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  larvae 
  feed 
  on 
  the 
  seedlings 
  of 
  winter 
  wheat, 
  and 
  hibernate 
  for 
  the 
  most 
  

   part 
  as 
  larvae, 
  though 
  possibly 
  some 
  may 
  reach 
  the 
  imago 
  stage 
  and 
  

   hibernate 
  as 
  such. 
  The 
  hibernated 
  larvae 
  begin 
  to 
  feed 
  again 
  in 
  

   spring, 
  and 
  it 
  is 
  then 
  that 
  the 
  damage 
  done 
  is 
  most 
  noticeable. 
  In 
  

   Denmark, 
  the 
  life-history 
  of 
  this 
  fly 
  is 
  somewhat 
  different. 
  In 
  that 
  

   country 
  there 
  appears 
  to 
  be 
  only 
  one 
  generation, 
  and 
  the 
  larvae 
  con- 
  

   tinue 
  feeding 
  into 
  the 
  month 
  of 
  May, 
  when 
  they 
  pupate. 
  The 
  flies 
  

   are 
  on 
  the 
  wing 
  in 
  July 
  and 
  August, 
  lay 
  their 
  eggs 
  in 
  the 
  earth 
  and 
  

   these 
  remain 
  until 
  the 
  spring. 
  It 
  would 
  appear 
  that 
  these 
  eggs 
  are 
  

   not 
  affected 
  by 
  flooding 
  of 
  the 
  fields. 
  Various 
  observations 
  tend 
  to 
  

   the 
  belief 
  that 
  the 
  attack 
  of 
  the 
  fly 
  is 
  influenced 
  by 
  the 
  treatment 
  of 
  

   the 
  soil, 
  and 
  especially 
  by 
  the 
  use 
  of 
  large 
  quantities 
  of 
  stable 
  manure. 
  

   It 
  has 
  been 
  observed 
  that 
  where 
  this 
  is 
  the 
  case, 
  the 
  attack 
  on 
  rye 
  

   and 
  wheat 
  in 
  autumn 
  is 
  frequently 
  severe, 
  and 
  further, 
  that 
  where 
  

   wheat 
  has 
  followed 
  potatoes 
  or 
  swedes, 
  the 
  attack 
  has 
  been 
  serious, 
  

   but 
  less 
  so 
  where 
  wheat 
  has 
  followed 
  rape, 
  mangels 
  or 
  beans. 
  Bonier 
  

   has 
  noticed 
  that 
  the 
  greatest 
  damage 
  is 
  done 
  by 
  the 
  fly 
  when 
  wheat 
  

   follows 
  clover 
  or 
  "timothy" 
  grass. 
  Rohrig 
  says 
  that 
  the 
  pest 
  is 
  

   serious 
  when 
  the 
  winter 
  ploughing 
  of 
  clover 
  has 
  not 
  been 
  carried 
  deep 
  

   enough 
  at 
  the 
  time 
  when 
  the 
  pupae 
  of 
  the 
  summer 
  brood 
  are 
  in 
  the 
  

   earth, 
  or 
  when 
  the 
  clover, 
  which 
  has 
  been 
  left 
  for 
  second 
  crop, 
  has 
  

   been 
  cut 
  and 
  the 
  ground 
  manured 
  and 
  ploughed 
  up 
  ; 
  he 
  thinks 
  that 
  

   if 
  the 
  ploughing 
  be 
  deep, 
  the 
  larvae 
  are 
  so 
  far 
  buried 
  that 
  the 
  imago 
  

   cannot 
  escape 
  from 
  the 
  earth, 
  and 
  also 
  that 
  rye 
  sown 
  on 
  a 
  two 
  to 
  

   three 
  year 
  clover 
  field, 
  does 
  not 
  suffer 
  from 
  the 
  fly 
  if 
  the 
  stubble 
  is 
  

   used 
  for 
  pasturing 
  sheep. 
  In 
  Denmark, 
  it 
  has 
  been 
  observed 
  that 
  the 
  

   pest 
  is 
  more 
  serious 
  when 
  the 
  soil 
  has 
  been 
  freshly 
  ploughed 
  in 
  June 
  

   and 
  July, 
  whereas 
  similar 
  treatment 
  in 
  September 
  has 
  the 
  reverse 
  

   effect. 
  This 
  system 
  of 
  ploughing 
  is 
  at 
  present 
  the 
  best 
  remedy. 
  

