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  THE 
  DISPERSION 
  OF 
  THE 
  GIPSY 
  MOTH. 
  

  

  EFFECT 
  OF 
  WIND 
  SPREAD 
  ON 
  THE 
  PROBLEM 
  OF 
  GIPSY-MOTH 
  

  

  CONTROL. 
  

  

  The 
  fact 
  that 
  gipsy-moth 
  caterpillars 
  are 
  spread 
  chiefly 
  by 
  wind 
  

   during 
  the 
  time 
  they 
  are 
  in 
  the 
  first 
  stage 
  and 
  that 
  for 
  this 
  reason 
  

   the 
  present 
  spread 
  of 
  the 
  insect 
  is 
  toward 
  the 
  northeast, 
  northwest, 
  

   and 
  north 
  has 
  been 
  sufficiently 
  demonstrated. 
  Another 
  factor 
  which 
  

   enters 
  into 
  the 
  problem 
  to 
  a 
  greater 
  or 
  less 
  extent, 
  and 
  which 
  has 
  an 
  

   important 
  bearing 
  on 
  the 
  spread 
  of 
  young 
  caterpillars 
  by 
  air 
  cur- 
  

   rents, 
  is 
  the 
  altitude 
  of 
  the 
  woodland 
  in 
  the 
  various 
  towns. 
  

  

  Whether 
  high 
  altitudes 
  are 
  more 
  likely 
  to 
  become 
  infested 
  in 
  this 
  

   way 
  than 
  low 
  areas 
  it 
  is 
  difficult 
  to 
  state, 
  but 
  there 
  can 
  be 
  no 
  question 
  

   in 
  regard 
  to 
  the 
  difference 
  in 
  temperature 
  of 
  winds 
  after 
  having 
  

   passed 
  over 
  an 
  area 
  of 
  high 
  land. 
  For 
  example, 
  the 
  cold 
  winds 
  which 
  

   sweep 
  down 
  the 
  New 
  England 
  coast 
  from 
  the 
  northeast 
  and 
  east 
  are 
  

   not 
  accompanied 
  by 
  as 
  low 
  temperature, 
  nor 
  are 
  such 
  winds 
  as 
  cold 
  

   or 
  penetrating 
  in 
  the 
  central 
  part 
  of 
  Massachusetts* 
  as 
  they 
  are 
  along 
  

   the 
  seacoast. 
  As 
  high 
  winds 
  must 
  be 
  accompanied 
  by 
  high 
  tempera- 
  

   ture 
  in 
  order 
  to 
  bring 
  about 
  the 
  spread 
  of 
  young 
  caterpillars, 
  it 
  can 
  

   be 
  stated 
  that 
  after 
  the 
  territory 
  on 
  the 
  west 
  side 
  of 
  the 
  watershed 
  in 
  

   Massachusetts 
  and 
  New 
  Hampshire 
  becomes 
  infested 
  to 
  such 
  a 
  degree 
  

   that 
  large 
  areas 
  are 
  defoliated, 
  the 
  spread 
  of 
  the 
  young 
  caterpillars 
  

   by 
  wind 
  will 
  be 
  more 
  far-reaching 
  and 
  more 
  rapid 
  than 
  it 
  has 
  been 
  

   at 
  any 
  period 
  since 
  the 
  moth 
  first 
  became 
  established. 
  It 
  is 
  indeed 
  

   a 
  fortunate 
  thing 
  that 
  the 
  gipsy 
  moth 
  first 
  found 
  lodgment 
  on 
  the 
  

   North 
  Atlantic 
  seaboard, 
  on 
  account 
  of 
  the 
  various 
  elements 
  which 
  

   have 
  worked 
  together 
  to 
  restrict 
  its 
  spread. 
  If 
  the 
  insect 
  had 
  first 
  

   escaped 
  in 
  central 
  Massachusetts, 
  in 
  Connecticut, 
  or 
  in 
  New 
  York 
  

   State 
  there 
  would 
  have 
  been 
  ample 
  opportunity 
  for 
  spread 
  in 
  all 
  

   directions, 
  and 
  it 
  would 
  have 
  been 
  difficult 
  to 
  restrict 
  it 
  to 
  anything 
  

   like 
  the 
  area 
  which 
  it 
  now 
  occupies. 
  

  

  SUMMARY. 
  

  

  The 
  gipsy 
  moth 
  is 
  spread 
  by 
  local 
  and 
  long-distance 
  means. 
  

  

  Local 
  spread 
  may 
  be 
  due 
  to 
  the 
  transportation 
  of 
  caterpillars 
  or 
  

   egg 
  clusters 
  on 
  carriages 
  or 
  wagons 
  that 
  move 
  for 
  only 
  a 
  short 
  dis- 
  

   tance 
  outside 
  the 
  infested 
  territory. 
  The 
  egg 
  clusters 
  may 
  be 
  carried 
  

   on 
  driftwood 
  which 
  floats 
  down 
  rivers 
  during 
  the 
  spring. 
  

  

  Long-distance 
  spread 
  may 
  be 
  due 
  to 
  the 
  shipment 
  of 
  egg 
  clusters 
  on 
  

   lumber 
  products, 
  nursery 
  stock, 
  or 
  boxes 
  from 
  the 
  infested 
  territory 
  

   to 
  any 
  points 
  where 
  such 
  goods 
  are 
  unloaded. 
  Caterpillars 
  may 
  be, 
  

   and 
  often 
  are, 
  carried 
  long 
  distances 
  on 
  automobiles 
  or 
  trolley 
  cars, 
  

   and 
  cases 
  are 
  on 
  record 
  where 
  colonies 
  have 
  been 
  established 
  in 
  

   this 
  way. 
  

  

  