﻿64 
  DECIDUOUS 
  FRUIT 
  INSECTS 
  AND 
  INSECTICIDES. 
  

  

  Commercial 
  tobacco 
  extracts 
  (blackleaf 
  tobacco 
  extract, 
  contain- 
  

   ing 
  2-^q 
  per 
  cent 
  nicotine 
  sulphate) 
  applied 
  at 
  a 
  dilution 
  of 
  1 
  to 
  

   150 
  gallons 
  of 
  water, 
  or 
  a 
  still 
  more 
  highly 
  concentrated 
  form 
  

   ( 
  'blackleaf 
  40/' 
  containing 
  40 
  per 
  cent 
  nicotine 
  sulphate) 
  applied 
  

   at 
  a 
  dilution 
  of 
  1 
  to 
  1 
  ,500 
  gallons 
  of 
  water, 
  may 
  be 
  used 
  with 
  arsenate 
  

   of 
  lead. 
  The 
  tobacco 
  extract 
  is 
  used 
  on 
  the 
  leaf 
  as 
  a 
  contact 
  remedy 
  

   against 
  the 
  nymphs 
  of 
  the 
  grape 
  leafhopper 
  and 
  the 
  arsenate 
  of 
  lead 
  

   on 
  the 
  fruit 
  against 
  the 
  larvae 
  of 
  the 
  grape 
  berry 
  moth. 
  Paris 
  green 
  

   and 
  arsenite 
  of 
  lime 
  should 
  not 
  be 
  mixed 
  with 
  the 
  tobacco 
  extracts 
  

   as 
  a 
  substitute 
  for 
  arsenate 
  of 
  lead, 
  for 
  serious 
  foliage 
  injury 
  results 
  

   from 
  these 
  combinations. 
  

  

  The 
  combination-spray 
  application 
  against 
  these 
  two 
  insects 
  

   should 
  be 
  made 
  by 
  the 
  "trailer" 
  method, 
  as 
  shown 
  in 
  Plate 
  VIII, 
  

   figure 
  2. 
  The 
  nymphs 
  of 
  the 
  grape 
  leafhopper 
  suck 
  the 
  juice 
  from 
  

   the 
  underside 
  of 
  the 
  grape 
  leaves 
  and 
  are 
  killed 
  by 
  the 
  tobacco 
  

   extracts 
  coming 
  in 
  contact 
  with 
  their 
  bodies; 
  hence, 
  in 
  making 
  this 
  

   application 
  to 
  the 
  underside 
  of 
  the 
  grape 
  foliage 
  most 
  of 
  the 
  grape 
  

   clusters 
  are 
  drenched 
  by 
  the 
  spray. 
  By 
  the 
  addition 
  of 
  arsenate 
  of 
  

   lead 
  this 
  application 
  may 
  also 
  act 
  as 
  a 
  treatment 
  against 
  the 
  larvae 
  

   of 
  the 
  grape-berry 
  moth. 
  

  

  Since 
  no 
  serious 
  infections 
  of 
  black 
  rot 
  have 
  occurred 
  in 
  the 
  vine- 
  

   yards 
  of 
  the 
  Lake 
  Erie 
  Valley 
  during 
  the 
  past 
  few 
  seasons, 
  the 
  stronger 
  

   fungicide 
  formula 
  does 
  not 
  appear 
  to 
  be 
  necessary. 
  Hence 
  the 
  

   combination 
  spray 
  formula 
  recommended 
  against 
  this 
  pest 
  is 
  as 
  

   follows 
  : 
  

  

  Lime 
  1 
  ("pounds. 
  . 
  3 
  

  

  Copper 
  sulphate 
  ^Bordeaux 
  formula 
  I 
  . 
  -do 
  3 
  

  

  Water 
  J 
  [gallons. 
  . 
  . 
  50 
  

  

  Arsenate 
  of 
  lead 
  (insecticide) 
  pounds. 
  . 
  3 
  

  

  Since 
  the 
  effectiveness 
  of 
  an 
  arsenical 
  spray 
  treatment 
  depends 
  

   upon 
  the 
  presence 
  of 
  the 
  poison 
  upon 
  the 
  blossom 
  clusters 
  and 
  upon 
  

   the 
  berries 
  when 
  the 
  larvae 
  hatch 
  from 
  the 
  eggs 
  and 
  commence 
  to 
  

   feed 
  upon 
  the 
  blossom 
  buds 
  and 
  berries, 
  and 
  since 
  this 
  period 
  varies 
  

   more 
  or 
  less 
  each 
  season, 
  it 
  is 
  impossible 
  to 
  give 
  definite 
  dates 
  at 
  

   which 
  the 
  applications 
  should 
  be 
  made. 
  Hence 
  the 
  development 
  of 
  

   the 
  blossom 
  clusters 
  and 
  the 
  formation 
  of 
  the 
  berries 
  will 
  doubtless 
  

   indicate 
  more 
  accurately 
  the 
  hatching 
  period 
  of 
  the 
  larvae. 
  The 
  

   following 
  spray 
  schedule 
  is 
  based 
  on 
  the 
  blossoming 
  period 
  of 
  the 
  

   grape 
  and 
  the 
  development 
  of 
  the 
  berries 
  : 
  

  

  First 
  application 
  just 
  previous 
  to 
  the 
  blossoming 
  period 
  (see 
  fig. 
  20) 
  

   to 
  poison 
  the 
  larvae 
  which 
  feed 
  in 
  the 
  blossom 
  cluster, 
  from 
  about 
  

   June 
  8 
  to 
  14. 
  

  

  The 
  second 
  application 
  should 
  be 
  made 
  immediately 
  after 
  blossom- 
  

   ing, 
  at 
  which 
  time 
  the 
  larvae 
  commence 
  to 
  feed 
  upon 
  the 
  newly 
  set 
  

   berries, 
  and 
  the 
  application 
  should 
  be 
  doubled 
  over 
  those 
  portions 
  

  

  