﻿20 
  

  

  CIRCULAR 
  2 
  70, 
  U. 
  S. 
  DEPARTMEXT 
  OF 
  AGRICULTURE 
  

  

  Figure 
  23. 
  — 
  Treehoppers: 
  A, 
  Buffalo 
  tree- 
  

   hopper; 
  B, 
  green 
  clover 
  treehopper; 
  C, 
  

   dark-colored 
  treehopper. 
  Enlarged. 
  

  

  trees 
  are 
  most 
  often 
  attacked. 
  

   Frequently 
  the 
  gTowth 
  of 
  such 
  

   trees 
  is 
  seriously 
  retarded. 
  Injury 
  

   is 
  practically 
  confined 
  to 
  the 
  cur- 
  

   rent 
  season's 
  growth 
  and 
  to 
  

   1-year-old 
  wood, 
  but 
  the 
  old 
  scars 
  

   persist 
  for 
  some 
  3^ears. 
  Apple 
  and 
  

   pear 
  trees 
  are 
  the 
  most 
  subject 
  to 
  

   injury, 
  although 
  peach, 
  cherry. 
  

  

  plum, 
  and 
  quince 
  

   occasionally. 
  

  

  are 
  affected 
  

  

  LIFE 
  HISTORY 
  

  

  The 
  whitish, 
  cylindrical 
  eggs 
  of 
  

   the 
  treehoppers 
  are 
  about 
  one- 
  

   tenth 
  inch 
  long, 
  and 
  from 
  6 
  to 
  20 
  

   of 
  them 
  are 
  placed 
  side 
  b}^ 
  side 
  

   in 
  each 
  slit, 
  the 
  ends 
  usually 
  being 
  

   yisible. 
  They 
  are 
  deposited 
  from 
  

   July 
  to 
  September 
  and 
  hatch 
  the 
  

   following 
  April 
  or 
  Ma}'. 
  The 
  

   young, 
  or 
  nymphs, 
  drop 
  to 
  the 
  

   ground 
  and 
  feed 
  chiefly 
  on 
  alfalfa, 
  

   where 
  they 
  are 
  most 
  often 
  found 
  

  

  in 
  the 
  center 
  of 
  the 
  crowns. 
  

   Growth 
  is 
  completed 
  in 
  July. 
  The 
  

   adults 
  are 
  about 
  three-eighths 
  

   inch 
  long, 
  grayish 
  or 
  greenish, 
  

   and 
  triangular, 
  and 
  the 
  commoner 
  

   species 
  haye 
  projecting 
  pronotal 
  

   horns, 
  suggesting 
  the 
  appearance 
  

   of 
  a 
  buffalo. 
  

  

  CONTROL 
  

  

  Clean 
  cultiyation 
  is 
  the 
  most 
  

   obyious 
  and 
  practical 
  control 
  

   method 
  and 
  should 
  be 
  practiced 
  

   in 
  young 
  orchards 
  wheneyer 
  pos- 
  

   sible. 
  As 
  the 
  trees 
  become 
  older, 
  

   coyer 
  crops 
  may 
  be 
  planted, 
  for 
  

   the 
  injury 
  is 
  less 
  seyere 
  on 
  older 
  

   trees. 
  Many 
  of 
  the 
  worst-scarred 
  

   twigs 
  can 
  be 
  pruned 
  off 
  during 
  the 
  

   winter, 
  and 
  should 
  be 
  burned 
  to 
  

   destroy 
  the 
  eggs. 
  A 
  thorough 
  

   application 
  of 
  a 
  dormant 
  spray 
  

   containing 
  4 
  percent 
  of 
  lubricat- 
  

  

  Figure 
  24. 
  — 
  Apple 
  twig 
  scarred 
  by 
  green 
  

   clover 
  treehoppers 
  in 
  laying 
  eggs. 
  

  

  