﻿EXPERIMENTS 
  FOR 
  CONTROL. 
  

  

  27 
  

  

  During 
  July 
  the 
  mites 
  passed 
  from 
  larva 
  to 
  adult 
  in 
  8 
  days 
  and 
  

   during 
  April 
  the 
  incubation 
  period 
  was 
  7 
  to 
  10 
  days. 
  1 
  Basing 
  the 
  

   time 
  of 
  a 
  second 
  application 
  on 
  this 
  data, 
  7 
  days 
  was 
  decided 
  upon 
  

   as 
  the 
  interim 
  between 
  the 
  first 
  and 
  second 
  sprayings, 
  and 
  by 
  follow- 
  

   ing 
  out 
  this 
  plan 
  some 
  very 
  encouraging 
  results 
  were 
  obtained, 
  as 
  

   shown 
  in 
  Table 
  VIII. 
  

  

  Table 
  VIII. 
  — 
  Experiments 
  showing 
  value 
  of 
  a 
  second 
  application 
  in 
  spraying 
  for 
  the 
  red 
  

  

  spider 
  on 
  hops. 
  

  

  No. 
  

  

  Date. 
  

  

  Material. 
  

  

  Applica- 
  

   tion. 
  

  

  Num- 
  

   ber 
  of 
  

   mites 
  

   pres- 
  

   ent. 
  

  

  Num- 
  

   ber 
  of 
  

  

  mites 
  

   killed. 
  

  

  Per 
  

   cent 
  of 
  

   mites 
  

   killed. 
  

  

  Second 
  

   appli- 
  

   cation, 
  

   per 
  cent 
  

   killed. 
  

  

  1 
  

   2 
  

   3 
  

  

  July 
  6 
  

   July 
  19 
  

   ...do 
  

  

  Lime-sulphur, 
  36° 
  Baume, 
  1-86; 
  flour 
  paste, 
  

  

  4-100. 
  

   Lime-sulphur, 
  33° 
  Baume, 
  1-70; 
  flour 
  paste, 
  

  

  4-400. 
  

   Lime-sulphur, 
  33° 
  Baume, 
  1-70; 
  flour 
  paste, 
  

  

  4-100. 
  

  

  Thorough 
  . 
  

  

  do 
  

  

  do 
  

  

  593 
  

   143 
  

   509 
  

  

  543 
  

   142 
  

   440 
  

  

  90 
  

  

  99.7 
  

  

  86.4 
  

  

  97.1 
  

   99.7 
  

   92.9 
  

  

  It 
  will 
  be 
  noted 
  that 
  only 
  from 
  0.3 
  to 
  7.1 
  per 
  cent 
  of 
  the 
  original 
  

   number 
  of 
  mites 
  present 
  on 
  the 
  vines 
  were 
  present 
  after 
  the 
  second 
  

   application. 
  The 
  mites 
  which 
  hatched 
  from 
  the 
  few 
  eggs 
  that 
  

   remained 
  were 
  not 
  sufficiant 
  to 
  form 
  the 
  basis 
  for 
  a 
  reinfestation 
  and 
  

   the 
  work 
  was 
  accordingly 
  considered 
  satisfactory. 
  

  

  Unfortunately 
  some 
  of 
  the 
  plats 
  treated 
  were 
  covered 
  with 
  infested 
  

   morning-glory 
  vines, 
  which 
  were 
  severely 
  injured 
  by 
  the 
  mites, 
  and 
  

   which 
  later 
  resulted 
  in 
  a 
  migration 
  that 
  soon 
  reinfested 
  the 
  hop- 
  

   vines. 
  Morning-glory 
  was 
  not 
  present 
  in 
  one 
  plat, 
  however, 
  and 
  

   although 
  the 
  applications 
  were 
  made 
  so 
  late 
  that 
  the 
  vines 
  were 
  

   severely 
  injured, 
  the 
  results 
  to 
  be 
  expected 
  from 
  such 
  a 
  plan 
  were 
  

   clearly 
  proved. 
  These 
  vines 
  were 
  comparatively 
  free 
  from 
  mites 
  at 
  

   the 
  end 
  of 
  the 
  season 
  and 
  had 
  a 
  much 
  more 
  healthy 
  color 
  than 
  the 
  

   vines 
  in 
  the 
  adjoining 
  plats 
  which 
  were 
  used 
  as 
  checks. 
  

  

  FORMULAS 
  FOR 
  SPRAYS. 
  

  

  To 
  prepare 
  the 
  flour 
  paste, 
  mix 
  a 
  cheap 
  grade 
  of 
  wheat 
  flour 
  with 
  

   cold 
  water, 
  making 
  a 
  thin 
  batter 
  without 
  lumps; 
  or 
  wash 
  the 
  flour 
  

   through 
  a 
  wire 
  screen 
  with 
  a 
  stream 
  of 
  cold 
  water. 
  Dilute 
  until 
  there 
  

   is 
  1 
  pound 
  of 
  flour 
  in 
  each 
  gallon 
  of 
  mixture. 
  Cook 
  until 
  a 
  paste 
  is 
  

   formed, 
  stirring 
  constantly 
  to 
  prevent 
  caking 
  or 
  burning. 
  Add 
  suffi- 
  

   cient 
  water 
  to 
  make 
  up 
  for 
  evaporation. 
  (See 
  PI. 
  VI, 
  fig. 
  1 
  .) 
  

  

  For 
  spraying 
  with 
  flour 
  paste 
  alone, 
  use 
  8 
  gallons 
  of 
  paste 
  as 
  pre- 
  

   pared 
  above 
  to 
  each 
  100 
  gallons 
  of 
  water. 
  

  

  For 
  the 
  flour-paste 
  and 
  lime-sulphur 
  spray, 
  use 
  4 
  gallons 
  of 
  paste 
  

   to 
  each 
  100 
  gallons 
  of 
  spray 
  containing 
  the 
  lime-sulphur. 
  

  

  1 
  In 
  moderate 
  weather 
  allow 
  10 
  and 
  in 
  hot 
  weather 
  7 
  days 
  between 
  applications, 
  

  

  