﻿EXPERIMENTS 
  FOR 
  CONTROL. 
  

  

  31 
  

  

  leaves 
  were 
  readily 
  sprayed. 
  It 
  is 
  always 
  difficult 
  to 
  spray 
  thor- 
  

   oughly, 
  and 
  any 
  cultural 
  method 
  which 
  will 
  facilitate 
  effective 
  work 
  

   is 
  worth 
  while. 
  During 
  the 
  early 
  part 
  of 
  the 
  seasons 
  of 
  1911 
  and 
  1912 
  

   the 
  mites 
  were 
  observed 
  upon 
  the 
  lower 
  leaves 
  only 
  and 
  from 
  there 
  

   migrated 
  upward. 
  It 
  is 
  estimated 
  that 
  the 
  stripped 
  area 
  contains 
  

   about 
  40 
  or 
  50 
  leaves; 
  taking 
  the 
  average 
  number 
  of 
  mites 
  as 
  42 
  

  

  Fig. 
  7.— 
  Hopvine 
  tied 
  high 
  and 
  not 
  stripped; 
  lower 
  leaves 
  difficult 
  to 
  spray. 
  (Original.) 
  

  

  per 
  leaf 
  for 
  an 
  average 
  infestation, 
  the 
  theoretical 
  number 
  of 
  mites 
  

   that 
  would 
  be 
  removed 
  would 
  be 
  about 
  1,680 
  or 
  2,100 
  per 
  vine. 
  

  

  One 
  hopyard 
  which 
  was 
  stripped 
  before 
  the 
  mites 
  were 
  above 
  the 
  

   point 
  to 
  which 
  the 
  vines 
  were 
  to 
  be 
  stripped 
  was 
  observed 
  August 
  !>. 
  

   It 
  was 
  found 
  that 
  the 
  infestation 
  had 
  been 
  materially 
  checked. 
  

  

  It 
  is 
  believed 
  that 
  timely 
  stripping 
  of 
  the 
  vines 
  and 
  removal 
  ami 
  

   burning 
  of 
  the 
  infested 
  leaves 
  will 
  severely 
  check 
  the 
  infestation 
  and 
  

   in 
  some 
  eases 
  where 
  the 
  yards 
  are 
  not 
  filled 
  with 
  food 
  plants 
  will 
  

  

  