, either saucers of brown, foul-smelling liquid (first and second photos above) or green spots of trichoderma (third photo) appear. If these two reasons are present simultaneously, then the blocks are almost 100% defective.

Indeed, due to the presence of water in this layer, gas exchange is disrupted and the mycelium hyphae cannot grow there, but mold and bacteria spores feel great there, and can grow in three to four days so that they form a completely green crust under the film or solid yellow -brown stain of bacterial slurry.

Unfortunately, in this case, the entire block may be white, beautifully overgrown at the break, but not bear fruit at all.

3. The surface of the bags under the film becomes covered with pronounced compactions - white spots.

4. Primordia on mushroom blocks form (form) and grow under the film directly near the perforations or in the subfilm space, regardless of the perforations.

5. Abnormal development of primordia, presence of “bumps”
Indicates fluctuations in temperature and humidity during incubation.

I decided that sometimes I need to write down problems that arise and their causes (and, preferably, solutions).
Here's an example: some mushrooms have growths on their caps.
These are essentially new mushrooms. :) During the fruiting period, no matter how hard you try to remove the mushrooms until they are fully ripe, there are still spores in the air (that’s why workers in the cells need to use respirators! The spores cause a strong allergic reaction).
Spores that fall on mushrooms sense the nutrient medium. After all, the mushroom is as nutritious for them as straw. And with a sharp change in temperature, they immediately begin to grow.
The strong cold snap outside (from -4 to -31 overnight) also affected the temperature in the supply air and, consequently, in the cells. The temperature in the chamber jumped by several degrees and the mushroom managed to react, although the automation quickly corrected the climate.
As a result, the phenomenon is not widespread, but one and a half percent of the mushroom from one wave came with growths. You can eat these mushrooms; they are no different from the others. But their appearance is no longer marketable; you cannot explain the nature of the phenomenon to all buyers. That’s why the workers stole such a mushroom from their homes and will eat it themselves.

We encountered another phenomenon with a similar nature. One store sent a photo of our mushroom with the comment “It’s moldy!”
The mold on mushrooms is green or black, and here there is white fluff (below in the photo). These are also germinating spores and also due to non-compliance with the temperature regime.
When we collect a mushroom, it gradually goes through stages from 15 degrees to 3 degrees (not sharply, not shockingly!). We also monitor the temperature when sending. In severe frosts, we warm up the van booth before loading the mushroom, for example. In general, the mushroom is kept at the same temperature all the time.
But it seems that in that store the mushroom was not immediately put in the refrigerator, but kept warm for several hours (the spores came to life) and then put in the refrigerator (the spores began to grow).
In general, it is also edible and also non-commercial.

This is the most common type of marriage. Most often occurs with hydrothermia and improperly performed xerothermia.
It is difficult to distinguish oyster mushroom mycelium from mold in the first stages of growth, since most of them have the same white mycelium. And only the spores are multi-colored, and it takes time for them to mature.
Most often, various types of trichoderma settle in the overgrown substrate; mushroom pickers call it brilliant green. Green spots of all colors appear in the bags, from olive to gray-green. If the speck is small, then the oyster mushroom hyphae eat it, and fruiting subsequently proceeds normally. Large spots of ungrowth in the substrate block, on the contrary, progress and suppress the development of oyster mushrooms.

Many are surprised that the mushroom block turned green on the 12th or even 15th day. And before that it was white, everything was fine. In fact, the fungus has been mature for a long time - since the briquettes began to overgrow. Trichoderma hyphae are white, with a grayish tint. And when the Trichoderma mycelium has matured, we see green accumulations of its spores.
It is very rare to find orange, red or pink mold - this is Neurospora. Read where it comes from

Neurospora multiplies very quickly and can infect the entire incubator in a matter of days. If you find an orange substance in a bag, especially one coming out of a slit, seal the slit and take the bag away from the enterprise. Free it from the film, bury it, and burn the polyethylene. Be sure to treat the room with chemicals such as Armex and Virocide. Do not wait until the incubator is free - you risk losing everything that is there. If there are already overgrown batches in it, take them into the growing chamber. Ungrown ones can be treated, being careful not to get the product on them.

