MUSHROOM PESTS AND THEIR CONTROL 



13 



rooms are IS. copropMIa Lintner, S. multiset a Felt, and S. agraria 

 Felt. They are much alike in appearance, habits, and life history, 

 and for practical purposes may be regarded as one species. Figure 

 3, 0, shows a drawing of an adult fly. Sciarid flies are slender, with 

 rather long legs and antennae. They usually carry their wings 



folded flat upon the 

 back when walking 

 or at rest. In color 

 they are black or 

 yellow black. The 

 males have a pair of 

 claspers at the apex 

 of the abdomen. 



The eggs (fig. 4) 

 of these flies are very 

 small, oval, white or 

 yellowish. They are 

 laid in the compost 

 or spawn, in cracks 

 in the casing soil, 

 or upon the mush- 

 rooms. Under favor- 

 able conditions of 

 temperature and 

 humidity the egg 

 hatches in 4 or 5 

 days into a legless 

 white larva, or mag- 

 got, with a shiny 

 blackhead ( fig. 3, A ) . 

 After feeding for 

 from 10 to 14 days 

 the larva approaches 

 the surface and 

 spins a fragile silken 

 cocoon, in which it 

 transforms into a 

 pupa (fig. 3, B). In 

 5 or 6 days the 

 adult fly emerges, 

 and it is capable of 

 mating within a few 

 hours. Females may 

 commence oviposi- 

 tion within 24 hours. 

 As each female is capable of laying from 200 to 300 eggs, and there is 

 very little natural mortality among the larvae, it will be realized that 

 the potential rate of increase is very great. 



No effective method of combating the maggots of these flies within 

 the beds is known. Control must be had through reducing the num- 

 ber of adult flies, thus decreasing the number of eggs laid. Traps 

 and insecticides are the principal means of killing the adult flies. 



Figure 3. — Stages of a mushroom fly, Sciara pauciseta: A, 

 larva, x 10 ; B, pupa, ventral view, X 15 ; C, adult, 

 X 12. 



