﻿26 
  

  

  THE 
  BED 
  SPIDER 
  ON 
  HOPS 
  IN 
  CALIFORNIA. 
  

  

  Table 
  VII. 
  — 
  Spraying 
  experiments 
  with 
  various 
  combinations 
  against 
  the 
  red 
  spider 
  on 
  

  

  hops. 
  

  

  No. 
  

  

  Date. 
  

  

  Material. 
  

  

  Application. 
  

  

  Num- 
  

   ber 
  of 
  

   mites 
  

  

  Num- 
  

   ber 
  of 
  

   mites 
  

  

  Per 
  

  

  cent 
  

  

  of 
  mites 
  

  

  Cost 
  per 
  

  

  100 
  

   gallons. 
  

  

  

  

  

  

  present. 
  

  

  killed. 
  

  

  killed. 
  

  

  1 
  

  

  July 
  15 
  

  

  Nicotine 
  sulphate, 
  40 
  per 
  cent, 
  1-750. 
  . 
  

  

  Thorough, 
  but 
  

  

  beaded. 
  

   do 
  

  

  450 
  

  

  263 
  

  

  58.4 
  

  

  $1.66 
  

  

  2 
  

  

  ...do 
  

  

  Nicotine 
  sulphate, 
  40 
  per 
  cent, 
  1-1,000. 
  

  

  414 
  

  

  376 
  

  

  90.8 
  

  

  1.25 
  

  

  3 
  

  

  ...do 
  

  

  Nicotine 
  sulphate, 
  40 
  per 
  cent, 
  1-2,000. 
  

  

  do 
  

  

  762 
  

  

  677 
  

  

  98.9 
  

  

  .62 
  

  

  4 
  

  

  ...do 
  

  

  Nicotine 
  sulphate, 
  40 
  per 
  cent, 
  1-3,000. 
  

  

  do 
  

  

  414 
  

  

  263 
  

  

  63.6 
  

  

  .416 
  

  

  5 
  

  

  July 
  16 
  

  

  Nicotine 
  sulphate, 
  40 
  per 
  cent, 
  1-60 
  

  

  do 
  

  

  237 
  

  

  185 
  

  

  78.1 
  

  

  1.08 
  

  

  6 
  

  

  ...do 
  

  

  Nicotine 
  sulphate, 
  40 
  per 
  cent, 
  1- 
  

   2,000; 
  lime-sulphur, 
  1-86. 
  

  

  do 
  

  

  312 
  

  

  273 
  

  

  87.5 
  

  

  .85 
  

  

  7 
  

  

  ...do 
  

  

  Nicotine 
  sulphate, 
  40 
  per 
  cent, 
  1- 
  

   3,000; 
  lime-sulphur, 
  1-86. 
  

  

  do 
  

  

  361 
  

  

  280 
  

  

  78.6 
  

  

  .64 
  

  

  8 
  

  

  ...do 
  

  

  Nicotine 
  sulphate, 
  40 
  per 
  cent, 
  1-750; 
  

   cresol 
  soap, 
  1-300. 
  

  

  Thorough, 
  not 
  

   beaded. 
  

  

  330 
  

  

  225 
  

  

  68.3 
  

  

  2.08 
  

  

  9 
  

  

  ...do 
  

  

  Nicotine 
  sulphate, 
  40 
  per 
  cent, 
  1- 
  

   1,000; 
  cresol 
  soap, 
  1-300. 
  

  

  do 
  

  

  164 
  

  

  111 
  

  

  67.7 
  

  

  1.67 
  

  

  

  

  

  10 
  

  

  July 
  17 
  

  

  Nicotine 
  sulphate, 
  40 
  per 
  cent, 
  1- 
  

   2,000; 
  cresol 
  soap, 
  1-300. 
  

  

  do 
  

  

  269 
  

  

  174 
  

  

  64.7 
  

  

  1.04 
  

  

  11 
  

  

  ...do 
  

  

  Nicotine 
  sulphate, 
  40 
  per 
  cent, 
  1- 
  

  

  3,000; 
  cresol 
  soap, 
  1-300. 
  