It happens that a gray or black coating forms in the briquette. And what it’s called is impossible to determine without analysis and a microscope. In general, the name of the mold doesn’t really matter. It is important to understand that putrefactive fungi of any color indicate problems in production.

How to deal with mold in mushroom blocks.

Beginners think that there are chemical preparations to combat Trichoderma in mushroom blocks. If the defect occurs as a result of improper steaming or poor quality of raw materials, then chemistry will not help. The mycelium of brilliant green, like oyster mushrooms, is killed by one type of reagent - they are called fungicides. And you won’t be able to add them to the plant mass. They treat the premises.

To get rid of a problem, you need to know its cause. There are three main ones, I will list them starting from the most common:

1. Poor quality heat treatment of raw materials.

If brilliant green penetrates deep into the entire mass, this means that the processing technology in terms of time and temperature was violated, or the substrate has high humidity or pH (pH) below 7mi.

The faster mold invades a briquette containing processed raw materials, the greater the deviations from the technological processing regulations.

The most critical case is when overgrowth is not observed at all, and the grains of oyster mushroom mycelium are covered with a gray-green coating.
As a rule, the quality of the mycelium has nothing to do with it - it’s just that, first of all, the fungus begins to occupy the boiled grain, there is easily digestible nutrition there. And then he switches to husks or straw that are poorer in nitrogen.

What should be done.

Change the regulations for processing plant raw materials. Read more ;
- measure the pH of the substrate, maintain it at an optimal level of 7.8-8.5. The growth of mold mycelium is inhibited at a pH above 8, but oyster mushrooms can still withstand this range. Although, at a pH above 9, inhibition of its growth begins;
- Keep the sowing room clean, create excess pressure there, so that spores of harmful microorganisms will not get into the processed raw materials on the sowing table.

2. Disturbance of the microclimate during incubation

More often it leads to infection only in the subfilm layer.
Incorrectly designed ventilation, temperature fluctuations in the chamber, create a large temperature difference between the subfilm layer and the internal contents of the bag, which causes an outflow of water from the center to the subfilm. The presence of free water between polyethylene and the substrate leads to increased growth of mold and/or bacteria.

Although, when breaking apart an overgrown monolith, it is clear that the entire thickness of the substrate is overgrown evenly and does not contain Trichoderma inclusions anywhere except the surface layer, such batches practically do not bear fruit.

When bacterial damage occurs, an unpleasant odor appears in the incubator and bag. It begins to ferment or rot. Even if it becomes overgrown, sick mushrooms will come out of it.

Condensation under the film can form even if the optimal microclimate is maintained and can be observed until the tenth to twelfth day from sowing, and may disappear on the 6th-7th day.

It looks like small round droplets of water - “saucers”. They appear as a result of the fact that the bag with the growing mycelium is warmer than the room air. This is a normal, physiological phenomenon - such condensate is transparent (slightly yellowish), the droplets are small, evenly distributed over the surface.

Click on three pictures below: in the left image there are transparent drops of moisture with a creamy tint; the blocks are overgrown with high quality, and the condensation has disappeared during the formation of primordia.

In the center you can see the brown liquid under the film, and on the right is the primordium, sick with bacteriosis from the same sac.

How to fix.
Observe microclimate parameters during incubation.

3. Infection of the incubator premises.

In this case, a plaque of green, less often gray and black color is located only in the perforations. Inside, under the film, the entire mass in the bag is well overgrown and white.

How to get rid of green trichoderma on the perforation of a block

In the case of isolated lesions, you can remove part of the straw (husk) from the cut by hand, treat the cut with 5% hydrogen peroxide or bleach and seal it with tape.

If almost all the holes are green, this indicates a high contamination of the room with mold spores. They are not visible to the naked eye. But if you inoculate the air on a Petri dish, on the third or fourth day it becomes overgrown with multi-colored colonies - see the photo at the beginning of the article on the right.

It is necessary to empty the incubator and chemically treat it with sporicidal disinfectants or fungicides.

Hair on an oyster mushroom block

On many old farms and poultry houses, even if the buildings have been abandoned for many years, specific pathogenic microflora remain. Most often, spores of various mold fungi.
In particular, such long black threads appear in the slot. This is a special species of mucoraceae - Spinellus fusiger. Popularly called “horsehair”.
And if the hair is white and grows from the bottom of the cap, this is a dispute. Read about them in the article

What to do with this beast?

