﻿208 
  CONTAGIOUS 
  DISEASES 
  OF 
  THE 
  CHINCH-BUG. 
  

  

  Champaign, 
  a 
  large 
  beetle 
  (Parandra 
  brunnea) 
  found 
  dead 
  under 
  a 
  log 
  being 
  

   thickly 
  covered 
  with 
  a 
  profuse 
  growth 
  of 
  this 
  same 
  Botrytis. 
  . 
  . 
  . 
  

  

  At 
  present 
  it 
  appears 
  that 
  all, 
  except 
  perhaps 
  the 
  bacterial 
  disease, 
  are 
  closely 
  

   dependent 
  for 
  their 
  activity 
  on 
  the 
  weather, 
  although 
  their 
  generally 
  rapid 
  develop- 
  

   ment 
  over 
  so 
  large 
  a 
  territory 
  indicates 
  their 
  presence 
  at 
  all 
  times 
  to 
  a 
  greater 
  or 
  

   less 
  extent. 
  That 
  the 
  bacterial 
  disease 
  is 
  less 
  dependent 
  upon 
  wet 
  weather 
  for 
  its 
  

   activity, 
  was 
  shown 
  by 
  occurrences 
  detailed 
  in 
  my 
  entomological 
  report 
  for 
  1882, 
  

   borne 
  out 
  as 
  these 
  are 
  by 
  our 
  office 
  experiments 
  this 
  year. 
  While 
  in 
  order 
  to 
  obtain 
  

   the 
  free 
  and 
  rapid 
  development 
  of 
  the 
  Entomophthora 
  or 
  Botrytis 
  it 
  was 
  necessary 
  

   to 
  enclose 
  the 
  chinch-bugs 
  under 
  glass 
  over 
  moist 
  earth, 
  the 
  bacterial 
  disease 
  ap- 
  

   peared 
  or 
  continued 
  equally 
  well 
  in 
  specimens 
  kept 
  perfectly 
  dry, 
  and 
  even 
  where 
  

   they 
  were 
  evidently 
  perishing 
  from 
  simple 
  drouth. 
  However, 
  the 
  appearance 
  of 
  

   even 
  this 
  disease 
  only 
  after 
  a 
  season 
  of 
  considerable 
  rain, 
  and 
  our 
  failure 
  to 
  detect 
  

   it 
  in 
  the 
  field 
  in 
  extremely 
  dry 
  weather, 
  make 
  it 
  probable 
  that 
  this 
  also 
  remains 
  in 
  

   abeyance 
  under 
  conditions 
  recognized 
  as 
  especially 
  favorable 
  to 
  chinch-bug 
  in- 
  

   crease. 
  

  

  That 
  it 
  is 
  chiefly 
  to 
  the 
  joint 
  action 
  of 
  these 
  various 
  disease-producing 
  fungi, 
  

   favored 
  as 
  they 
  are 
  by 
  moist 
  weather, 
  that 
  we 
  owe 
  the 
  disappearance 
  of 
  chinch-bug 
  

   outbreaks, 
  is 
  rendered 
  almost 
  certain 
  by 
  the 
  facts 
  now 
  on 
  record. 
  

  

  In 
  the 
  November, 
  1890, 
  issue 
  of 
  Insect 
  Life, 
  (Vol. 
  hi, 
  No. 
  4, 
  p. 
  141,) 
  is 
  

   printed 
  a 
  paper 
  " 
  On 
  the 
  Use 
  of 
  Contagious 
  Diseases 
  in 
  Contending 
  with 
  In- 
  

   jurious 
  Insects," 
  by 
  Prof. 
  Herbert 
  Osborn. 
  The 
  paper 
  was 
  read 
  before 
  the 
  

   Entomological 
  Club 
  of 
  the 
  American 
  Association 
  for 
  the 
  Advancement 
  of 
  

   Science, 
  at 
  Indianapolis, 
  August 
  22, 
  1890. 
  This 
  interesting 
  paper 
  closes 
  with 
  

   the 
  statement 
  that 
  the 
  author 
  believes 
  we 
  are 
  justified 
  in 
  the 
  following 
  infer- 
  

   ences 
  : 
  

  

  First. 
  That 
  there 
  are 
  diseases 
  amply 
  sufficient 
  as 
  a 
  basis 
  for 
  economic 
  work, 
  the 
  

   bacterial 
  forms 
  giving 
  the 
  most 
  promise 
  for 
  all 
  cases 
  where 
  early 
  results 
  are 
  desired, 
  

   while 
  those 
  due 
  to 
  fungi, 
  so 
  far 
  as 
  present 
  knowledge 
  goes, 
  propagating 
  slowly, 
  can 
  

   only 
  be 
  used 
  as 
  slow 
  but 
  efficient 
  checks 
  to 
  injurious 
  forms, 
  the 
  most 
  we 
  can 
  do 
  with 
  

   them 
  being 
  to 
  introduce 
  them 
  in 
  localities 
  where 
  not 
  already 
  found. 
  

  

  Second. 
  That 
  the 
  diseases 
  can 
  be 
  controlled 
  to 
  the 
  extent 
  of 
  preserving 
  the 
  germs 
  

   for 
  a 
  season 
  and 
  transporting 
  them 
  from 
  place 
  to 
  place, 
  to 
  use 
  for 
  inoculation; 
  but 
  

   that 
  its 
  spread 
  in 
  nature 
  will 
  be 
  affected 
  by 
  conditions 
  beyond 
  our 
  control, 
  while 
  only 
  

   such 
  insects 
  as 
  occur 
  gregariously, 
  or 
  live 
  in 
  mingled 
  hosts, 
  can 
  be 
  attacked 
  to 
  ad- 
  

   vantage. 
  

  

  Third. 
  That 
  the 
  cost 
  of 
  application 
  would 
  prevent 
  its 
  adoption 
  except 
  in 
  certain 
  

   forms. 
  

  

  Finally, 
  we 
  must 
  consider 
  this 
  method 
  of 
  contending 
  with 
  insects 
  at 
  best 
  as 
  but 
  

   one 
  of 
  a 
  number 
  of 
  profitable 
  methods, 
  to 
  be 
  used 
  in 
  certain 
  cases, 
  where 
  other 
  

   methods 
  are 
  insufficient, 
  and 
  to 
  supplement 
  other 
  methods 
  where 
  it 
  can 
  be 
  done 
  to 
  

   advantage. 
  With 
  this 
  end 
  in 
  view, 
  the 
  diseases 
  of 
  insects 
  are 
  worthy 
  of 
  the 
  most 
  

   careful 
  study, 
  and 
  will 
  not, 
  I 
  think, 
  disappoint 
  us 
  in 
  their 
  final 
  results. 
  

  

  In 
  the 
  Manhattan 
  Nationalist 
  of 
  February 
  12, 
  1891, 
  appeared 
  an 
  article 
  

   by 
  Prof. 
  E. 
  A. 
  Popenoe, 
  entitled 
  "The 
  Chinch-Bug 
  Disease 
  Again." 
  In 
  this 
  

   article 
  Professor 
  Popenoe 
  refers 
  to 
  various 
  phases 
  of 
  my 
  experiments, 
  and 
  

   closes 
  by 
  saying: 
  

  

  The 
  inferences 
  from 
  all 
  the 
  observations 
  here 
  quoted 
  is, 
  that 
  unless 
  the 
  climatic 
  

   conditions 
  are 
  favorable 
  to 
  the 
  growth 
  of 
  the 
  Empusa 
  parasite, 
  the 
  bugs 
  will 
  thrive 
  

  

  