﻿46 
  

  

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

  

  cause 
  early 
  in 
  the 
  spring 
  the 
  young 
  

   worms 
  burrow 
  into 
  the 
  tender 
  ter- 
  

   minal 
  growth 
  of 
  the 
  trees 
  and 
  

   cause 
  the 
  rapidly 
  growing 
  twigs 
  

   to 
  wilt 
  (fig. 
  54) 
  . 
  In 
  this 
  way 
  they 
  

  

  \ 
  

  

  >'t£^ 
  

  

  Figure 
  54. 
  — 
  Peach 
  shoot 
  injured 
  by 
  the 
  

   peach 
  twig 
  borer. 
  

  

  interfere 
  with 
  the 
  development 
  of 
  

   new 
  growth. 
  Their 
  presence 
  in 
  

   the 
  peaches 
  causes 
  a 
  direct 
  loss 
  of 
  

   fruit. 
  The 
  peach 
  twig 
  borer 
  also 
  

   attacks 
  prune 
  and 
  apricot 
  trees, 
  

   and 
  the 
  twig 
  injury 
  is 
  especially 
  

   serious 
  on 
  nursery 
  trees 
  or 
  in 
  

   young 
  orchards. 
  The 
  species 
  

   originated 
  in 
  Europe 
  and 
  has 
  been 
  

   in 
  the 
  United 
  States 
  for 
  many 
  

   years. 
  

  

  LIFE 
  HISTORY 
  

  

  The 
  young 
  peach 
  twig 
  borers 
  

   winter 
  in 
  small 
  silk-lined 
  burrows, 
  

   known 
  as 
  hibernacula, 
  in 
  the 
  bark. 
  

   These 
  are 
  usually 
  constructed 
  in 
  

   the 
  folded 
  bark 
  found 
  in 
  the 
  

   crotches 
  of 
  the 
  younger 
  branches. 
  

   Each 
  burrow 
  has 
  a 
  characteristic 
  

   projecting 
  tube 
  or 
  "chimney," 
  

  

  composed 
  of 
  silk 
  and 
  tiny 
  pieces 
  

   of 
  bark, 
  which 
  is 
  difficult 
  to 
  see 
  

   without 
  a 
  lens. 
  The 
  small 
  worms 
  

   leave 
  these 
  winter 
  quarters 
  as 
  soon 
  

   as 
  twig 
  growth 
  has 
  begun 
  and 
  bur- 
  

   row 
  into 
  the 
  new 
  shoots, 
  where 
  

   they 
  feed 
  on 
  the 
  pith 
  and 
  inner 
  

   bark 
  and 
  cause 
  the 
  shoot 
  to 
  wilt. 
  

   Frequently 
  a 
  single 
  worm 
  injures 
  

   several 
  twigs 
  in 
  this 
  manner. 
  

  

  By 
  May 
  the 
  worms 
  are 
  mature, 
  

   nearly 
  one-half 
  inch 
  long, 
  and 
  red- 
  

   dish 
  brown. 
  They 
  spin 
  loose 
  co- 
  

   coons 
  in 
  rough 
  places 
  in 
  the 
  bark 
  

   or 
  in 
  curled 
  leaves, 
  and 
  the 
  small, 
  

   inconspicuous, 
  grayish 
  m 
  o 
  t 
  h 
  s 
  

   emerge 
  in 
  June. 
  These 
  lay 
  minute 
  

   eggs 
  on 
  the 
  bark, 
  and 
  the 
  tiny 
  

   worms 
  hatching 
  from 
  them 
  attack 
  

   the 
  fruit 
  as 
  well 
  as 
  the 
  new 
  growth. 
  

   They 
  usually 
  burrow 
  into 
  the 
  

   peaches 
  near 
  the 
  stem 
  end 
  and 
  feed 
  

   around 
  the 
  pit; 
  or, 
  if 
  this 
  is 
  still 
  

   soft, 
  they 
  enter 
  it 
  and 
  feed 
  on 
  the 
  

   kernel. 
  This 
  second 
  brood 
  of 
  

   worms 
  also 
  produces 
  a 
  brood 
  of 
  

   moths 
  that 
  lay 
  eggs, 
  and 
  the 
  young 
  

   worms 
  hatching 
  from 
  these 
  eggs 
  

   build 
  the 
  silken 
  burrows 
  in 
  which 
  

   the 
  winter 
  is 
  spent. 
  

  

  CONTROL 
  

  

  The 
  peach 
  twig 
  borer 
  is 
  easily 
  

   controlled 
  on 
  peaches 
  with 
  appli- 
  

   cations 
  of 
  liquid 
  lime-sulfur 
  as 
  

   used 
  for 
  the 
  San 
  Jose 
  scale 
  (p. 
  6) 
  , 
  

   but 
  this 
  material 
  may 
  be 
  injurious 
  

   to 
  apricots. 
  If 
  there 
  is 
  no 
  scale 
  

   infestation, 
  a 
  dilution 
  testing 
  31/2° 
  

   Baume 
  is 
  adequate 
  (table 
  1, 
  p. 
  60) 
  

   and 
  may 
  be 
  applied 
  at 
  any 
  time 
  in 
  

   the 
  spring 
  before 
  the 
  pink 
  stage 
  of 
  

   the 
  blossom 
  buds. 
  Oil 
  sprays 
  at 
  

   this 
  time 
  are 
  much 
  less 
  effective 
  

   and 
  should 
  not 
  be 
  used 
  if 
  the 
  twig 
  

   borer 
  is 
  at 
  all 
  serious. 
  Sprays 
  con- 
  

   taining 
  3 
  pounds 
  of 
  basic 
  lead 
  

   arsenate 
  to 
  100 
  gallons, 
  or 
  nicotine 
  

   sulfate 
  at 
  three-fourths 
  pint 
  to 
  100 
  

   gallons 
  of 
  water, 
  with 
  soap 
  or 
  

   spreader, 
  are 
  also 
  effective 
  if 
  used 
  

   before 
  the 
  trees 
  are 
  in 
  full 
  bloom. 
  

  

  