﻿ORCHARD 
  IXSECTS 
  PACIFIC 
  NORTHWEST 
  

  

  cade 
  Mountains. 
  It 
  is 
  readily 
  

   distinguishable 
  from 
  other 
  scale 
  

   insects 
  by 
  its 
  characteristic 
  shape 
  

   (fig. 
  6, 
  ^). 
  The 
  apple 
  is 
  a 
  favor- 
  

   ite 
  food 
  plant, 
  but 
  this 
  scale 
  also 
  

  

  Figure 
  6. 
  — 
  Oystershell 
  scale: 
  A, 
  Twig 
  en- 
  

   crusted 
  with 
  the 
  scale; 
  B, 
  old 
  scale 
  

   turned 
  over 
  to 
  show 
  eggs. 
  Enlarged. 
  

  

  lives 
  on 
  many 
  other 
  fruit 
  trees, 
  

   as 
  Avell 
  as 
  shade 
  trees, 
  ornamental 
  

   shrubs 
  and 
  plants, 
  and 
  on 
  native 
  

   trees, 
  such 
  as 
  willow 
  and 
  dog- 
  

   wood. 
  Its 
  effect 
  on 
  the 
  tree 
  and 
  

   fruit 
  is 
  similar 
  to 
  that 
  of 
  the 
  San 
  

  

  Jose 
  scale, 
  and 
  heavily 
  encrusted 
  

   trees 
  or 
  limbs 
  may 
  be 
  killed. 
  

  

  LIFE 
  HISTORY 
  

  

  If 
  the 
  old 
  scales 
  on 
  the 
  bark 
  are 
  

   turned 
  over 
  during 
  the 
  winter, 
  

   they 
  will 
  be 
  found 
  filled 
  with 
  

   small 
  pearly 
  white 
  eggs 
  (fig. 
  6, 
  

   B). 
  Often 
  there 
  are 
  nearly 
  100 
  

   eggs 
  beneath 
  a 
  single 
  scale. 
  The 
  

   eggs 
  hatch 
  shortly 
  after 
  the 
  apple 
  

   trees 
  bloom, 
  and 
  the 
  minute, 
  

   whitish 
  young 
  crawl 
  out 
  and 
  

   settle 
  in 
  a 
  few 
  hours 
  on 
  some 
  liv- 
  

   ing 
  part 
  of 
  the 
  plant. 
  They 
  de- 
  

   velop 
  slowly, 
  increasing 
  the 
  size 
  of 
  

   the 
  scale 
  covering 
  as 
  they 
  grow. 
  

   The 
  covering 
  of 
  the 
  female 
  is 
  

   about 
  one-eighth 
  inch 
  long 
  when 
  

   completed, 
  dark 
  brownish 
  gray, 
  

   and 
  shaped 
  somewhat 
  like 
  oyster- 
  

   shells. 
  The 
  covering 
  of 
  the 
  male 
  

   is 
  smaller 
  and 
  oval, 
  and 
  the 
  ma- 
  

   ture 
  males 
  emerge 
  from 
  the 
  scales 
  

   with 
  fully 
  developed 
  wings. 
  The 
  

   females 
  spend 
  their 
  entire 
  lives 
  

   beneath 
  the 
  scale 
  coverings, 
  de- 
  

   positing 
  eggs 
  under 
  them 
  in 
  the 
  

   fall 
  before 
  they 
  die. 
  

  

  CONTROL 
  

  

  The 
  dormant-season 
  applica- 
  

   tion 
  of 
  liquid 
  lime-sulfur 
  is 
  not 
  so 
  

   effective 
  against 
  the 
  oystershell 
  

   scale 
  as 
  against 
  the 
  San 
  Jose 
  scale. 
  

   However, 
  its 
  annual 
  use 
  keeps 
  

   this 
  scale 
  insect 
  in 
  check. 
  Oil 
  

   emulsions, 
  at 
  the 
  dilutions 
  recom- 
  

   mended 
  for 
  dormant 
  spraying 
  

   (p. 
  59), 
  are 
  more 
  effective 
  and 
  

   should 
  be 
  used 
  for 
  severe 
  infesta- 
  

   tions. 
  The 
  mixture 
  of 
  oil 
  emul- 
  

   sion 
  and 
  lime-sulfur 
  recommended 
  

   for 
  controlling 
  the 
  San 
  Jose 
  scale 
  

   (p. 
  6) 
  is 
  particularly 
  effective 
  

   against 
  the 
  oystershell 
  scale. 
  

  

  Cottony 
  Maple 
  Scale 
  

  

  The 
  cottony 
  maple 
  scale 
  some- 
  

   times 
  becomes 
  numerous 
  on 
  Winter 
  

   Nelis 
  and 
  Anjou 
  pear 
  trees, 
  but 
  it 
  

   does 
  not 
  seem 
  to 
  thrive 
  on 
  the 
  Bart- 
  

   lett 
  variety 
  and 
  is 
  seldom 
  seen 
  on 
  

  

  