﻿24 
  

  

  THE 
  EED 
  SPIDER 
  ON 
  HOPS 
  IN 
  CALIFORNIA. 
  

  

  the 
  condition 
  and 
  extent 
  of 
  the 
  foliage 
  on 
  the 
  vines. 
  During 
  the 
  early 
  

   part 
  of 
  the 
  work 
  the 
  foliage 
  was 
  light 
  and 
  could 
  be 
  easily 
  sprayed, 
  

   while 
  later 
  on 
  it 
  became 
  dense, 
  and 
  thorough 
  work 
  was 
  quite 
  difficult. 
  

   The 
  results, 
  however, 
  prove 
  the 
  efficiency 
  of 
  the 
  lime-sulphur-and- 
  

   flour-paste 
  spray 
  in 
  killing 
  the 
  red 
  spider 
  on 
  the 
  hopvine. 
  

  

  FLOUR 
  PASTE. 
  

  

  The 
  efficiency 
  of 
  flour 
  paste 
  as 
  an 
  arachnicide 
  was 
  indicated 
  in 
  the 
  

   experiment 
  which 
  is 
  recorded 
  under 
  No. 
  14 
  of 
  Table 
  VII, 
  but 
  it 
  was 
  

   not 
  until 
  the 
  summer 
  of 
  1912 
  that 
  its 
  value 
  was 
  fully 
  realized. 
  During 
  

   spraying 
  experiments 
  with 
  nicotine 
  sulphate 
  and 
  flour 
  paste 
  upon 
  

   the 
  hop 
  aphis 
  it 
  was 
  observed 
  that 
  many 
  of 
  the 
  smaller 
  aphides 
  had 
  

   become 
  pasted 
  to 
  the 
  leaves. 
  From 
  this 
  data 
  it 
  was 
  assumed 
  that 
  a 
  

   solution 
  containing 
  a 
  larger 
  proportion 
  of 
  flour 
  paste 
  should 
  be 
  

   effective 
  against 
  the 
  more 
  delicate 
  aphides 
  and 
  mites, 
  and 
  the 
  follow- 
  

   ing 
  experiments 
  were 
  accordingly 
  conducted 
  upon 
  the 
  red 
  spider 
  on 
  

   hops: 
  

  

  Table 
  V. 
  — 
  Experiments 
  with 
  flour 
  paste 
  against 
  the 
  red 
  spider 
  on 
  hops. 
  

  

  Date. 
  

  

  Formula. 
  

  

  Number 
  

   of 
  mites 
  

   present. 
  

  

  Per 
  cent 
  

   of 
  mites 
  

   killed. 
  

  

  Cost 
  per 
  

   100 
  gal- 
  

   lons. 
  

  

  

  Flour 
  paste. 
  8-100. 
  

  

  435 
  

   781 
  

   452 
  

   882 
  

   477 
  

   908 
  

  

  100.0 
  

   99.8 
  

   99.8 
  

   100.0 
  

   100.0 
  

   99.8 
  

  

  $0. 
  176 
  

  

  June 
  27... 
  

  

  . 
  .do 
  

  

  .176 
  

  

  July 
  12.. 
  

  

  . 
  .do... 
  

  

  .176 
  

  

  Aug. 
  6. 
  . 
  . 
  

  

  ... 
  .do... 
  

  

  .176 
  

  

  Do... 
  

  

  ...do 
  

  

  .176 
  

  

  Aug. 
  9 
  

  

  . 
  .do... 
  

  

  .176 
  

  

  

  Total 
  : 
  

  

  

  

  3,759 
  

  

  199.9 
  

  

  

  

  Flour 
  paste, 
  10-100 
  

  

  

  July 
  16 
  

  

  805 
  

   908 
  

  

  99.9 
  

   99.9 
  

  

  .22 
  

  

  Aug. 
  

  

  do 
  

  

  .22 
  

  

  

  Total 
  

  

  

  

  1,712 
  

  

  199.9 
  

  

  

  

  

  

  1 
  Average. 
  

  

  These 
  experiments 
  prove 
  that 
  the 
  flour 
  paste, 
  8-100 
  and 
  10-100, 
  

   is 
  effective 
  against 
  Tetranychus 
  bimaculatus. 
  The 
  spray 
  pastes 
  the 
  

   mites 
  onto 
  the 
  leaves, 
  but 
  has 
  no 
  effect 
  upon 
  the 
  eggs, 
  and 
  in 
  control- 
  

   ling 
  the 
  mites 
  a 
  second 
  application 
  is 
  necessary. 
  

  

  The 
  neutrality 
  of 
  this 
  spray 
  was 
  proved 
  by 
  the 
  fact 
  that 
  when 
  

   applied 
  upon 
  the 
  foliage 
  and 
  blossoms 
  of 
  the 
  hop, 
  in 
  proportions 
  as 
  

   high 
  as 
  12 
  gallons 
  of 
  paste 
  to 
  100 
  gallons 
  of 
  spray, 
  no 
  injurious 
  effects 
  

   resulted. 
  When 
  sprayed 
  onto 
  the 
  burrs 
  and 
  delicate 
  hop 
  cones, 
  it 
  

   did 
  not 
  prevent 
  pollination 
  or 
  injure 
  the 
  appearance 
  of 
  the 
  scales. 
  

  

  When 
  mixed 
  in 
  the 
  spray 
  tank, 
  flour 
  paste 
  has 
  a 
  tendency 
  to 
  settle, 
  

   and 
  in 
  order 
  to 
  do 
  satisfactory 
  work 
  agitati< 
  n 
  is 
  necessary. 
  It 
  is, 
  

  

  