﻿OCT. 
  4, 
  1922 
  STEINER 
  AND 
  HElNIvY 
  : 
  CONTROL 
  OF 
  INJURIOUS 
  NEMAS 
  369 
  

  

  There 
  have 
  been 
  seen 
  no 
  published 
  statements 
  made 
  concerning 
  the 
  

   culture 
  of 
  predatory 
  soil 
  nemas. 
  Menzel 
  seems 
  to 
  have 
  kept 
  Monon- 
  

   chus 
  papillatus 
  specimens 
  for 
  only 
  a 
  short 
  time 
  in 
  a 
  small 
  amount 
  of 
  

   water, 
  simply 
  in 
  order 
  to 
  perform 
  his 
  experiments 
  on 
  their 
  feeding 
  

   habits. 
  Therefore, 
  it 
  was 
  first 
  necessary 
  to 
  invent 
  simple 
  and 
  practical 
  

   methods 
  for 
  rearing 
  mononchs. 
  

  

  III. 
  METHODS 
  OF 
  CULTURE 
  OF 
  MONONCHUS 
  PAPILLATUS 
  BASTIAN 
  

  

  The 
  greatest 
  difficulty 
  in 
  rearing 
  minute 
  soil 
  organisms, 
  especially 
  

   soil 
  nemas, 
  is 
  to 
  devise 
  a 
  culture 
  medium 
  permitting 
  at 
  any 
  time 
  the 
  

   study 
  and 
  inspection 
  of 
  the 
  reared 
  animals 
  and 
  offering 
  as 
  far 
  as 
  possible 
  

   natural 
  conditions. 
  Soil, 
  however, 
  even 
  in 
  small 
  quantities, 
  is 
  not 
  

   transparent. 
  If 
  then, 
  the 
  organism 
  to 
  be 
  cultured 
  is 
  to 
  be 
  continuously 
  

   observed, 
  ordinary 
  soil 
  cannot 
  be 
  used 
  as 
  a 
  culture 
  medium.' 
  

  

  A. 
  Culture 
  in 
  a 
  drop 
  of 
  water 
  on 
  a 
  concave 
  slide. 
  — 
  The 
  first 
  attempt 
  

   to 
  rear 
  the 
  mononchs 
  was 
  in 
  a 
  small 
  drop 
  of 
  water 
  on 
  a 
  concave 
  slide. 
  

   Mononchus 
  papillatus 
  specimens 
  at 
  different 
  stages 
  of 
  growth 
  were 
  

   isolated 
  in 
  water-drop 
  cultures, 
  and 
  Heterodera 
  larvae, 
  different 
  species 
  

   of 
  Rhabditis 
  or 
  Anguillula 
  aceti, 
  added 
  as 
  food. 
  By 
  this 
  method 
  it 
  was 
  

   possible 
  to 
  keep 
  mononchs 
  alive 
  for 
  from 
  one 
  to 
  three 
  weeks, 
  if 
  the 
  

   water 
  was 
  changed 
  daily. 
  In 
  cultures 
  of 
  this 
  sort 
  the 
  mononchs 
  seemed 
  

   to 
  remain 
  in 
  very 
  good 
  condition 
  for 
  several 
  days; 
  they 
  were 
  easy 
  to 
  

   observe 
  and 
  study, 
  and 
  it 
  was 
  not 
  difficult 
  to 
  get 
  a 
  record 
  of 
  the 
  

   number 
  of 
  nemas 
  eaten 
  or 
  destroyed 
  by 
  them. 
  However, 
  after 
  a 
  short 
  

   time 
  had 
  elapsed, 
  all 
  animals 
  reared 
  in 
  pure 
  water 
  cultures 
  became 
  

   sluggish 
  and 
  finally 
  died. 
  

  

  B. 
  Culture 
  on 
  concave 
  slides 
  with 
  soil 
  and 
  water. 
  — 
  After 
  a 
  number 
  of 
  

   failures 
  with 
  the 
  foregoing 
  method, 
  we 
  tried 
  to 
  get 
  more 
  natural 
  

   conditions 
  by 
  adding 
  small 
  quantities 
  of 
  soil 
  to 
  the 
  drop 
  of 
  water 
  on 
  the 
  

   concave 
  slide. 
  It 
  was 
  seen 
  immediately 
  that 
  the 
  nemas 
  under 
  such 
  

   conditions 
  grew 
  better, 
  and 
  could 
  be 
  kept 
  alive 
  for 
  a 
  much 
  longer 
  time 
  . 
  

   After 
  some 
  experience, 
  we 
  were 
  able 
  to 
  rear 
  the 
  mononchs 
  by 
  this 
  

   method 
  from 
  the 
  first 
  larval 
  stage 
  up 
  to 
  the 
  adult 
  stage 
  and 
  even 
  to 
  the 
  

   point 
  of 
  producing 
  eggs. 
  The 
  following 
  points 
  should 
  be 
  kept 
  in 
  view. 
  

  

  1. 
  In 
  order 
  to 
  render 
  the 
  observations 
  comparatively 
  eas}^ 
  only 
  a 
  

   small 
  quantity 
  of 
  soil 
  should 
  be 
  used. 
  A 
  larger 
  amount 
  of 
  soil 
  furnishes 
  

   a 
  much 
  better 
  medium 
  for 
  the 
  nemas, 
  but 
  the 
  investigator 
  will 
  have 
  

   difficulty 
  in 
  finding 
  and 
  controlling 
  them. 
  By 
  trials, 
  any 
  investigator 
  

   can 
  find 
  the 
  best 
  amount 
  of 
  soil. 
  

  

  2. 
  The 
  nature 
  of 
  the 
  soil 
  is 
  not 
  of 
  great 
  importance. 
  Our 
  experi- 
  

  

  