

CIRCULAR No. 251 



DECEMBER, 1932 



UNITED STATES DEPARTMENT OF AGRICULTURE 

 WASHINGTON, D. C. 



MUSHROOM GROWING IN THE UNITED STATES 



By Edmund B. Lambert, Associate Pathologist, Division of Mycology and 

 Disease Survey, Bureau of Plant Industry 1 



CONTENTS 



Page 



The cultivated mushroom 1 



Development of the industry 3 



Spawn 3 



Pure-culture bottle spawn 4 



Varieties 7 



Structures for raising mushrooms 8 



House construction 9 



Cultural practice 10 



Preparation of a suitable compost 11 



M anure substitutes and supplements 15 



Spawning and casing 18 



Cultural practice — Continued. Page 



Growing conditions 19 



Sanitation and disinfection 22 



Diseases 23 



Bubbles 23 



Bacterial spot 25 



Other diseases 25 



Insect pests 27 



Prevention and control 28 



Harvesting, packing, and marketing 28 



Costs and returns.. 30 



THE CULTIVATED MUSHROOM 



The common cultivated mushroom, Agaricws campestris L., is 

 the only species cultivated in the United States, and the majority of 

 the mushrooms consumed are of this one general type. In the 

 European and oriental markets several other kinds of fleshy fungi 

 are sold. The cepes and truffles of Europe, the kames of North 

 Africa, and the shii-take and matsu-take of the Orient are examples. 

 A few of these reach our country as dried or canned products, but 

 no systematic attempt to introduce their cultivation has been made. 



The mushroom is a member of a large group of plants known 

 as fungi. The natural life cycle of the cultivated mushroom begins 

 with the germination of the spore, which gives rise to a threadlike 

 growth called mycelium. This mycelium seeks, absorbs, and trans- 

 ports food, and usually grows extensively underground (fig. 1) before 

 appearing on the surface to produce the mushroom of commerce. 

 The mushroom completes the life cycle by producing and liberating 

 spores, which are found on the gills radiating from the stem on the 

 under side of the cap. (Fig. 2.) Thus there are three distinct phases 





1 This circular is based on surveys of commercial practice in Pennsylvania. New York, 

 Ohio, Illinois, and Minnesota in 1928, 1929, and 1930, and experiments on cultural prac- 

 tice, artificial manure, and disease control in the experimental mushroom house at the 

 Arlington Experiment Farm, Rosslyn, Va. The section on costs and returns is based on 

 the records of several successful growers in eastern Pennsylvania. The graphs of New 

 York prices are based on quotations in The Producers Price Current. The writer i> 

 especially grateful to several commercial growers and spawn makers in eastern Pennsyl- 

 vania for their friendly cooperation. 



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