﻿42 
  

  

  from 
  what 
  is 
  known 
  as 
  the 
  western 
  advance 
  line 
  of 
  the 
  disease. 
  

  

  Our 
  pathologists 
  have 
  reported 
  some 
  very 
  interesting 
  facts 
  

   in 
  regard 
  to 
  the 
  dissemination 
  of 
  the 
  blight. 
  In 
  the 
  prelimin- 
  

   ary 
  report 
  of 
  the 
  summer's 
  work 
  -at 
  our 
  field 
  laboratories 
  the^ 
  

   results 
  tend 
  to 
  show: 
  

  

  First, 
  the 
  prolific 
  ascospore 
  stage 
  is 
  very 
  important 
  in 
  caus- 
  

   ing 
  the 
  spread 
  of 
  the 
  blight, 
  the 
  spores 
  at 
  this 
  stage 
  being 
  forci- 
  

   bly 
  ejected 
  from 
  the 
  pustules 
  and 
  borne 
  through 
  the 
  air 
  for 
  

   some 
  distance. 
  This 
  ejection 
  of 
  spores 
  takes 
  place 
  under 
  natural 
  

   field 
  conditions 
  only 
  when 
  the 
  bark 
  has 
  been 
  soaked 
  by 
  rain, 
  

   but 
  the 
  expulsion 
  of 
  spores 
  is 
  also 
  dependent 
  upon 
  temperature 
  

   conditions 
  and 
  ceases 
  entirely 
  at 
  temperatures 
  from 
  42 
  to 
  46 
  

   degrees 
  F. 
  and 
  below. 
  

  

  Second, 
  the 
  wind 
  plays 
  a 
  large 
  part 
  in 
  local 
  ascospore 
  dis- 
  

   semination. 
  

  

  Third, 
  birds 
  and 
  insects 
  (except 
  ants) 
  are 
  apparently 
  of 
  very 
  

   little 
  importance 
  in 
  the 
  dissemination 
  of 
  the 
  blight 
  except 
  in 
  

   providing 
  wounds. 
  Further 
  investigations 
  of 
  the 
  importance 
  

   of 
  ants 
  is 
  being 
  made 
  during 
  the 
  present 
  winter. 
  

  

  Several 
  kinds 
  of 
  beetles 
  have 
  been 
  observed 
  eating 
  the 
  pus- 
  

   tules 
  and 
  are 
  in 
  this 
  way 
  beneficial, 
  since 
  tests 
  show 
  that 
  they 
  

   digest 
  and 
  destroy 
  the 
  spores. 
  It 
  has 
  also 
  been 
  suggested 
  by 
  

   workers 
  in 
  the 
  Bureau 
  of 
  Entomology 
  that 
  such 
  beetles, 
  which 
  

   are 
  of 
  several 
  kinds, 
  may 
  be 
  of 
  value 
  in 
  the 
  attempt 
  to 
  control 
  

   the 
  disease. 
  These 
  are 
  perhaps 
  the 
  only 
  natural 
  enemies 
  dis- 
  

   covered 
  to 
  date. 
  

  

  The 
  proper 
  classification 
  of 
  the 
  chestnut 
  blight 
  fungus 
  has 
  

   also 
  been 
  the 
  subject 
  of 
  much 
  discussion. 
  Last 
  winter 
  specimens 
  

   of 
  what 
  in 
  external 
  characteristics 
  appeared 
  to 
  be 
  Diaporthe 
  

   parasitica 
  were 
  found 
  in 
  western 
  Pennsylvania, 
  Virginia 
  and 
  

   elsewhere, 
  growing 
  upon 
  chestnut, 
  oak 
  and 
  other 
  species. 
  This 
  

   condition 
  was 
  puzzling 
  and 
  the 
  subject 
  of 
  some 
  controversy. 
  

   It 
  has 
  been 
  found, 
  however, 
  that 
  this 
  fungus, 
  called 
  the 
  "Con- 
  

   nellsville 
  fungus," 
  is 
  a 
  distinct 
  species 
  closely 
  related 
  to 
  the 
  

   true 
  blight 
  fungus, 
  being, 
  however, 
  entirely 
  saprophytic. 
  Cul- 
  

   tural 
  distinctions 
  are 
  apparent 
  and 
  the 
  ascospores 
  differ 
  in 
  size 
  

   and 
  shape 
  so 
  that 
  no 
  further 
  confusion 
  need 
  occur. 
  

  

  Upon 
  the 
  question 
  of 
  immunity 
  of 
  certain 
  kinds 
  of 
  Asiatic 
  

   stock, 
  there 
  is 
  very 
  little 
  to 
  report 
  beyond 
  what 
  was 
  known 
  

   one 
  year 
  ago. 
  In 
  the 
  investigations 
  made 
  the 
  work 
  has 
  been 
  

   hampered 
  by 
  the 
  fact 
  that 
  much 
  of 
  the 
  so-called 
  Japanese 
  stock 
  

   is 
  in 
  reality 
  a 
  hybrid 
  of 
  European 
  or 
  American 
  species. 
  In 
  

  

  