﻿551 
  

  

  their 
  efEect 
  is 
  not 
  always 
  tangible, 
  but 
  experiments 
  will 
  determine 
  

   their 
  value. 
  In 
  the 
  author's 
  hands, 
  lead 
  arsenate 
  gave 
  constantly 
  

   favourable 
  results 
  over 
  a 
  period 
  of 
  seven 
  years, 
  and 
  its 
  efficacy 
  increased 
  

   as 
  more 
  knowledge 
  regarding 
  date 
  and 
  mode 
  of 
  appUcation 
  was 
  

   acquired 
  and 
  appHed. 
  In 
  1913, 
  the 
  percentage 
  of 
  mortahty 
  attained 
  

   was 
  94" 
  2. 
  Regional 
  differences 
  alone 
  cannot 
  account 
  for 
  those 
  reported 
  

   cases 
  where 
  the 
  percentage 
  was 
  zero. 
  Nor 
  can 
  it 
  be 
  said 
  that 
  in 
  the 
  

   experiments 
  here 
  referred 
  to 
  only 
  sparsely 
  infested 
  plots 
  were 
  treated, 
  

   for 
  the 
  trials 
  were 
  made 
  during 
  seven 
  years. 
  While 
  the 
  lack 
  of 
  

   abundant 
  skilled 
  labour 
  prevents 
  full 
  use 
  being 
  made 
  of 
  arsenate 
  of 
  

   lead 
  on 
  large 
  estates, 
  this 
  objection 
  but 
  rarely 
  apphes 
  to 
  small 
  vine- 
  

   yards. 
  In 
  the 
  experiments, 
  wine- 
  traps 
  were 
  used 
  as 
  indicators. 
  

   They 
  were 
  placed 
  in 
  position 
  on 
  the 
  28th 
  April 
  1913, 
  and 
  the 
  first 
  

   few 
  captures 
  early 
  in 
  May 
  were 
  disregarded, 
  as 
  some 
  few 
  individuals 
  

   always 
  emerge 
  prematurely. 
  About 
  the 
  16th 
  May 
  catches 
  began 
  to 
  

   become 
  abundant 
  and 
  this 
  date 
  was 
  used 
  as 
  a 
  basis, 
  the 
  first 
  appUcation 
  

   of 
  spray 
  being 
  made 
  three 
  weeks 
  later 
  on 
  the 
  6th 
  June. 
  This 
  was 
  

   followed 
  by 
  a 
  second 
  apphcation 
  ten 
  days 
  later, 
  on 
  the 
  16th 
  June. 
  

   The 
  mortality 
  on 
  the 
  treated 
  portion 
  of 
  the 
  plot 
  reached 
  94-2 
  per 
  cent. 
  

   in 
  the 
  case 
  of 
  Chenin 
  hlanc 
  vines 
  and 
  68*0 
  per 
  cent, 
  in 
  the 
  case 
  of 
  

   Gamay 
  vines. 
  This 
  proves 
  that 
  the 
  Gamay, 
  a 
  vine 
  of 
  rapid 
  growth, 
  

   requires 
  a 
  different 
  date 
  of 
  treatment 
  from 
  the 
  Chenin 
  hlanc. 
  In 
  a 
  

   vineyard 
  where 
  many 
  different 
  species 
  of 
  vine 
  are 
  grown 
  the 
  grower 
  

   has 
  a 
  longer 
  period 
  at 
  his 
  disposal 
  in 
  which 
  to 
  apply 
  treatment. 
  The 
  

   author 
  states 
  that 
  four 
  labourers, 
  experienced 
  in 
  this 
  work, 
  can 
  cover 
  

   2| 
  acres 
  in 
  a 
  day, 
  if 
  both 
  sides 
  of 
  each 
  row 
  of 
  stocks 
  be 
  carefully 
  

   sprayed. 
  This 
  is 
  for 
  the 
  first 
  appUcation 
  ; 
  the 
  second 
  one 
  requires 
  

   a 
  Uttle 
  less 
  time. 
  This 
  means 
  that 
  in 
  favourable 
  weather 
  and 
  using 
  

   the 
  plant 
  now 
  available, 
  four 
  men 
  can 
  thoroughly 
  spray 
  a 
  vineyard 
  

   of 
  16 
  acres 
  planted 
  with 
  four 
  different 
  species 
  of 
  vines. 
  For 
  instance 
  

   the 
  following 
  species 
  of 
  vines 
  should 
  be 
  sprayed 
  in 
  the 
  order 
  given 
  : 
  — 
  • 
  

   Pinot 
  Chardonnay, 
  Gamay, 
  Cabernet 
  Sauvignon 
  and, 
  lastly, 
  Chenin 
  

   hlanc. 
  Even 
  in 
  this 
  case 
  a 
  few 
  days 
  would 
  still 
  remain 
  over 
  in 
  the 
  

   interval 
  between 
  the 
  first 
  and 
  second 
  treatments, 
  so 
  that 
  the 
  first 
  

   treatment 
  might 
  be 
  postponed 
  a 
  couple 
  of 
  days 
  in 
  case 
  of 
  wet 
  weather. 
  

   It 
  should 
  be 
  noted 
  that 
  when 
  rain 
  falls 
  some 
  hours 
  after 
  spraying 
  is 
  

   completed, 
  the 
  spray 
  has 
  had 
  time 
  to 
  dry 
  and 
  is 
  not 
  easily 
  washed 
  

   away 
  or 
  rendered 
  ineffective. 
  In 
  vineyards 
  that 
  are 
  surrounded 
  by 
  

   others 
  it 
  is 
  necessary 
  to 
  practise 
  control 
  against 
  the 
  second 
  generation 
  

   of 
  Clysia 
  if 
  the 
  benefit 
  due 
  to 
  the 
  above 
  treatment 
  is 
  to 
  be 
  reaped. 
  

   Insecticide 
  sprays 
  are 
  impracticable 
  and 
  recourse 
  must 
  be 
  had 
  to 
  

   insectifuge 
  powders. 
  Seven 
  appUcations 
  are 
  theoretically 
  necessary. 
  

   They 
  should 
  be 
  made 
  during 
  the 
  flight 
  of 
  the 
  moths, 
  at 
  intervals 
  of 
  

   four 
  days, 
  beginning 
  on 
  the 
  17th 
  July. 
  The 
  powder 
  is 
  made 
  up 
  of 
  

   one- 
  third 
  precipitated 
  sulphur 
  and 
  two-thirds 
  hydraulic 
  Ume. 
  In 
  

   actual 
  practice 
  only 
  three 
  or 
  four 
  appUcations 
  are 
  usually 
  possible, 
  

   but 
  they 
  will 
  give 
  satisfactory 
  results 
  if 
  made 
  during 
  the 
  period 
  of 
  

   maximum 
  intensity 
  of 
  flight. 
  The 
  foregoing 
  mixture 
  has 
  been 
  proved 
  

   to 
  be 
  efficacious 
  against 
  Clysia 
  ; 
  it 
  is 
  cheap 
  and 
  is 
  also 
  of 
  use 
  against 
  

   Oidium 
  and 
  other 
  pests 
  which 
  appear 
  in 
  July. 
  The 
  combination 
  of 
  

   the 
  insecticide 
  sprays 
  and 
  insectifuge 
  dusting 
  reduced 
  the 
  percentage 
  

   of 
  injury 
  by 
  60*8, 
  whereas 
  dusting 
  alone 
  only 
  reduced 
  the 
  percentage 
  

   by 
  26-3. 
  The 
  author 
  believes 
  that 
  the 
  powders 
  act 
  by 
  impeding 
  

  

  