﻿MYCETOPHILID 
  FLIES 
  AS 
  PESTS 
  OF 
  THE 
  CUCUMBER 
  PLANT. 
  259 
  

  

  Accordingly, 
  three 
  infested 
  pot-plants 
  were 
  placed 
  in 
  a 
  pail, 
  and 
  water 
  was 
  added 
  so 
  

   that 
  the 
  surface 
  of 
  the 
  soil 
  was 
  just 
  covered. 
  A 
  number 
  of 
  adult 
  flies 
  floated 
  to 
  the 
  

   surface 
  and 
  were 
  unable 
  to 
  rise 
  from 
  the 
  water. 
  After 
  immersion 
  for 
  12 
  hours 
  the 
  

   plants 
  and 
  soil 
  were 
  examined, 
  and 
  no 
  living 
  larvae 
  could 
  be 
  found. 
  A 
  number 
  of 
  

   larvae 
  had 
  left 
  the 
  pots 
  and 
  were 
  dead 
  at 
  the 
  bottom 
  of 
  the 
  pail. 
  Fresh 
  plants 
  were 
  

   then 
  planted 
  in 
  the 
  soil 
  of 
  these 
  pots, 
  but 
  no 
  further 
  attack 
  resulted. 
  In 
  consequence 
  

   immersion 
  of 
  the 
  pots 
  was 
  at 
  once 
  carried 
  out 
  on 
  a 
  large 
  scale, 
  with 
  entirely 
  satisfactory 
  

   results. 
  

  

  The 
  larvae 
  of 
  Plastosciara 
  perniciosa 
  are 
  as 
  susceptible 
  to 
  moisture 
  conditions 
  as 
  

   those 
  of 
  Pnyxia 
  scabiei. 
  Cucumber 
  roots 
  containing 
  many 
  thousands 
  of 
  larvae 
  were 
  

   placed 
  in 
  large 
  pots 
  with 
  soil 
  from 
  the 
  cucumber 
  border 
  in 
  which 
  the 
  plants 
  had 
  been 
  

   growing. 
  Some 
  pots 
  were 
  watered 
  so 
  that 
  the 
  soil 
  was 
  of 
  the 
  consistency 
  of 
  a 
  pudding, 
  

   while 
  others 
  were 
  kept 
  well 
  on 
  the 
  dry 
  side. 
  After 
  three 
  days 
  the 
  soil 
  was 
  examined 
  ; 
  

   the 
  larvae 
  in 
  the 
  wet 
  pots 
  had 
  left 
  the 
  roots 
  and 
  about 
  98 
  per 
  cent, 
  of 
  them 
  had 
  

   perished, 
  while 
  in 
  the 
  dry 
  pots 
  no 
  dead 
  larvae 
  could 
  be 
  found. 
  At 
  the 
  same 
  time, 
  in 
  

   both 
  cases 
  where 
  the 
  attack 
  had 
  broken 
  out 
  favourable 
  reports 
  were 
  received 
  from 
  

   the 
  growers, 
  and 
  an 
  improved 
  condition 
  resulted 
  in 
  the 
  health 
  of 
  attacked 
  plants 
  

   after 
  heavy 
  watering 
  had 
  been 
  carried 
  out. 
  

  

  