﻿84 
  

  

  DECIDUOUS 
  FRUIT 
  INSECTS 
  AND 
  INSECTICIDES. 
  

   Experiment 
  II. 
  

  

  In 
  order 
  to 
  obtain 
  further 
  data 
  on 
  the 
  killing 
  effect 
  of 
  lime-sulphur 
  

   another 
  experiment 
  was 
  started 
  July 
  30, 
  using 
  different 
  strengths 
  of 
  

   lime-sulphur 
  as 
  given 
  in 
  Table 
  II. 
  

  

  Table 
  II. 
  — 
  Tests 
  of 
  the 
  killing 
  effect 
  of 
  lime-sulphur 
  on 
  the 
  fall 
  webworm. 
  

   [Experiment 
  started 
  July 
  30, 
  1912, 
  Benton 
  Harbor, 
  Mich.; 
  20 
  larvae 
  in 
  each 
  lot.] 
  

  

  

  Larvae 
  dying 
  in 
  each 
  lot- 
  

  

  Date 
  of 
  

   examination. 
  

  

  Larvae 
  dying 
  in 
  each 
  lot. 
  

  

  Date 
  of 
  

   examination. 
  

  

  Lot 
  

   1— 
  

  

  Check 
  

   (un- 
  

  

  spray- 
  

   ed). 
  

  

  Lot 
  

   2— 
  

   Lime- 
  

   sul- 
  

   phur, 
  

   1J-50. 
  

  

  Lot 
  

   3— 
  

   Lime- 
  

   sul- 
  

   phur, 
  

   3-50. 
  

  

  Lot 
  

   4— 
  

   Lime- 
  

   sul- 
  

   phur, 
  

   6-50. 
  

  

  Lot 
  

   5i— 
  

   Arse- 
  

   nate 
  

  

  of 
  

   lead, 
  

   2-50. 
  

  

  Lot 
  

   1-r- 
  

  

  Check 
  

   (un- 
  

  

  spray- 
  

   ed). 
  

  

  Lot 
  

   2— 
  

   Lime- 
  

   sul- 
  

   phur, 
  

   H-50. 
  

  

  Lot 
  

   3— 
  

   Lime- 
  

   sul- 
  

   phur, 
  

   3-50. 
  

  

  Lot 
  

   4— 
  

   Lime- 
  

   sul- 
  

   phur, 
  

   6-50. 
  

  

  Lot 
  

  

  51— 
  

   Arse- 
  

   nate 
  

   of 
  

   lead, 
  

   2-50. 
  

  

  

  

  

  

  

  

  Aug. 
  14.... 
  

  

  

  2 
  

  

  

  

  

  2 
  

  

  

  

  

  

  

  15 
  

  

  

  

  

  

  3 
  

  

  

  2 
  

  

  

  

  

  20 
  

  

  

  

  

  

  

  4 
  

  

  

  1 
  

   1 
  

  

  3 
  

   5 
  

   3 
  

  

  8 
  

  

  6 
  

  

  ""u 
  

  

  25 
  

  

  

  

  

  

  

  5 
  

  

  

  1 
  

  

  29 
  

  

  

  

  

  

  

  § 
  

  

  

  Total 
  num- 
  

   ber 
  dead 
  . 
  . 
  

   Number 
  days 
  re- 
  

   quired 
  to 
  kill 
  

  

  

  

  

  

  

  7 
  

  

  1 
  

  

  1 
  

  

  3 
  

   2 
  

   2 
  

   4 
  

   1 
  

   2 
  

  

  9 
  

  

  4 
  

   4 
  

  

  1 
  

  

  20 
  

  

  15 
  

  

  1.21 
  

  

  20 
  

  

  12 
  

  

  0.65 
  

  

  20 
  

  

  9 
  

  

  0.34 
  

  

  

  8 
  

  

  20 
  

  

  9 
  

  

  

  

  10 
  

  

  

  

  

  9 
  

  

  11 
  

  

  

  1 
  

  

  

  

  Square 
  inches 
  foli- 
  

   age 
  consumed 
  . 
  . 
  . 
  

  

  40.00 
  

  

  

  12 
  

  

  

  

  

  0.83 
  

  

  13 
  

  

  

  

  

  

  

  

  

  

  

  

  i 
  Arsenate 
  of 
  lead 
  was 
  used 
  in 
  lot 
  5 
  for 
  comparison 
  with 
  the 
  lime-sulphur 
  solution 
  

  

  In 
  this 
  experiment 
  15 
  days 
  were 
  required 
  by 
  lime-sulphur, 
  1^-50, 
  

   to 
  kill 
  the 
  20 
  larvae, 
  as 
  against 
  9 
  days 
  required 
  by 
  arsenate 
  of 
  lead, 
  

   2-50. 
  Twelve 
  days 
  were 
  required 
  by 
  lime-sulphur, 
  3-50, 
  while 
  lime- 
  

   sulphur, 
  6-50, 
  killed 
  the 
  20 
  larvae 
  in 
  the 
  same 
  length 
  of 
  time 
  required 
  

   by 
  arsenate 
  of 
  lead, 
  2-50. 
  The 
  check 
  lot 
  was 
  discontinued 
  at 
  the 
  

   end 
  of 
  30 
  days, 
  when 
  1 
  larva 
  was 
  recorded 
  dead 
  and 
  40 
  square 
  inches 
  

   of 
  foliage 
  consumed. 
  It 
  was 
  found 
  in 
  this 
  test 
  that 
  the 
  number 
  of 
  

   square 
  inches 
  of 
  foliage 
  consumed 
  decreased 
  about 
  one-half 
  as 
  the 
  

   strength 
  of 
  the 
  lime-sulphur 
  was 
  doubled, 
  the 
  largest 
  amount 
  being 
  

   1.21 
  square 
  inches. 
  The 
  amount 
  consumed 
  on 
  the 
  arsenate-of-lead 
  

   lot 
  was 
  0.83 
  of 
  a 
  square 
  inch. 
  

  

  Experiment 
  III. 
  

  

  In 
  Table 
  III 
  are 
  shown 
  the 
  comparative 
  results 
  of 
  a 
  dosage 
  test 
  

   consisting 
  of 
  seven 
  different 
  strengths 
  of 
  lime-sulphur 
  varying 
  from 
  

   J-50 
  to 
  6-50, 
  and 
  four 
  different 
  strengths 
  of 
  arsenate 
  of 
  lead 
  varying 
  

   from 
  i-50 
  to 
  5-50. 
  

  

  