﻿204 
  History 
  of 
  Durham. 
  

  

  so 
  remarkably 
  developed 
  in 
  the 
  perfect 
  moth. 
  Onlj' 
  under 
  

   peculiar 
  circumstances 
  are 
  these 
  pupae 
  found 
  at 
  a 
  greater 
  

   depth 
  than 
  may 
  be 
  reached 
  by 
  deep 
  plowing. 
  A 
  further 
  

   means 
  of 
  reducing 
  the 
  number 
  of 
  these 
  insects 
  is 
  therefore 
  

   by 
  fall 
  or 
  winter 
  plowing 
  the 
  tobacco 
  fields. 
  It 
  must 
  be 
  

   said, 
  however, 
  that 
  even 
  if 
  every 
  egg, 
  worm, 
  moth, 
  and 
  

   chrysalid 
  in 
  a 
  given 
  neighborhood 
  were 
  destroyed, 
  high 
  

   winds, 
  or 
  even 
  the 
  lighter 
  breezes 
  of 
  the 
  summer 
  evenings, 
  

   bring 
  other 
  moths 
  many 
  miles. 
  The 
  tobacco 
  grower 
  should 
  

   instruct 
  those 
  in 
  his 
  employ 
  not 
  to 
  destroy 
  any 
  horn-worm 
  

   found 
  with 
  the 
  cocoons 
  of 
  the 
  parasite 
  Microgaster 
  congre- 
  

   gata 
  attached 
  to 
  its 
  body. 
  These 
  cocoons 
  are 
  white, 
  of 
  a 
  

   regular 
  oval 
  form, 
  a 
  little 
  more 
  than 
  an 
  eighth 
  of 
  an 
  inch 
  

   long 
  and 
  about 
  one-sixteenth 
  of 
  an 
  inch 
  broad, 
  and 
  resem- 
  

   bles 
  small 
  grains 
  of 
  rice. 
  From 
  ten 
  to 
  a 
  hundred 
  of 
  these 
  

   cocoons 
  are 
  found 
  upon 
  a 
  single 
  horn-worm. 
  The 
  worm 
  so 
  

   infested 
  may 
  be 
  removed 
  from 
  the 
  tobacco 
  plant, 
  but 
  should 
  

   be 
  handled 
  carefully 
  and 
  placed 
  where 
  the 
  cocoons 
  may 
  not 
  

   be 
  injured, 
  so 
  that 
  the 
  parasites 
  may 
  hatch 
  undisturbed. 
  

   The 
  flies 
  which 
  issue 
  from 
  the 
  cocoons 
  are 
  black, 
  with 
  clear, 
  

   transparent 
  wings 
  and 
  legs 
  of 
  a 
  bright 
  tawny 
  color, 
  the 
  hue 
  

   of 
  beeswax, 
  with 
  the 
  hind 
  feet 
  and 
  the 
  tips 
  of 
  the 
  hind 
  

   shanks 
  dusky. 
  

  

  The 
  testimony 
  of 
  all 
  tobacco 
  growers 
  points 
  to 
  the 
  one 
  

   conclusion 
  about 
  insect 
  enemies. 
  No 
  methods 
  of 
  preven- 
  

   tion 
  or 
  destruction 
  can 
  justify 
  a 
  single's 
  day's 
  neglect 
  to 
  

   search 
  for 
  and 
  destroy 
  cut-worms 
  about 
  newly-set 
  plants 
  

   and 
  the 
  eggs 
  and 
  larva? 
  of 
  the 
  sphinx 
  moth 
  upon 
  the 
  ex- 
  

   panded 
  leaves 
  throughout 
  the 
  season. 
  

  

  DISEASES 
  OF 
  THE 
  TOBACCO 
  PLANT. 
  

  

  The 
  tobacco 
  plant 
  is 
  subject 
  to 
  certain 
  diseases, 
  few 
  in 
  

   number, 
  however, 
  and 
  rarely 
  resulting 
  in 
  very 
  serious 
  dam- 
  

   age. 
  Unfavorable 
  seasons, 
  too 
  wet 
  or 
  too 
  dry, 
  often 
  reduce 
  

   the 
  yield 
  and 
  impair 
  the 
  value 
  of 
  the 
  product; 
  but 
  dis- 
  

   eases, 
  properly 
  so 
  called, 
  seldom 
  affect 
  more 
  than 
  a 
  few 
  

   plants, 
  or 
  perhaps 
  a 
  smaller 
  portion 
  of 
  a 
  field. 
  Reports 
  

   from 
  widely 
  separated 
  districts 
  mention 
  the 
  same 
  diseases, 
  

   all 
  of 
  which 
  result 
  from 
  deficiencies 
  in 
  the 
  soil 
  or 
  its 
  prep- 
  

   aration, 
  or 
  from 
  peculiarities 
  of 
  the 
  seasons 
  during 
  growth. 
  

  

  A 
  disease 
  known 
  in 
  New 
  England 
  as 
  " 
  brown 
  rust," 
  and 
  

   in 
  the 
  South 
  as 
  "firing" 
  and 
  "field-fire," 
  prevails 
  to 
  some 
  ex- 
  

   tent 
  every 
  year. 
  It 
  appears 
  in 
  very 
  wet 
  or 
  very 
  dry 
  weather, 
  

  

  