﻿24 
  

  

  CIRCULAR 
  2 
  7 
  0, 
  U. 
  S. 
  DEPARTMENT 
  OF 
  AGRICULTURE 
  

  

  with 
  the 
  wintering 
  eggs, 
  which 
  are 
  

   usually 
  laid 
  in 
  the 
  bark 
  of 
  wood 
  

   2 
  or 
  3 
  years 
  old. 
  The 
  eggs 
  hatch 
  

   in 
  April 
  or 
  May 
  : 
  and 
  the 
  young, 
  

   which 
  are 
  light 
  green 
  instead 
  of 
  

   white, 
  feed 
  in 
  the 
  same 
  manner 
  as 
  

   do 
  the 
  rose 
  leafhoppers. 
  The 
  

   green 
  adults 
  appear 
  in 
  May 
  and 
  

   June 
  and 
  some 
  are 
  still 
  present 
  in 
  

   July. 
  Most 
  of 
  the 
  eggs 
  are 
  de- 
  

   posited 
  in 
  June 
  and 
  July, 
  and 
  

   these 
  remain 
  in 
  the 
  bark 
  until 
  the 
  

   following 
  April. 
  As 
  it 
  has 
  only 
  

   a 
  single 
  generation 
  annually, 
  this 
  

   leaf 
  hopper 
  does 
  not 
  become 
  so 
  

   numerous 
  as 
  the 
  white 
  species. 
  

  

  CONTROL 
  

  

  The 
  standard 
  method 
  of 
  con- 
  

   trolling 
  leafhoppers 
  has 
  been 
  to 
  

   use 
  nicotine 
  sulfate, 
  one-half 
  pint 
  

   to 
  100 
  gallons, 
  together 
  with 
  an 
  

   oil 
  emulsion, 
  2 
  or 
  3 
  pounds 
  of 
  soap 
  

   dissolved 
  in 
  water, 
  or 
  other 
  type 
  

   of 
  spreader. 
  (See 
  Caution, 
  p. 
  

   60.) 
  DDT 
  controls 
  leafhoppers, 
  

   and 
  if 
  this 
  material 
  is 
  used 
  for 
  con- 
  

   trolling 
  other 
  pests 
  special 
  appli- 
  

   cations 
  against 
  leafhoppers 
  will 
  be 
  

   unnecessary. 
  It 
  is 
  best 
  to 
  spray 
  

   the 
  trees 
  when 
  the 
  young 
  are 
  on 
  

   them, 
  as 
  the 
  adults 
  are 
  too 
  active 
  to 
  

   be 
  reached 
  with 
  a 
  contact 
  spray. 
  

   The 
  application 
  should 
  therefore 
  

   be 
  made 
  in 
  May 
  for 
  control 
  of 
  the 
  

   green 
  leaf 
  hopper 
  or 
  the 
  first 
  gen- 
  

   eration 
  of 
  the 
  rose 
  leaf 
  hopper, 
  and 
  

   in 
  late 
  July 
  or 
  August 
  for 
  the 
  

   second 
  generation 
  of 
  the 
  latter. 
  

   The 
  lime-sulfur 
  spray, 
  which 
  is 
  

   used 
  in 
  May 
  in 
  some 
  districts 
  for 
  

   apple 
  scab 
  or 
  powdery 
  mildew, 
  

   constitutes 
  an 
  excellent 
  control 
  for 
  

   leafhoppers, 
  and 
  when 
  it 
  is 
  used 
  

   other 
  sprays 
  should 
  not 
  be 
  needed. 
  

  

  Syneta 
  Leaf 
  Beetle 
  

  

  The 
  syneta 
  leaf 
  beetle 
  seldom 
  in- 
  

   jures 
  apples, 
  but 
  may 
  reduce 
  the 
  

   pear 
  crop 
  by 
  50 
  percent 
  or 
  more. 
  

   The 
  injury 
  consists 
  of 
  scars 
  and 
  

   deformities 
  on 
  the 
  fruit 
  caused 
  by 
  

   the 
  beetles 
  when 
  feeding. 
  The 
  

  

  beetle 
  also 
  chews 
  the 
  fruit 
  stems 
  

   (fig. 
  30), 
  and 
  causes 
  some 
  of 
  the 
  

   fruit 
  to 
  drop. 
  Practically 
  all 
  the 
  

   injury 
  is 
  done 
  during 
  April 
  and 
  

   May. 
  The 
  life 
  history 
  of 
  the 
  beetle 
  

   is 
  discussed 
  on 
  page 
  34. 
  

  

  Figure 
  30. 
  — 
  Young 
  pears 
  injured 
  by 
  the 
  

   syneta 
  leaf 
  beetle. 
  

  

  CONTROL 
  

  

  Beetles 
  on 
  apples 
  and 
  pears 
  may 
  

   often 
  be 
  controlled 
  by 
  a 
  single 
  

   thorough 
  application 
  of 
  lead 
  

   arsenate, 
  3 
  pounds 
  to 
  100 
  gallons 
  

   of 
  water, 
  used 
  as 
  a 
  calyx 
  spray. 
  If 
  

   the 
  infestation 
  is 
  severe, 
  a 
  second 
  

   application 
  may 
  be 
  made 
  10 
  days 
  

   or 
  2 
  weeks 
  later. 
  Dusts 
  containing 
  

   30 
  percent 
  of 
  lead 
  arsenate 
  or 
  5 
  

   percent 
  of 
  DDT 
  are 
  also 
  effective. 
  

  

  Western 
  Tent 
  Caterpillar 
  

  

  The 
  western 
  tent 
  caterpillar 
  is 
  

   practically 
  limited 
  in 
  its 
  depreda- 
  

   tions 
  to 
  the 
  region 
  west 
  of 
  the 
  Cas- 
  

   cade 
  Mountains. 
  The 
  caterpillars 
  

   appear 
  in 
  May 
  and 
  June, 
  con- 
  

   structing 
  tents 
  of 
  webbing 
  in 
  the 
  

   crotches 
  or 
  about 
  the 
  smaller 
  

   twigs 
  and 
  leaves 
  of 
  the 
  trees. 
  The 
  

   tents 
  are 
  similar 
  to 
  those 
  of 
  the 
  

   eastern 
  tent 
  caterpillar 
  shown 
  in 
  

   figure 
  31. 
  The 
  caterpillars 
  feed 
  

   voraciously 
  during 
  the 
  day, 
  de- 
  

  

  