﻿ORCHAED 
  INSECTS 
  PACIFIC 
  NORTHWEST 
  

  

  51 
  

  

  are 
  treated 
  with 
  a 
  10-percent 
  dust 
  

   early 
  in 
  the 
  spring 
  before 
  the 
  bugs 
  

   have 
  started 
  feeding, 
  damage 
  

   should 
  be 
  avoided. 
  Both 
  the 
  

   ground 
  and 
  the 
  trees 
  should 
  be 
  

   dusted 
  at 
  the 
  rate 
  of 
  about 
  40 
  

   pounds 
  per 
  acre. 
  This 
  treatment 
  

   may 
  result 
  in 
  an 
  increase 
  of 
  

   orchard 
  mites. 
  

  

  ^^^^^'"^ 
  

  

  I 
  

  

  Figure 
  61,- 
  

  

  -Trunk 
  of 
  tree 
  injured 
  by 
  the 
  

   shot-hole 
  borer. 
  

  

  Shot-Hole 
  Borers 
  

  

  Two 
  

  

  kinds 
  of 
  shot-hole 
  borers 
  

   occur 
  throughout 
  the 
  Pacific 
  

   Northwest. 
  They 
  attack 
  the 
  wood 
  

   of 
  all 
  the 
  clecidous 
  fruit 
  trees 
  (fig. 
  

   61) 
  preferring 
  wood 
  that 
  is 
  in 
  an 
  

   unhealthy 
  or 
  dying 
  condition, 
  

  

  brought 
  about 
  by 
  mechanical 
  or 
  

   winter 
  injury, 
  improper 
  watering, 
  

   or 
  insects 
  or 
  fungus 
  diseases. 
  

   They 
  will 
  also 
  attack 
  the 
  larger 
  

   wood 
  that 
  has 
  been 
  pruned 
  from 
  

   trees, 
  at 
  least 
  until 
  it 
  has 
  dried 
  out 
  

   thoroughly. 
  They 
  seem 
  to 
  be 
  par- 
  

   ticularly 
  attracted 
  to 
  the 
  souring 
  

   sap, 
  but 
  under 
  some 
  conditions 
  

   they 
  will 
  attack 
  healthy 
  wood. 
  

   The 
  beetles 
  bore 
  into 
  the 
  sapwood 
  

   and 
  make 
  tunnels 
  through 
  it 
  in 
  

   which 
  they 
  lay 
  eggs. 
  The 
  souring 
  

   sap 
  favors 
  the 
  growth 
  of 
  a 
  fungus, 
  

   and 
  the 
  young 
  grubs 
  feed 
  on 
  this 
  

   fungus 
  and 
  not 
  on 
  the 
  wood. 
  

   There 
  are 
  two 
  broods 
  a 
  year. 
  In 
  

   the 
  fall 
  the 
  grubs 
  of 
  the 
  second 
  

   brood 
  transform 
  to 
  beetles, 
  which 
  

   remain 
  in 
  the 
  tunnels 
  until 
  spring, 
  

   when 
  they 
  emerge 
  and 
  construct 
  

   fresh 
  tunnels. 
  If 
  the 
  tunnels 
  are 
  

   numerous, 
  the 
  growth 
  of 
  the 
  trees 
  

   may 
  be 
  affected 
  seriously. 
  The 
  

   beetle 
  is 
  sometimes 
  found 
  attack- 
  

   ing 
  the 
  heartwood 
  also. 
  On 
  

   healthy 
  trees, 
  the 
  attack 
  often 
  

   takes 
  place 
  just 
  below 
  a 
  bud, 
  which 
  

   is 
  weakened 
  and 
  killed, 
  even 
  

   though 
  the 
  beetle 
  may 
  be 
  repelled 
  

   by 
  a 
  flow 
  of 
  sap 
  before 
  it 
  has 
  been 
  

   able 
  to 
  deposit 
  eggs. 
  

  

  To 
  prevent 
  attacks 
  of 
  this 
  beetle, 
  

   the 
  trees 
  should 
  be 
  kept 
  in 
  a 
  

   healthy 
  vigorous 
  condition; 
  if 
  

   they 
  are 
  unhealthy, 
  the 
  cause 
  

   should 
  be 
  determined 
  and 
  cor- 
  

   rected 
  if 
  possible. 
  A 
  spray 
  made 
  

   with 
  2 
  pounds 
  of 
  50-percent 
  DDT 
  

   wettable 
  powder, 
  or 
  1 
  pound 
  of 
  15- 
  

   percent 
  parathion 
  wettable 
  pow- 
  

   der, 
  in 
  100 
  gallons 
  of 
  water, 
  when 
  

   the 
  beetles 
  become 
  active, 
  usually 
  

   in 
  late 
  May 
  and 
  again 
  in 
  Septem- 
  

   ber, 
  will 
  prevent 
  damage. 
  (See 
  

   Caution, 
  p. 
  59.) 
  

  

  Peach 
  Tree 
  Borers 
  

  

  Although 
  peach 
  tree 
  borers 
  are 
  

   serious 
  pests 
  of 
  peach 
  trees 
  in 
  Cali- 
  

   fornia 
  and 
  the 
  Eastern 
  States, 
  they 
  

   do 
  more 
  injury 
  to 
  prune 
  trees 
  than 
  

   to 
  peach 
  trees 
  in 
  the 
  Pacific 
  North- 
  

  

  