Lately I am getting a lot of phone calls again about cobweb disease. The growers see the first signs appearing at the end of the first flush and by the time the second flush is starting, the problem practically gets out of control. To beat the problem it is necessary to know where the disease is coming from and how it grows and spreads.

The cobweb mould is a soil born fungus, using a vector (taxi). The vector may be sand, dust, casing soil and all different materials used by the people on the farm. Think of brooms, shovels but also mushroom harvesting equipment. This way the spores of the fungus are transported. But the fungus does not have to reach the state of sporulation to be infectious. If the fungus is damaged is splitters like glass. Small particles of the fungus can regrow fast into a new patch of cobweb again. So only touching the fungus by hand or by watering is enough to spread it like wildfire. It grows best under warm and moist conditions. So to slow it down it will help to lower the RH in the room and to drop the temperature a bit. But it will not stop it.To stop it you will have to find the origin of the infection and stop that. Many of the infections I see at this moment seem to start during the first flush so I immediately look at the harvesting on the farm.

We make sure pickers change the gloves regularly and disinfect the knives every day. The clothes of the pickers have to be changed daily and we look at the logistics of the farm. No one is allowed to move backwards in the schedule. In other words, if you where in a second flush, never go back into the first. For the grower it means a lot of cloth changing. After every check of the rooms. On many farms it is also necessary to look at the handling of the trays. Testing showed that many of the multiple use trays are infected with moulds. Even trays that are claimed to be disinfected. An effective method is to make sure that multiple trays are staying in the room where they are used. So if they are left over after the first flush, leave them in that room and use them in the second flush. If trays are coming out of the room with a possible infection, store them separately. And not in a room with other packaging.

The best way is to carry out the disinfection yourself. Steam the incoming trays properly in a container or a room designed for steaming out. Preferably not in a cookout room because the trays will smell terribly after that. After cooking out one can use a swab test and an agar tray to see if the trays are clean enough to be allowed onto the farm.

So to eliminate this disease make a list of possible infection moments and go through the list one by one. Only this way, by taking out all possible infection points, the disease can be controlled. Because chemical control is almost impossible and most of the times not allowed. And if you see the disease it is already to late to do something. The only thing left at that moment is to cover it widespreaded with salt and to stop watering immediately. And then start eliminating it with all possible measures.

We know most fungi to be beautiful to see and a number of them are also very tasty. But that they can also be deadly proves the discovery of a rare black fungus in patients in India. Black fungus infection (Mucormyosis) has struck in this country.

The infection is caused by various fungi. These so-called mucormycetes grow in the soil, in dirt and on rotting material, including rotting leaves or wood. People get the infection by inhaling the fungal spores that float around in the air and dust. These spores get trapped in the nasal passages and sinuses and that’s what causes the disease.

Not everyone exposed to the spores will get the infection. But the increase in the number of cases in India is probably due to the disease showing up in patients who have had corona and therefore have a less immune system. A connection is also seen with the drugs used to combat Covid-19. People with diabetes would also be extra sensitive to getting the infection.

The disease infects the nerves, brain and lungs. If the fungus spreads to the brain, the risk of death is 50%. Early diagnosis can be a life saver, but even then fighting the infection will be a tough task.

One of the most seen disease in mushroom farms is the dry bubble, caused by the fungus Verticillium fungicola. Its easy to get an infection in the farm and because the disease is very infectious it can spread quickly through the whole farm. Especially in big farms, where many pickers are working, the dry bubble will spread very fast and can cause a lot of damage and be that bad that 3rd breaks may be lost. Pickers should be getting all the information about the dry bubbles so they can detect the infection in an early stage.

2021 Blog week 7 Article dry bubble

A dry bubble in a 2nd break.

Dry bubble is generally caused by spores around the farms in windy, dusty conditions. On filling days when its windy outside with dust in the air its very well possible to get the dry bubbles into the farm. When they are spotted before he 1st break, the infection came in at filling. Once inside it’s a matter of time before the spores are everywhere if not handled well. Hygiene on the farm should be checked and especially have a good look at all the materials that are used for your mushroom waste like stem bins. Spores of bubbles will be present there if not cleaned well and can be spread if materials are getting moved between rooms. Also pickers are a concern for spreading the infection. Spores are sticky so everything that gets touched after touching a bubble can get infected, be aware!!!, it can go rapidly.


Removing the bubbles is off course also very important. When the pickers don’t recognize a bubble and are picking mushrooms while touching dry bubbles it will be always be hard to control the infection rate. Educate them well and spread around as much information as you have to inform pickers about the diastase and the big risk it has on the results of the farm. Let them, or the picking lead, report the infection so a special crew can handle it the right way.


When the pickers recognize the bubbles, the next step is removing the infection as soon as possible. Makes sure when you remove the bubble you don’t spread the spores what will results in more bubbles within 4 to 5 days. Use a wet tissue to cover infected spots too avoid the spread and remove all the spot including the casing soil, using a plastic bag. Close the bag immediately after you have the bubble and surrounded casing soil inside and remove the bag from the farm as soon as possible. You can also leave it in the affected room and remove it after cook-out. After removing it use salt or ammonia to cover the infected area and inspect the area every day to see if the infection is spreading.


It all comes down to a good hygiene, organization and education. Infection can occur suddenly but if threated the right way can also be stopped rapidly. Organize it well so that infections get removed before rooms get picked or watered, those are moments when spores will spread. If everybody recognizes the disease and knows what to do and handles right, bigger problems can be avoided. Hygiene is key, not only for dry bubbles, and should never be underestimated.

Erik de Groot
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We know the immune system is important for staying healthy, but what exactly is it and what can we do to support it?

The immune system is a complicated network of cells, tissues and organs in your body that protect against infection and disease. Given that there are so many pieces to the puzzle, there’s not one easy fix that can transform a weak immune system into a strong one in a snap of the fingers, but nutrition certainly plays an important role in its function.

Key Nutrients For Supporting Your Immune System
There are certain micronutrients in the foods we eat that play a key role in supporting the immune system1. An important step you can take for your immunity is to ensure you’re getting the recommended daily allowances2 of these nutrients. Find out how each of them serves your body and which foods you can find them in.

Mushroom Council has developed a "Feed your immune" system campaign, where they talke about nutrients in food and especially in mushrooms.
For the complete article, click here
Source: Mushroom Council

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