Formaldehyde has been used as a fungicide, pesticide and disinfectant for many years. If formaldehyde can be made odorless and non-volatile, and still maintain its fungicidal and pesticidal properties, its usefulness would be greatly extended. 

According to the invention the odorless formaldehyde may be used in enclosed buildings. Further more, this odorless formaldehyde, unlike ordinary formaldehyde, is not toxic to plants, in particular, the mushroom mycelium as in mushroom growing, when used in proper concentrations. So it is not necessary to "sterilize" with ordinary formaldehyde .

The odorless formaldehyde is merely added to the soil or peat so that these materials are immediately ready for use. Another very important advantage is that in the former method of "sterilizing," the protective effect of the formaldehyde was used up, and was thus lost when the soil or peat was aerated. On the other hand, the formaldehyde of this odorless formaldehyde chemical compound is only slowly released (as later explained) so that protection continues during growth of plants or mushrooms.

FORMALDEHYDE SODIUM BISULFITE (FSB)

Process -

For mixing with peat, to be used to "case" spawned compost in mushroom beds, 4,4 grams of the solid powder, formaldehyde sodium bisulfite are mixed with 70 lbs. peat, which is sufficient peat to case 22 square feet of bed space. It has been found that quantities of from 1 to 10 grams per 70 pounds of casing material are effective. At present, Benlate and Zineb fungicides are mixed with the peat casing to prevent diseases, especially Mycogone and Verticillium, known to mushroom growers as "Bubbles."

FORMALDEHYDE SODIUM BISULFITE (FSB) Advantages -

• The advantage of using formaldehyde sodium bisulfite in place of these two fungicides is that resistance of these diseases to formaldehyde is unknown and is probably impossible due to the chemical configuration of formaldehyde.
• Resistance is building up now against Benlate and Zineb, so that mushroom growers are forced to search for new fungicides.
• In tests with formaldehyde sodium bisulfite under conditions of mixing with peat casing as described, the occurences of these diseases was reduced to 0.1%.
• Formaldehyde sodium bisulfite may also be sprayed on mushroom beds where mushrooms have been growing.
•  Concentrations of from 0.001 to 0.1% are suitable for use.