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  of 
  these 
  four 
  years 
  of 
  defoliation 
  has 
  been 
  disastrous 
  to 
  the 
  trees 
  ; 
  they 
  

   have 
  now 
  a 
  stunted 
  appearance 
  and, 
  owing 
  to 
  growth 
  being 
  repeatedly 
  

   arrested, 
  they 
  have 
  many 
  dead 
  twigs 
  and 
  boughs. 
  The 
  species 
  in- 
  

   criminated 
  are 
  the 
  following 
  : 
  — 
  Phigalia 
  pilosaria, 
  Himera 
  'pennaria, 
  

   Hyhernia 
  defoliaria, 
  H. 
  aurantiaria, 
  Oporabia 
  dilutata, 
  Cheimatobia 
  

   boreata, 
  C. 
  brumata 
  and 
  Tortrix 
  viridana. 
  Insectivorous 
  birds 
  are 
  not 
  

   uncommon, 
  and 
  must 
  have 
  destroyed 
  large 
  numbers 
  of 
  the 
  larvae, 
  

   but 
  evidently 
  not 
  sufficient 
  to 
  keep 
  them 
  under 
  control. 
  

  

  Dew 
  (J. 
  A.). 
  Some 
  Properties 
  of 
  various 
  forms 
  of 
  Arsenate 
  of 
  Lead. 
  — 
  

  

  Jl. 
  Econ. 
  Entom., 
  Concord., 
  vii, 
  no. 
  2, 
  April 
  1914, 
  pp. 
  162-167. 
  

  

  The 
  present 
  paper 
  is 
  a 
  preliminary 
  report 
  of 
  the 
  work 
  done 
  by 
  the 
  

   author 
  during 
  the 
  past 
  year 
  to 
  determine 
  what 
  forms 
  of 
  arsenate 
  of 
  

   lead 
  are 
  the 
  most 
  effective, 
  and 
  what 
  characteristics 
  give 
  the 
  insecticide 
  

   its 
  value. 
  The 
  experiments 
  led 
  to 
  the 
  following 
  results 
  and 
  con- 
  

   clusions 
  : 
  The 
  lowest 
  number 
  of 
  units 
  of 
  AsgOg 
  necessary 
  to 
  give 
  an 
  

   effective 
  control 
  of 
  the 
  plum 
  curcuho 
  (Conotrachelus 
  nenuphar), 
  this 
  

   being 
  the 
  insect 
  experimented 
  on 
  throughout, 
  is 
  33. 
  One 
  pound 
  of 
  an 
  

   acid 
  arsenate 
  of 
  lead 
  (33 
  per 
  cent, 
  arsenic 
  oxide) 
  has 
  more 
  kilUng 
  power 
  

   than 
  a 
  pound 
  of 
  neutral 
  arsenate 
  of 
  lead 
  (25 
  per 
  cent.-27 
  per 
  cent, 
  

   arsenic 
  oxide), 
  and 
  each 
  has 
  more 
  kilHng 
  power 
  than 
  one 
  pound 
  of 
  

   basic 
  arsenate 
  of 
  lead 
  (20 
  per 
  cent, 
  arsenic 
  oxide). 
  Under 
  similar 
  

   climatic 
  conditions, 
  the 
  kilUng 
  power 
  of 
  an 
  acid 
  or 
  a 
  neutral 
  arsenate 
  

   of 
  lead 
  depends 
  directly 
  upon 
  the 
  percentage 
  of 
  arsenic 
  oxide 
  that 
  it 
  

   contains. 
  Basic 
  arsenate 
  of 
  lead, 
  under 
  the 
  chmatic 
  conditions 
  

   prevaiHng 
  while 
  the 
  experiments 
  were 
  being 
  carried 
  on, 
  became 
  too 
  

   slowly 
  available 
  to 
  give 
  good 
  results, 
  even 
  when 
  double 
  quantities 
  

   were 
  used. 
  When 
  used 
  in 
  accordance 
  with 
  the 
  spraying 
  practice 
  of 
  

   the 
  present 
  day, 
  all 
  trees 
  sprayed 
  with 
  these 
  different 
  forms 
  of 
  arsenate 
  

   of 
  lead 
  shed 
  a 
  comparatively 
  large 
  number 
  of 
  fruits 
  showing 
  no 
  insect 
  

   injury 
  ; 
  constant 
  characteristics 
  of 
  these 
  fruits 
  are 
  that 
  the 
  stems 
  

   remain 
  on 
  the 
  tree 
  and 
  the 
  fruits 
  show 
  a 
  sHght 
  shrivelHng 
  at 
  the 
  base. 
  

   The 
  number 
  of 
  these 
  shed 
  fruits 
  varies 
  with 
  the 
  form 
  of 
  arsenate 
  of 
  

   lead 
  used, 
  the 
  acid 
  forms 
  causing 
  the 
  greatest 
  percentage 
  of 
  loss 
  ; 
  

   i 
  t 
  is 
  independent 
  of 
  the 
  AsgO^ 
  content 
  of 
  the 
  spray. 
  

  

  Melander 
  (A. 
  L.). 
  Can 
  Insects 
  become 
  resistant 
  to 
  Sprays? 
  — 
  Jl. 
  Econ, 
  

   Entom., 
  Concord, 
  vii, 
  no. 
  2, 
  April 
  1914, 
  pp. 
  167-173. 
  

  

  Owing 
  to 
  a 
  prevalent 
  feeling 
  in 
  some 
  districts 
  that 
  the 
  lime-sulphur 
  

   spray 
  is 
  less 
  efficient 
  now 
  than 
  formally 
  in 
  controlling 
  San 
  Jose 
  scale, 
  

   it 
  has 
  been 
  suggested 
  that 
  it 
  is 
  possible 
  for 
  the 
  insect 
  to 
  become 
  immune 
  

   to 
  the 
  toxic 
  effects 
  of 
  the 
  spray. 
  For 
  several 
  years, 
  in 
  spite 
  of 
  every 
  

   precaution 
  having 
  been 
  taken 
  by 
  the 
  growers, 
  the 
  San 
  Jose 
  scale 
  has 
  

   been 
  increasingly 
  prevalent 
  in 
  the 
  Clarkston 
  Valley, 
  Washington. 
  

   This 
  led 
  the 
  authors 
  to 
  try 
  identical 
  solutions 
  in 
  a 
  number 
  of 
  locaUties, 
  

   and 
  to 
  make 
  bi-weekly 
  counts 
  of 
  the 
  proportion 
  of 
  Hving 
  and 
  dead 
  

   scales. 
  It 
  was 
  found 
  that 
  the 
  normal 
  action 
  of 
  the 
  Hme-sulphur 
  

   spray 
  is 
  continuous, 
  producing 
  complete 
  destruction 
  of 
  the 
  scale 
  in 
  

   a 
  little 
  more 
  than 
  a 
  month's 
  time. 
  In 
  the 
  Clarkston 
  experiment, 
  

   however, 
  from 
  4-13 
  per 
  cent., 
  or 
  more, 
  of 
  the 
  scales 
  were 
  aHve 
  

   six 
  weeks 
  after 
  the 
  spraying, 
  at 
  which 
  time 
  they 
  had 
  begun 
  their 
  

  

  