﻿OCT. 
  4, 
  1922 
  STEINER 
  AND 
  HEINLY 
  : 
  CONTROIv 
  OF 
  INJURIOUS 
  NEMAS 
  

  

  371 
  

  

  especially 
  in 
  the 
  matter 
  of 
  keeping 
  records 
  of 
  the 
  rate 
  of 
  growth 
  and 
  the 
  

   number 
  of 
  animals 
  destroyed. 
  

  

  D. 
  The 
  tube-culture 
  method. 
  — 
  Desiring 
  to 
  control 
  the 
  results 
  of 
  our 
  

   slide 
  cultures, 
  we 
  started, 
  after 
  several 
  other 
  experiments, 
  with 
  cultures 
  

   in 
  a 
  larger 
  amount 
  of 
  soil 
  in 
  small 
  glass 
  tubes, 
  which 
  were 
  placed 
  in 
  

   holes 
  bored 
  in 
  a 
  small 
  block 
  of 
  wood, 
  as 
  shown 
  in 
  Fig. 
  1. 
  A 
  small 
  

  

  Fig. 
  

  

  1. 
  Wooden 
  block 
  and 
  glass-tubes 
  with 
  soil 
  contents 
  illustrat- 
  

   ing 
  the 
  tube-culture 
  method 
  of 
  rearing 
  mononchs. 
  

  

  amount 
  of 
  sterilized 
  soil 
  was 
  placed 
  in 
  each 
  of 
  these 
  tubes, 
  moisture 
  

   added, 
  as 
  well 
  as 
  the 
  mononch 
  to 
  be 
  reared, 
  and 
  a 
  daily 
  supply 
  of 
  

   Rhabditis, 
  Anguilhda 
  or 
  Heterodera 
  as 
  food. 
  The 
  tubes 
  were 
  kept 
  in 
  a 
  

   moist 
  chamber. 
  If 
  a 
  large 
  amount 
  of 
  soil 
  was 
  used 
  it 
  was 
  not 
  necessary 
  

   to 
  renovate 
  the 
  tubes 
  for 
  several 
  weeks, 
  but 
  if 
  a 
  smaller 
  amount 
  

   was 
  used, 
  a 
  weekly 
  change 
  was 
  required. 
  The 
  chief 
  aim 
  was 
  to 
  secure 
  

   conditions 
  for 
  the 
  mononchs 
  as 
  near 
  as 
  possible 
  to 
  those 
  found 
  in 
  the 
  

   soil 
  of 
  fields. 
  

  

  Under 
  these 
  conditions 
  it 
  was 
  possible 
  to 
  rear 
  Mononchus 
  papillatus 
  

   in 
  a 
  shorter 
  time 
  than 
  on 
  concave 
  slides. 
  A 
  larger 
  number 
  of 
  eggs 
  was 
  

   also 
  produced. 
  If 
  a 
  sufficient 
  amount 
  of 
  food 
  was 
  added, 
  numerous 
  

   mononchs 
  could 
  be 
  reared 
  together 
  in 
  the 
  same 
  tube, 
  without 
  their 
  

   attacking 
  each 
  other. 
  

  

  The 
  best 
  method 
  for 
  inspecting 
  a 
  tube 
  was 
  to 
  pour 
  the 
  contents 
  into 
  

   one 
  or 
  more 
  large 
  watchglasses 
  and 
  then 
  dilute 
  with 
  a 
  large 
  quantity 
  of 
  

   water. 
  If 
  this 
  was 
  not 
  done, 
  eggs 
  and 
  larval 
  forms 
  easily 
  escaped 
  

   notice. 
  

  

  E. 
  Remarks 
  on 
  flower-pot 
  and 
  field 
  experiments. 
  — 
  Finally 
  a 
  series 
  of 
  

   host-plant 
  experiments 
  were 
  also 
  performed. 
  Flower 
  pots 
  and 
  soil 
  were 
  

   sterilized 
  in 
  an 
  autoclave, 
  and 
  sterilized 
  seeds 
  of 
  oatS, 
  tomato 
  and 
  

   cucumber, 
  planted. 
  The 
  seeds 
  were 
  sterilized 
  according 
  to 
  the 
  pre- 
  

   soak 
  method, 
  a 
  one 
  -tenth 
  per 
  cent 
  solution 
  of 
  commercial 
  formalin 
  

   being 
  used. 
  After 
  the 
  first 
  roots 
  were 
  formed 
  and 
  the 
  growth 
  began, 
  

   the 
  plants 
  were 
  infected 
  with 
  a 
  certain 
  number 
  of 
  Heterodera 
  radicicola 
  

   and 
  also 
  Mononchus 
  papillatus 
  added 
  at 
  the 
  same 
  time. 
  Unfortunately 
  

  

  