   It 
  is 
  also 
  advisable 
  to 
  sow 
  winter 
  varieties 
  in 
  those 
  places 
  where 
  the 
  

   attack 
  is 
  to 
  be 
  feared 
  and 
  in 
  the 
  case 
  of 
  rye, 
  to 
  sow 
  somewhat 
  more 
  

   thickly 
  than 
  usual, 
  so 
  that 
  in 
  event 
  of 
  attack, 
  a 
  reasonable 
  yield 
  may 
  

   be 
  obtained 
  ; 
  and 
  all 
  methods 
  w^hich 
  promote 
  the 
  rapid 
  and 
  healthy 
  

   growth 
  of 
  the 
  plants 
  are 
  useful. 
  Rohrig 
  is 
  further 
  of 
  opinion 
  that, 
  in 
  

   the 
  case 
  of 
  land 
  devoted 
  to 
  clover 
  where 
  only 
  one 
  cutting 
  is 
  intended, 
  

   only 
  pure 
  clover 
  with 
  no 
  admixture 
  of 
  grasses 
  should 
  be 
  sown, 
  but 
  

   in 
  those 
  cases 
  in 
  which 
  the 
  sowing 
  of 
  pure 
  clover 
  will 
  not 
  suffice, 
  or 
  

   where 
  it 
  is 
  intended 
  to 
  keep 
  the 
  clover 
  standing 
  for 
  two 
  seasons, 
  the 
  

   clover 
  stubble 
  should 
  be 
  deeply 
  ploughed 
  in 
  during 
  the 
  first 
  half 
  of 
  

   August, 
  as 
  by 
  this 
  means 
  the 
  larvae 
  attached 
  to 
  the 
  grass 
  are 
  buried 
  

   and 
  their 
  further 
  development 
  prevented. 
  It 
  is 
  also 
  advisable 
  about 
  

   the 
  end 
  of 
  August 
  to 
  sow 
  narrow 
  strips 
  of 
  rye 
  and 
  to 
  plough 
  these 
  in 
  

   deeply 
  after 
  a 
  fortnight 
  or 
  a 
  month, 
  and 
  then 
  to 
  proceed 
  with 
  the 
  

   sowing 
  of 
  the 
  winter 
  wheat. 
  This 
  plan 
  answers 
  well 
  in 
  Germany, 
  

   but 
  apparently 
  is 
  of 
  no 
  use 
  in 
  Denmark. 
  The 
  author 
  points 
  out 
  the 
  

   importance 
  of 
  full 
  and 
  detailed 
  studies 
  of 
  the 
  life-history 
  of 
  this 
  fly 
  

   in 
  the 
  particular 
  country 
  in 
  which 
  it 
  makes 
  its 
  appearance, 
  because 
  

   only 
  thus 
  can 
  an 
  effectual 
  means 
  of 
  attack 
  be 
  devised. 
  He 
  

   advises 
  agriculturists 
  in 
  threatened 
  districts 
  of 
  Austria 
  to 
  do 
  all 
  they 
  

   can 
  to 
  accelerate 
  the 
  growth 
  of 
  winter-wheat 
  so 
  as 
  to 
  make 
  it 
  resistant, 
  

   to 
  avoid 
  the 
  use 
  of 
  stable 
  manure 
  in 
  autumn 
  on 
  winter-wheat 
  fields 
  

   and 
  to 
  keep 
  them 
  through 
  the 
  summer 
  in 
  fallow, 
  delaying 
  cultivation 
  

   until 
  September. 
  

  

  