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Oyster mushrooms are quite resistant to diseases and pests. It is for their unpretentiousness that mushroom growers value them. However, even with them there are problems with artificial cultivation. It happens that the oyster mushroom turns yellow, and also dries out and cracks. Most often, the reasons are care errors, the appearance of a disease, or an attack by pests.
Why do oyster mushrooms turn yellow
This can happen to oyster mushrooms at any time, regardless of the growing stage. They may turn yellow for the following reasons:
- high humidity in the room;
- too dry air;
- inadequate ventilation;
- drafts;
- pests;
- disease;
- sudden changes in air humidity.
The color of the caps may become uneven. The appearance of yellow spots is due to such factors:
- poor substrate;
- fungal or bacterial disease;
- the impossibility of evaporation of drops of water falling on oyster mushrooms during watering or at high humidity.
Yellowing of fruiting bodies
What to do if oyster mushrooms turn yellow
First of all, you need to find out the reasons for this phenomenon. It is impossible to control the microclimate in the mycelium by eye, so you need to purchase a special device that will help maintain optimal humidity.
If the oyster mushrooms are covered with a yellowish coating, then most likely the humidity is too high.
If the hats not only turn yellow, but dry out and crack, and the legs darken, then this indicates too dry air.
If the humidity is normal, but there are yellowish spots on the oyster mushrooms, this means that there is no ventilation or it does not work well.
Cracks can appear during a draft, so it is important that the ventilation system does not create them. Air flows should not go at the level of growth of oyster mushrooms, their path should be directed higher and lower.
To exclude infections, you need to pluck the fruiting body and do an analysis to identify the pathogen. Microorganisms may be in the substrate, so it needs to be checked. If a pest is found, it is necessary to process it together with oyster mushrooms with special preparations.
Other diseases of oyster mushrooms and their elimination
There are other diseases of oyster mushrooms, due to which they can turn yellow. The mushroom picker should be well versed in them.
Bacteriosis
Oyster mushrooms can turn yellow with bacteriosis. They are not too often exposed to this disease. This usually happens during the warm season, when the air temperature is quite high and the humidity is high. A symptom of this disease is the appearance of spots on the surface of the fruiting body, the color of which varies from beige to rusty brown. Gradually, their surface becomes covered with mucus.
The cause of the disease is a bacterial infection caused by Pseudomonas tolaasii. The pathogen can enter the fruiting body from the soil. You need to pay attention to the following signs:
- yellow dots and spots are slippery when felt with hands;
- spots do not have clear edges;
- when pressed, the pulp is cottony and falls through;
- a very unpleasant odor emanates from the fruiting bodies.
Bacteriosis of oyster mushrooms makes them unusable
It is impossible to determine the exact presence of the disease and its causative agent by eye, it is necessary to conduct a laboratory analysis that will help identify it. If an infectious agent is not detected, then this is not a bacteriosis.
If red spots have well-defined borders, then this is not a bacterial infection. Dots and small spots (less than 1 mm) of a rusty, brownish-red color are damage caused by flying insects or larvae in the substrate.
If the spots are single and larger (from 2 to 3 mm), then these may be traces of drops of condensate or water that has fallen on the fruiting bodies during irrigation.
If the problem is in the soil, it is useless to treat oyster mushrooms. A fungus infected with a bacterial infection emits an unpleasant odor, overgrown with spots. Sick bunches need to be plucked and destroyed.
With frequent damage to oyster mushrooms by bacteriosis, it is recommended to add calcium chloride to the substrate.
vermin
If the fruiting bodies turn yellow, this can be caused by fungal mosquitoes, midges and other pests. The mushroom scientist usually does not notice the parasites themselves: he does not pay attention to solitary flying midges, and the larvae are inside the mushrooms.
Mushroom mosquitoes are especially dangerous, which significantly reduce the quality of mushrooms and yield. On oyster mushrooms, sciarids are most often planted. Their females lay their eggs in the substrate under the film next to the perforation. The larvae that emerge from them feed on the mycelium. The life cycle of mosquitoes is shortened at high temperatures and lengthened at lower temperatures. Mature individuals do not fly far from the blocks with the substrate and, after mating, again lay their eggs under the film.
Mushroom midge larvae
With a massive infection, they are able to completely destroy the rudiments of fungi. In addition, sciarids can be carriers of diseases and other pests.
If the fungus shriveled, began to turn yellow, you need to remove it from the substrate and examine the root under a magnifying glass. You can find the moves made by pests and the larvae of midges or mushroom mosquitoes themselves. Outwardly, they look like orange, white or pink worms.
Rusty dots scattered over the surface of the fruiting body may also indicate the presence of larvae.
It is necessary to fight mosquitoes and midges by treating the premises where mushrooms are grown with such means as Fastak, Arrivo, Decis Lux, belonging to the group of pyrethroids, as well as preparations based on organophosphorus compounds, for example, Nurel. To destroy the larvae, insecticides are added to the substrate while feeding the mycelium.
Prevention of diseases of oyster mushrooms
First of all, it is required to create optimal climatic conditions.
The grow room must be well insulated to prevent condensation from forming on the walls and other micro-organisms from growing on the ceiling.
It is necessary to carry out sanitary and hygienic measures, that is, to maintain cleanliness and control the development of diseases and the appearance of pests. The floor and walls in the room, as well as equipment and tools, should be washed and disinfected.
For prevention, treatment is carried out with such preparations as bleach solution, “Whiteness”, chloramine, hydrogen peroxide and others. It is recommended to strictly adhere to the instructions when using them and periodically change the means to avoid getting used to them by harmful microorganisms. It is desirable that the floor and walls are smooth: this way it is easier to wash them before proceeding with disinfection.
One of the most effective drugs with a wide spectrum of action, directed against bacteria, viruses, fungi
When working with chemicals, it is necessary to use personal protective equipment: an apron or gown, boots, gloves, goggles, a hat, a respirator.
Often, cover soil becomes a source of fungal infection, which must be treated with steam and formalin. Materials for its preparation must be properly stored – in uncontaminated places.
To prevent fungal midges, insecticides are used, which are sprayed on growing rooms.
So that larvae do not hatch from the eggs of harmful insects laid in the substrate, drugs that block the synthesis of chitin (Dimilin, Fetoverm) are added to it.
Conclusion
If the oyster mushroom turns yellow, it is necessary to find out the causes of the phenomenon. To prevent this from happening, it is important to initially create the right conditions for mushrooms and take preventive measures to treat the premises and the growing environment.