﻿SPRAYING 
  AGAINST 
  GRAPE 
  LEAFHOPPER. 
  3 
  

  

  number 
  of 
  the 
  insects 
  so 
  that 
  those 
  remaining 
  did 
  not 
  materially 
  

   affect 
  the 
  growth 
  of 
  the 
  vine 
  or 
  the 
  proper 
  ripening 
  of 
  the 
  fruit. 
  

  

  These 
  experiments 
  were 
  conducted 
  in 
  different 
  parts 
  of 
  the 
  town- 
  

   ship 
  and 
  several 
  types 
  of 
  sprayers 
  were 
  used 
  in 
  making 
  the 
  applica- 
  

   tions. 
  In 
  all 
  cases 
  the 
  "trailer" 
  method 
  was 
  employed; 
  that 
  is, 
  a 
  

   trailing 
  hose 
  about 
  20 
  feet 
  long 
  was 
  connected 
  to 
  the 
  discharge 
  of 
  the 
  

   spray 
  pump 
  and 
  a 
  short 
  rod, 
  about 
  2\ 
  feet 
  long, 
  carrying 
  a 
  large 
  nozzle 
  

   of 
  the 
  cyclone 
  type 
  set 
  at 
  right 
  angles 
  to 
  the 
  rod 
  was 
  attached 
  to 
  the 
  

   free 
  end 
  of 
  this 
  lead 
  of 
  hose. 
  This 
  rod 
  is 
  held 
  by 
  the 
  operator, 
  who 
  

   thrusts 
  the 
  nozzle 
  among 
  the 
  foliage 
  with 
  rapid 
  movements, 
  directing 
  

   the 
  nozzle 
  upward, 
  so 
  that 
  the 
  liquid 
  is 
  thrown 
  upon 
  the 
  underside 
  of 
  

   the 
  leaves. 
  (See 
  PI. 
  I, 
  fig. 
  1.) 
  

  

  Two 
  forms 
  of 
  commercial 
  tobacco 
  extract 
  were 
  used 
  in 
  these 
  experi- 
  

   ments: 
  No. 
  I 
  (blackleaf 
  extract) 
  contained 
  2.70 
  per 
  cent 
  nicotine; 
  

   No. 
  II 
  (blackleaf 
  40) 
  contained 
  40 
  per 
  cent 
  nicotine 
  sulphate. 
  In 
  

   all 
  of 
  the 
  experiments 
  which 
  follow 
  the 
  tobacco 
  extracts 
  are 
  refer- 
  

   red 
  to 
  by 
  number. 
  Tobacco 
  extract 
  No. 
  I 
  refers 
  to 
  the 
  form 
  con- 
  

   taining 
  the 
  lower 
  percentage 
  of 
  nicotine, 
  tobacco 
  extract 
  No. 
  II 
  to 
  

   the 
  form 
  containing 
  the 
  higher 
  percentage 
  of 
  nicotine. 
  At 
  the 
  dilu- 
  

   tions 
  used 
  no 
  decided 
  advantage 
  was 
  evidenced 
  in 
  favor 
  of 
  either 
  

   form 
  of 
  tobacco 
  extract. 
  Both 
  of 
  these 
  substances 
  killed 
  the 
  nymphs 
  

   that 
  were 
  hit 
  by 
  the 
  spray. 
  The 
  tobacco 
  extract 
  No. 
  I 
  at 
  a 
  dilu- 
  

   tion 
  of 
  1 
  part 
  of 
  extract 
  to 
  150 
  parts 
  of 
  water 
  killed 
  all 
  nymphs 
  

   that 
  were 
  made 
  thoroughly 
  wet 
  by 
  the 
  spray, 
  especially 
  the 
  smaller 
  

   nymphs, 
  between 
  the 
  first 
  and 
  fourth 
  molts. 
  The 
  full-grown 
  nymphs, 
  

   unless 
  thoroughly 
  soaked 
  by 
  the 
  spray 
  at 
  this 
  dilution, 
  would 
  some- 
  

   times 
  escape, 
  probably 
  because 
  their 
  longer 
  legs 
  held 
  their 
  bodies 
  

   some 
  distance 
  from 
  the 
  wet 
  surface 
  of 
  the 
  leaf. 
  The 
  tobacco 
  ex- 
  

   tract 
  No. 
  II 
  was 
  effective 
  at 
  a 
  dilution 
  of 
  1 
  part 
  of 
  extract 
  to 
  

   1,500 
  parts 
  of 
  water. 
  In 
  the 
  use 
  of 
  the 
  tobacco 
  extract 
  No. 
  II 
  — 
  

   as 
  with 
  the 
  tobacco 
  extract 
  No. 
  I, 
  where 
  a 
  large 
  percentage 
  of 
  

   the 
  nymphs 
  were 
  in 
  the 
  last 
  stage; 
  that 
  is, 
  just 
  about 
  to 
  develop 
  

   wings 
  (see 
  fig. 
  3) 
  — 
  a 
  dilution 
  of 
  1 
  to 
  1,200 
  or 
  1,300 
  may 
  be 
  more 
  

   effective 
  in 
  killing 
  the 
  nymphs. 
  In 
  the 
  several 
  experiments 
  con- 
  

   ducted, 
  however, 
  the 
  dilutions 
  varied 
  from 
  1 
  to 
  100 
  parts 
  of 
  water 
  

   to 
  1 
  to 
  150 
  with 
  tobacco 
  extract 
  No. 
  I, 
  and 
  from 
  1 
  to 
  1,000 
  to 
  1 
  to 
  

   1,500 
  with 
  tobacco 
  extract 
  No. 
  II. 
  In 
  all 
  of 
  these 
  variations 
  of 
  dilu- 
  

   tion 
  apparently 
  equally 
  good 
  results 
  were 
  obtained. 
  

  

  VINEYARD 
  EXPERIMENTS 
  IN 
  1911. 
  

  

  EXPERIMENT 
  IN 
  VINEYARD 
  OF 
  MR. 
  II. 
  II. 
  HARPER, 
  NORTH 
  EAST, 
  PA. 
  

  

  The 
  cast 
  side 
  of 
  the 
  vineyard 
  of 
  Mr. 
  IT. 
  H. 
  Harper, 
  North 
  East, 
  Pa., 
  

   adjoining 
  the 
  highway 
  had 
  been 
  badly 
  infested 
  by 
  the 
  grape 
  leafhopper 
  

  

  for 
  several 
  years. 
  Previous 
  to 
  the 
  undertaking 
  of 
  this 
  experiment 
  

  

  