Nothing new - follow the technology, carry out sanitation, set up the ventilation correctly. Since high air speed contributes to the spread of this scourge.

Various formations on caps

At all times, mushroom growers have noticed various formations on the caps. The reaction to their appearance varied, from complete indifference to panic. Gradually, mushroom growers got used to the fact that their mushrooms could “put on an unexpected outfit,” and the distributors of their products were not particularly bothered by this problem... Until enterprises began to increase production volumes and work with serious clients (large wholesalers and retail chains).

The consistency of product quality and its recognition have come to the fore, because the first thing a buyer sees when choosing a packaged oyster mushroom is its cap.

Having looked closely at the various formations on the cap, mushroom growers noticed that some disappear without a trace, some remain until the fruiting body acquires a marketable appearance, and others are accompanied by significant morphological changes.

And here we are again faced with the problem of the lack of appropriate terminology. Therefore, we will explain where the “cobweb”, “semolina”, “partitions”, “feathers”, “rags”, etc. come from on the hats.

"Cobweb"

The most harmless formation Moreover, this is a good sign showing that the relative humidity of the air has been successfully selected. During the active development of drusen, when biomass accumulates quickly enough, and the surface of the tightly closed caps does not yet allow effective evaporation and breathing, “aerial” mycelium appears on them, sharply increasing the ratio of surface to biomass. The surface of the cap becomes velvety or covered with a fairly dense “web”. But, as soon as the surface of the drusen caps increases (under optimal climate conditions), these formations disappear, absorbed by the main tissue of the cap. Sometimes this effect persists on large caps, lining a depression in the center where it is difficult for air currents to enter.

"Semolina"

Outwardly, it resembles the development of powdery mildew on cucumber leaves, which is why it is often diagnosed by mushroom growers as a disease. In fact, this formation was created by the oyster mushroom itself. This is the same “cobweb”, but fused into a denser formation, and not absorbed by the main tissue of the grown cap, which develops in not entirely favorable conditions. So the fruiting body tries to compensate for climate deficiencies (most often weak air currents), and if these shortcomings are not eliminated, then the “semolina” will remain present throughout the entire period of development of the fruiting body.

The fruiting bodies are quite marketable, but it should be taken into account that summer residents, who struggle with powdery mildew from year to year, are also consumers of our products.

"Partitions"

These formations have the same function as the “web” and “semolina”, but the situation in which the fruiting body forms them is much more critical. The partitions bear the main burden of evaporation and respiration. Most of the cap tissue has already died and is making its last efforts to save the spores located on the plates. This is often confirmed by the development of septa exactly above the cap plates. The caps of such fruiting bodies are a dark brick-yellow hue, which indicates serious problems with evaporation, and, consequently, with respiration. Often accompanied by lengthening of the pedicle. And if we do not take urgent measures to create a climate (although these particular fruiting bodies can hardly be helped), then we will get the effect of “rags” (often rags can be called not only the formations on the caps, but also the fruiting bodies themselves). Not only the main tissue of the cap dies, but also all the formations that were unable to compensate for the lack of a normal climate.

"Feathers"

They owe their appearance to the presence of aerosols in the air or... to watering (we won’t even discuss this anachronism). The culprits are aerosol generators, high-pressure nozzles and other devices that spray cold (!) water, which, without evaporating (...how can cold water evaporate in a warm room..?), settles on the caps of the fruiting bodies. Often, under the “feathers” formed by aerial mycelium, there is droplet water. That's why they appear above the depression in the center of the cap.

Believe me, attempts to increase the relative humidity of the air with cold water aerosol are fraught with many more surprises associated with morphological changes in fruiting bodies.

DIAGNOSTICS:

• The velvety appearance of the cap and the “web” in the early stages of fruiting body development are normal.
• Aerial mycelium fused into small balls, “semolina” - you should pay attention to the optimal climate parameters.
• “Partitions” - the climate is not properly organized or there has been a serious malfunction in the operation of the climate control equipment.
• Active development of aerial mycelium on the surface of the cap means the presence of too much unevaporated water aerosol in the air.