   Lime-sulphur 
  and 
  nicotine 
  sulphate, 
  

  

  do 
  

  

  201 
  

  

  115 
  

  

  57.2 
  

  

  .83 
  

  

  12 
  

  

  ...do 
  

  

  Thorough, 
  but 
  

  

  273 
  

  

  191 
  

  

  70 
  

  

  

  

  

  1-50. 
  

  

  beaded. 
  

  

  

  

  

  

  13 
  

  

  ...do 
  

  

  Lime-sulphur 
  and 
  40 
  per 
  cent 
  nicotine 
  

   sulphate, 
  1-50; 
  flour 
  paste, 
  4-100. 
  

  

  Thorough, 
  not 
  

   beaded. 
  

  

  163 
  

  

  157 
  

  

  96.3 
  

  

  

  14 
  

  

  ...do 
  

  

  Flour 
  paste, 
  4-100 
  

  

  do 
  

  

  657 
  

  

  444 
  

  

  67.5 
  

  

  .09 
  

  

  

  

  

  

  PURE 
  WATER. 
  

  

  Spraying 
  with 
  water 
  is 
  oru 
  of 
  the 
  most 
  successful 
  and 
  most 
  com- 
  

   monly 
  used 
  methods 
  of 
  controlling 
  the 
  red 
  spider 
  in 
  greenhouses. 
  

   With 
  a 
  strong 
  but 
  fine 
  stream 
  of 
  water 
  the 
  mites 
  are 
  washed 
  from 
  the 
  

   foliage 
  of 
  infested 
  plants 
  and 
  the 
  infestation 
  is 
  reduced 
  to 
  a 
  minimum. 
  

  

  It 
  was 
  thought 
  possible 
  to 
  wash 
  the 
  mites 
  from 
  the 
  hop 
  leaves 
  by 
  

   spraying 
  water 
  through 
  a 
  coarse 
  nozzle 
  at 
  200 
  pounds 
  pressure 
  with 
  

   about 
  as 
  successful 
  results. 
  This 
  experiment 
  was 
  accordingly 
  carried 
  

   out, 
  and 
  although 
  some 
  of 
  the 
  mites 
  were 
  washed 
  off, 
  many 
  were 
  left 
  

   and 
  were 
  later 
  seen 
  to 
  have 
  been 
  uninjured 
  by 
  the 
  force 
  of 
  the 
  spray. 
  

  

  The 
  lime-sulphur-and-flour 
  paste 
  and 
  the 
  flour 
  paste, 
  8-100, 
  are 
  so 
  

   cheap 
  that 
  even 
  though 
  between 
  50 
  and 
  70 
  per 
  cent 
  of 
  the 
  mites 
  could 
  

   be 
  killed 
  by 
  pure 
  water, 
  one 
  of 
  the 
  former 
  materials, 
  which 
  destroys 
  

   about 
  98 
  per 
  cent, 
  is 
  preferred. 
  

  

  VALUE 
  OF 
  A 
  SECOND 
  APPLICATION. 
  

  

  After 
  a 
  few 
  spraying 
  experiments 
  had 
  been 
  conducted 
  it 
  was 
  seen 
  

   that 
  the 
  sulphur, 
  the 
  lime-sulphur, 
  and 
  the 
  lye-sulphur 
  had 
  no 
  effect 
  

   upon 
  the 
  mites 
  except 
  by 
  actual 
  contact; 
  therefore 
  the 
  idea 
  of 
  placing 
  

   a 
  material 
  on 
  the 
  vines 
  which 
  would 
  kill 
  the 
  larvae 
  on 
  emergence 
  was 
  

   abandoned. 
  Although 
  nearly 
  100 
  per 
  cent 
  of 
  the 
  mites 
  living 
  upon 
  

   the 
  leaves 
  could 
  be 
  destroyed 
  by 
  the 
  spray, 
  the 
  eggs 
  were 
  uninjured 
  

   and 
  the 
  newly 
  hatched 
  larvae 
  feinfested 
  the 
  leaves 
  as 
  badly 
  as 
  before. 
  

   It 
  was 
  therefore 
  decided 
  to 
  spray 
  a 
  second 
  time 
  after 
  all 
  the 
  eggs 
  had 
  

   hatched 
  and 
  yet 
  early 
  enough 
  to 
  prevent 
  any 
  larvae 
  from 
  becoming 
  

   mature. 
  

  

  