﻿8 
  

  

  Accordiiii:^ 
  to 
  Prof. 
  J. 
  B. 
  Smith, 
  * 
  "Peach-trees 
  suffer 
  most 
  se- 
  

   verely, 
  and 
  succumb 
  iu 
  two 
  or 
  three 
  years. 
  Other 
  thin-barked 
  trees 
  

   come 
  next, 
  and 
  suffer 
  as 
  they 
  are 
  young, 
  or 
  offer 
  the 
  insects 
  oppor- 
  

   tunity 
  to 
  reach 
  tlie 
  inner 
  bark 
  layers 
  on 
  the 
  trunk 
  and 
  main 
  branches. 
  

   Pear-trees 
  suffer 
  worse 
  than 
  apples, 
  but 
  even 
  young 
  trees 
  may 
  live 
  

   on 
  under 
  scale 
  attack 
  for 
  several 
  years, 
  though 
  without 
  making 
  much 
  

   growth. 
  The 
  tree 
  gradually 
  becomes 
  hide-bound, 
  the 
  bark 
  wrinkles 
  

   and 
  splits 
  or 
  cracks, 
  and 
  in 
  that 
  event 
  the 
  tree 
  dies 
  down 
  from 
  the 
  

   top. 
  The 
  leaves 
  also 
  become 
  infested 
  and 
  the 
  scales 
  range 
  them- 
  

   selves 
  by 
  preference 
  on 
  each 
  side 
  of 
  the 
  midrib, 
  causing 
  a 
  stoppage 
  

   in 
  growth, 
  and 
  a 
  purplish 
  discoloration. 
  Scales 
  attached 
  to 
  fallen 
  

   leaves 
  are 
  doomed 
  to 
  death, 
  because 
  they 
  have 
  no 
  power 
  of 
  motion 
  

   and 
  must 
  starve 
  as 
  the 
  leaf 
  dries 
  or 
  decays. 
  Fruit 
  when 
  badly 
  in- 
  

   fested 
  becomes 
  distorted, 
  and 
  does 
  not 
  attain 
  its 
  full 
  growth." 
  

  

  EXTENSION 
  OF 
  RANGE 
  AND 
  DIMINUTION 
  OF 
  NUMBERS. 
  

  

  When 
  first 
  introduced 
  into 
  a 
  new 
  locality, 
  although 
  commonly 
  

   attacked 
  early 
  by 
  certain 
  insect 
  enemies, 
  this 
  scale 
  spreads 
  slowly 
  

   but 
  without 
  interruption, 
  more 
  or 
  less 
  rapidly 
  killing 
  the 
  fruit 
  trees 
  

   it 
  attacks, 
  continuing 
  for 
  several 
  years 
  at 
  least 
  a 
  course 
  of 
  unmiti- 
  

   gated 
  destruction. 
  The 
  effect 
  of 
  this 
  slow 
  spread 
  combined 
  with 
  its 
  

   rapid 
  rate 
  of 
  multiplication 
  and 
  the 
  consequent 
  concentration 
  of 
  vast 
  

   numbers 
  of 
  the 
  scale 
  upon 
  a 
  gradually 
  enlarging 
  area 
  is 
  to 
  cause 
  a 
  

   gradual 
  but 
  complete 
  destruction, 
  progressing 
  from 
  the 
  first 
  infested 
  

   center 
  outwards 
  over 
  all 
  fruit 
  trees 
  and 
  other 
  plants 
  especially 
  sub- 
  

   ject 
  to 
  its 
  attack. 
  An 
  entire 
  orchard, 
  no 
  matter 
  how 
  great 
  its 
  size, 
  

   may 
  thus 
  be 
  completely 
  ruined 
  as 
  by 
  an 
  incurable 
  disease. 
  It 
  is 
  

   possible 
  that 
  the 
  young 
  scale 
  may 
  be 
  conveyed 
  to 
  considerable 
  

   distances 
  by 
  flying 
  or 
  running 
  insects 
  or 
  by 
  birds; 
  ordinaril)', 
  how- 
  

   ever, 
  such 
  scattering 
  of 
  the 
  young 
  scale 
  will 
  have 
  no 
  permanent 
  

   effect, 
  since 
  females 
  distributed 
  here 
  and 
  there, 
  one 
  in 
  a 
  place, 
  would 
  

   be 
  little 
  likely 
  to 
  be 
  fertilized, 
  and 
  in 
  most 
  cases 
  would 
  perish 
  with- 
  

   out 
  reproduction. 
  I 
  have 
  lately 
  received, 
  however, 
  from 
  Professor 
  

   J. 
  M. 
  Stedman, 
  of 
  Missouri, 
  an 
  interesting 
  item 
  of 
  information 
  

   touching 
  upon 
  the 
  agency 
  of 
  birds 
  in 
  the 
  distribution 
  of 
  this 
  scale. 
  

   In 
  the 
  vicinity 
  of 
  infested 
  orchards 
  in 
  Missouri 
  Professor 
  Stedman 
  

   noticed 
  that 
  wherever 
  a 
  bird's 
  nest 
  was 
  seen 
  the 
  San 
  Jose 
  scale 
  had 
  

   commonly 
  established 
  itself, 
  sometimes, 
  indeed, 
  being 
  confined 
  to 
  

   the 
  branch 
  bearing 
  the 
  nest, 
  in 
  other 
  cases 
  having 
  distributed 
  itself 
  

   more 
  generally 
  over 
  the 
  tree. 
  Evidently 
  the 
  frequent 
  passage 
  of 
  

   birds 
  between 
  the 
  nest 
  and 
  the 
  infested 
  orchard 
  had 
  resulted 
  in 
  the 
  

   frequent 
  transfer 
  of 
  the 
  young, 
  probably 
  including 
  males 
  and 
  

   females 
  both, 
  and 
  in 
  the 
  establishment 
  of 
  colonies 
  in 
  condition 
  to 
  

   perpetuate 
  themselves 
  and 
  to 
  serve 
  as 
  further 
  centers 
  of 
  distribution. 
  

   On 
  the 
  other 
  hand, 
  its 
  extension 
  and 
  multiplication 
  are 
  sometimes 
  

   checked 
  by 
  natural 
  causes, 
  which 
  will 
  be 
  more 
  fully 
  discussed 
  under 
  

   another 
  head. 
  In 
  the 
  southern 
  part 
  of 
  its 
  range 
  in 
  California 
  — 
  that 
  

   is 
  from 
  San 
  Francisco 
  southward 
  — 
  it 
  has 
  more 
  or 
  less 
  completely 
  

   disappeared 
  from 
  regions 
  formerly 
  seriously 
  infested, 
  the 
  cause 
  of 
  

  

  * 
  Rep. 
  Ent., 
  N. 
  J. 
  Ag:r. 
  Coll. 
  Exper. 
  Station, 
  for 
  ISIW, 
  p. 
  546. 
  

  

  