﻿THE 
  FRUIT-TREE 
  LEAP-ROLLER. 
  107 
  

  

  estimated 
  that 
  the 
  tobacco 
  mixture 
  applied 
  May 
  2 
  and 
  3 
  destroyed 
  

   about 
  50 
  per 
  cent 
  of 
  the 
  worms 
  then 
  on 
  the 
  trees. 
  Plat 
  III, 
  which 
  

   received 
  two 
  applications 
  of 
  the 
  combination 
  spray, 
  showed 
  no 
  better 
  

   results 
  than 
  on 
  Plat 
  IV, 
  which 
  received 
  only 
  arsenate 
  of 
  lead 
  for 
  the 
  

   second 
  treatment. 
  Plat 
  VI 
  (Paris 
  green 
  alone) 
  showed 
  a 
  slight 
  

   improvement 
  over 
  Plats 
  I 
  (arsenate 
  of 
  lead 
  3 
  :50) 
  and 
  II 
  (arsenate 
  of 
  

   lead 
  3:50 
  plus 
  4 
  ounces 
  Paris 
  green). 
  Plat 
  V, 
  which 
  was 
  sprayed 
  

   with 
  arsenate 
  of 
  zinc 
  at 
  the 
  rate 
  of 
  1 
  pound 
  to 
  50 
  gallons 
  of 
  water, 
  

   gave 
  disappointing 
  results, 
  as 
  it 
  not 
  only 
  failed 
  to 
  destroy 
  the 
  larvae 
  

   in 
  goodly 
  numbers 
  but 
  it 
  seriously 
  burned 
  the 
  foliage. 
  The 
  arsenical 
  

   injury 
  to 
  the 
  foliage 
  could, 
  however, 
  have 
  been 
  prevented 
  if 
  lime 
  

   had 
  been 
  added. 
  An 
  increased 
  strength 
  of 
  this 
  arsenical 
  would 
  no 
  

   doubt 
  have 
  been 
  more 
  effective. 
  On 
  Plats 
  VII, 
  VIII, 
  and 
  IX, 
  where 
  

   40 
  per 
  cent 
  nicotine 
  solution 
  alone 
  was 
  used, 
  the 
  benefit 
  from 
  spray- 
  

   ing 
  was 
  considerably 
  less. 
  Plat 
  VII 
  of 
  these 
  plats 
  gave 
  the 
  best 
  

   results. 
  On 
  the 
  day 
  after 
  the 
  spraying, 
  by 
  carefully 
  counting 
  the 
  

   number 
  of 
  dead 
  larvae 
  as 
  compared 
  with 
  the 
  living 
  ones 
  found 
  on 
  the 
  

   trees, 
  it 
  was 
  found 
  that 
  about 
  55 
  per 
  cent 
  of 
  the 
  larvae 
  were 
  killed 
  

   by 
  the 
  spray. 
  On 
  Plats 
  VIII 
  and 
  IX 
  not 
  more 
  than 
  25 
  per 
  cent 
  of 
  

   the 
  larvae 
  were 
  killed. 
  These 
  plats, 
  however, 
  were 
  sprayed 
  a 
  week 
  

   later 
  than 
  Plat 
  VII, 
  and 
  the 
  difference 
  in 
  results 
  was 
  probably 
  due 
  

   to 
  the 
  fact 
  that 
  the 
  worms 
  at 
  that 
  time 
  were 
  more 
  resistant 
  to 
  the 
  

   tobacco 
  mixture 
  and 
  that 
  it 
  was 
  much 
  more 
  difficult 
  to 
  reach 
  them 
  

   in 
  the 
  rolled-up 
  leaves. 
  

  

  It 
  will 
  be 
  noted 
  in 
  comparing 
  the 
  sprayed 
  plats 
  with 
  the 
  unsprayed 
  

   plat 
  as 
  to 
  the 
  amount 
  of 
  injury 
  to 
  the 
  fruit 
  alone 
  that 
  there 
  is 
  much 
  

   in 
  favor 
  of 
  spraying. 
  The 
  benefit 
  for 
  each 
  plat 
  over 
  the 
  check 
  plat 
  

   is 
  shown 
  in 
  percentages 
  as 
  follows: 
  Plat 
  I, 
  78; 
  Plat 
  II, 
  78; 
  Plat 
  III, 
  

   83; 
  Plat 
  IV, 
  83; 
  Plat 
  V, 
  73; 
  Plat 
  VI, 
  80; 
  Plat 
  VII, 
  73; 
  Plat 
  VIII, 
  

   83; 
  Plat 
  IX, 
  83. 
  The 
  difference 
  in 
  condition 
  of 
  foliage 
  must 
  not 
  be 
  

   lost 
  sight 
  of 
  in 
  determining 
  the 
  benefit 
  of 
  spraying. 
  The 
  check 
  trees 
  

   were 
  practically 
  defoliated, 
  while 
  the 
  sprayed 
  trees 
  retained 
  their 
  

   foliage 
  throughout 
  the 
  season 
  and 
  were 
  enabled 
  to 
  develop 
  fruit 
  buds 
  

   for 
  the 
  following 
  season. 
  

  

  Although 
  there 
  is 
  much 
  in 
  favor 
  of 
  spraying 
  with 
  arsenicals, 
  alone 
  

   or 
  in 
  combination 
  with 
  tobacco, 
  they 
  have 
  not 
  given 
  entire 
  satisfaction. 
  

  

  LIGHT 
  TRAPS. 
  

  

  The 
  writer 
  had 
  occasion 
  to 
  observe 
  many 
  lights 
  used 
  as 
  traps 
  to 
  

   catch 
  the 
  moths 
  of 
  the 
  leaf 
  -roller 
  at 
  Canon 
  City, 
  Colo., 
  during 
  the 
  

   season 
  of 
  1912. 
  The 
  use 
  of 
  these 
  traps 
  was 
  not 
  advocated, 
  but 
  many 
  

   orchardists 
  were 
  of 
  the 
  opinion 
  that 
  a 
  decided 
  benefit 
  would 
  be 
  

   derived 
  if 
  enough 
  lights 
  were 
  placed 
  in 
  the 
  orchard, 
  as 
  the 
  moths 
  

   were 
  very 
  readily 
  attracted 
  to 
  them. 
  Such 
  orchards 
  were 
  examined 
  

  

  