Dry bubble (Verticillium fungicola var. fungicola) infection belongs to the top three most serious diseases in the mushroom sector. Each year this fungal disease costs the industry millions of euros worldwide in loss of profits, extra labour costs and money spent on crop protection methods. A special poster developed by AdVisie can lend you a helping hand in identifying and controlling this problem.

The incidence of dry bubble in Europe this spring was not such a huge problem, but at the end of the summer it struck back with force. As a result harvesting many third flushes was impossible and in some cases even the second flushes were affected. An important weapon in the control of bubble is timely identification and taking the right steps to prevent the infection spreading to other growing rooms.

Many growers were asking for illustrated material to help recognize bubble. Adequate instructions illustrated by clear photographs of bubble are a must - particularly during the holiday period, when inexperienced seasonal workers are employed. To meet this demand, AdVisie has developed a poster clearly illustrating how to recognize bubble infection, outlining the steps that have to be taken once it has been identified and how to isolate and control the disease.

Excellent aid

Recognizing dry bubble in time with manual harvest but also when inspecting for diseases two to three days before harvesting is very important if the infection is prevalent. Regular employees usually know how to recognize bubble but new personnel, casual labour, students and seasonal workers lack this experience. To make it easier for them to recognize infected mushrooms, six photographs show bubble in various stages and forms. This makes identification on the beds easier.

According to Frans Brienen, grower and chairman of the CNC, teaching pickers to recognize bubble is very important. “There aren't many clear illustrations available so this poster is ideal”. The poster has been hung in a prominent place in the canteen.

Help! What now?

When bubble has been signalled and reported, the correct action must be taken. The green box on the poster lists the "do's" and the red box the "don'ts". These tips are handy for grower and picker alike. Growers should give clear instructions, which must be observed by pickers if bubble has been reported. 

If no action plan has been agreed or the guidelines are not strictly observed by all concerned, there is a serious risk of spreading the bubble infection over the bed, through the entire growing room or even to other rooms. It is very important not to touch bubble, as the spores rapidly spread the infection. Leaving bubble untreated is the wrong course of action - this simply increases the risk of the spores spreading. Spores will also be quickly spread by spraying or by insects in growing rooms. Flies and midges can carry hundreds of minute spores. 

Control

Control depends on which flush is affected, and the size and number of the bubble infection. If there are just a few, solitary bubbles in a first flush, isolating the infection with an upended, bottomless bottle or tin can is an excellent solution. This stops the spores spreading any further. The bubble can also be dealt with by covering it with a plastic bag, removing it from the bed then pouring a formalin solution over the spot. Removing bubble is not without risks. Even if it has been isolated, the journey through the buildings often increases the chances of spreading infection.

If large patches of bubble occur cover with absorbent paper and treat with a disinfectant.  If a whole section of a bed is infected the drastic, but most effective method is to apply steam. This painful choice is the best way to halt the spread of disease. If a grower decides to harvest the other mushrooms, seal off the infected area with plastic foil to prevent the spores spreading.

Ordering the poster

The ‘Verticillium and Mycogone, recognize and control' poster is laminated, A3 format. It is available in Dutch, German, English, Polish and Turkish. Each poster costs € 10,- excluding postage and administration charges. It can be ordered from AdVisie.

To order: fax your details to 0031/475537162 or apply via e-mail to info@champignonadvies.nl. State the number of posters required and the language(s).