﻿6 
  DECIDUOUS 
  FRUIT 
  INSECTS 
  AND 
  INSECTICIDES. 
  

  

  6 
  acres 
  were 
  sprayed 
  with 
  tobacco 
  extract 
  No. 
  I. 
  An 
  acre 
  was 
  left 
  

   unsprayed 
  in 
  the 
  middle 
  of 
  this 
  block. 
  

  

  A 
  gasoline-engine 
  sprayer 
  outfit 
  was 
  used 
  to 
  make 
  the 
  application. 
  

   The 
  ''trailer" 
  method 
  of 
  application 
  was 
  employed. 
  

  

  About 
  15 
  per 
  cent 
  of 
  the 
  nymphs 
  of 
  the 
  first 
  brood 
  had 
  developed 
  

   wings 
  when 
  this 
  spray 
  application 
  was 
  made, 
  July 
  11 
  and 
  12. 
  Nearly 
  

   all 
  of 
  the 
  nymphs 
  were 
  about 
  full 
  grown 
  and 
  it 
  was 
  thought 
  desira- 
  

   ble 
  to 
  use 
  a 
  stronger 
  dilution 
  than 
  in 
  the 
  foregoing 
  experiment. 
  The 
  

   tobacco 
  extract 
  No. 
  I 
  was 
  used 
  at 
  a 
  dilution 
  of 
  1 
  gallon 
  to 
  100 
  gallons 
  

   of 
  water. 
  A 
  pressure 
  of 
  about 
  125 
  pounds 
  was 
  maintained 
  through- 
  

   out. 
  Two 
  leads 
  of 
  hose 
  were 
  used 
  and 
  about 
  275 
  gallons 
  of 
  liquid 
  

   were 
  applied 
  per 
  acre. 
  

  

  Within 
  about 
  three 
  weeks 
  after 
  the 
  application 
  was 
  made 
  the 
  dif- 
  

   ference 
  in 
  injury 
  on 
  the 
  sprayed 
  and 
  unsprayed 
  grape 
  leaves 
  became 
  

   noticeable. 
  Upon 
  the 
  unsprayed 
  vines 
  the 
  winged 
  adult 
  "hoppers" 
  

   were 
  very 
  numerous 
  and 
  the 
  leaves 
  were 
  commencing 
  to 
  turn 
  brown 
  

   and 
  only 
  a 
  small 
  amount 
  of 
  new 
  growth 
  was 
  being 
  made. 
  

  

  Upon 
  the 
  sprayed 
  vines, 
  on 
  the 
  other 
  hand, 
  the 
  number 
  of 
  winged 
  

   adults 
  was 
  noticeably 
  much 
  smaller, 
  the 
  foliage 
  was 
  dark 
  green 
  and 
  

   healthy, 
  and 
  the 
  new 
  growth 
  of 
  vine 
  was 
  quite 
  thrifty 
  throughout 
  

   the 
  growing 
  season. 
  When 
  the 
  fruit 
  commenced 
  to 
  ripen 
  it 
  became 
  

   quite 
  evident 
  that 
  the 
  berries 
  and 
  the 
  clusters 
  would 
  be 
  smaller 
  and 
  

   the 
  fruit 
  not 
  so 
  purple 
  in 
  color 
  upon 
  the 
  unsprayed 
  vines 
  as 
  upon 
  

   those 
  that 
  were 
  sprayed. 
  Plate 
  II, 
  figure 
  1, 
  shows 
  a 
  vine 
  in 
  the 
  

   unsprayed 
  plat. 
  Plate 
  II, 
  figure 
  2, 
  shows 
  a 
  vine 
  in 
  the 
  sprayed 
  plat. 
  

   When 
  the 
  crop 
  was 
  harvested 
  the 
  sprayed 
  plat 
  yielded 
  128 
  baskets 
  

   of 
  grapes 
  per 
  acre 
  more 
  than 
  the* 
  unsprayed 
  plat. 
  This 
  fruit 
  was 
  

   sold 
  at 
  10 
  cents 
  per 
  basket, 
  giving 
  a 
  gross 
  cash 
  gain 
  of 
  $12.80 
  per 
  acre. 
  

   The 
  cost 
  of 
  spray 
  material 
  and 
  labor 
  of 
  making 
  the 
  application 
  

   against 
  this 
  pest 
  was 
  as 
  follows: 
  

  

  Team 
  and 
  driver 
  per 
  day 
  $4. 
  50 
  

  

  Two 
  men 
  to 
  apply 
  spray, 
  $1.75 
  per 
  day 
  3. 
  50 
  

  

  Tobacco 
  extract 
  No. 
  I, 
  275 
  gallons 
  per 
  acre 
  2. 
  33 
  

  

  Six 
  acres 
  sprayed 
  per 
  day, 
  cost 
  per 
  acre 
  3. 
  66 
  

  

  Increased 
  cash 
  yield 
  per 
  acre, 
  sprayed 
  plat 
  12.80 
  

  

  Cost 
  of 
  material 
  and 
  application 
  per 
  acre 
  3. 
  66 
  

  

  Cash 
  increase 
  per 
  acre 
  on 
  sprayed 
  vines 
  9. 
  14 
  < 
  

  

  Thus 
  the 
  net 
  yield 
  on 
  the 
  sprayed 
  plat 
  after 
  deducting 
  all 
  expense 
  

   of 
  labor 
  and 
  material 
  was 
  $9.14 
  per 
  acre. 
  In 
  addition 
  to 
  this 
  increase 
  

   in 
  crop 
  yield 
  the 
  sprayed 
  vines 
  made 
  a 
  more 
  vigorous 
  and 
  healtlry 
  

   growth 
  than 
  did 
  the 
  unsprayed 
  vines, 
  and 
  the 
  fruit 
  was 
  of 
  much 
  

   better 
  quality. 
  

  

  