SOME MUSHROOM DISEASES AND THEIR CARRIERS / 



bubbles. In houses where these diseases occur mushroom flies have 

 been examined which carried on their somewhat spiny bodies and 

 legs hundreds of spores of these fungi. In addition to these, there 

 are other flies much like them in appearance which feed in the 

 compost and ordinarily do not injure mushrooms. They are, how- 

 ever, able to distribute the spores of these diseases in the same man- 

 ner as the flies producing the injurious mushroom maggot. All 

 of these flies move actively about through mushroom houses, both 

 by walking and by flight, and are undoubtedly responsible for the 

 rapid increase in the distribution of the diseases in large houses. 

 Diseased mushrooms develop an odor likely to attract some of the 

 larger carrion flies from outside, and these larger flies are capable 

 of carrying much greater numbers of spores throughout the house. 

 On this account particular attention should be paid to the proper 

 screening of the houses. Springtails also are adapted by nature, 

 through their fine, scaly coats of bristles and by their activities on 

 the beds, to further the distribution of these diseases. 



It has been noted that some growers are extremely careless in the 

 disposal of diseased compost. Cases are known to the writers 

 wherein compost cleared from beds in which serious loss from 

 disease has occurred and full of fungous spores was merely piled 

 outside the door of the house during the time the house was being 

 refilled. This permits the carriage of the disease into the house 

 and to the new compost both by the feet and clothing of the workers 

 and by the myriads of flies leaving this disease-infected material to 

 enter the house each time the door is opened. The house may be 

 thoroughly cleaned and disinfected, but under such circumstances 

 the crop is sure to be a loss through these diseases. 



CONTROL MEASURES 



In the event that either of the diseases described in this circular 

 makes its appearance in a restricted portion of the mushroom house, 

 its spread may be materially delayed by maintaining as great free- 

 dom as practicable from both flies and springtails. There is a pres- 

 ent tendency toward the use of varieties of mushroom spawn which 

 produce much better crops when maintained at temperatures in 

 excess of 60° F. The increased temperature maintained in com- 

 mercial establishments producing such mushrooms is likely to cause 

 more rapid multiplication and consequently greater abundance of 

 both mushroom flies and springtails and therefore to increase the 

 rapidity of disease distribution. Much can be done, however, to 

 offset these conditions by applying fumigation or other control 

 methods against these insects so frequently that the adults will be 

 killed practically as they emerge. It is the practice in large com- 

 mercial greenhouses to apply nicotine or cyanide fumigations for 

 certain insect pests even two to three times a week to attain this 

 result, and a good crop of mushroooms equals in commercial value 

 many of the greenhouse crops protected in this manner. 



NICOTINE 



The fact that nicotine is quite poisonous to flies of this type ren- 

 ders it possibly the most practicable fumigation material. It should 

 be used from medium to heavy strength and either dusted through 



