﻿39G 
  

  

  when 
  they 
  are 
  still 
  in 
  the 
  bud 
  and 
  cause 
  malformation 
  and 
  often 
  

   destruction 
  of 
  the 
  shoots, 
  and 
  sterility 
  in 
  the 
  flowers. 
  

  

  A 
  hymenopterous 
  parasite 
  of 
  F. 
  rohusta 
  has 
  been 
  found 
  at 
  Dercy, 
  

   but 
  not 
  at 
  Chesnoy. 
  This 
  species, 
  Thripoctenus 
  brui, 
  is 
  one 
  of 
  the 
  

   only 
  three 
  internal 
  parasites 
  of 
  thrips 
  that 
  are 
  known. 
  The 
  author 
  

   suggests 
  introducing 
  this 
  parasite 
  into 
  Chesnoy. 
  A 
  method 
  of 
  artificial 
  

   control 
  has 
  been 
  tried 
  in 
  England 
  by 
  Theobald 
  with 
  good 
  results 
  ; 
  it 
  

   consists 
  of 
  applying 
  a 
  soap 
  solution 
  containing 
  powdered 
  pyrethrum 
  

   in 
  suspension 
  to 
  the 
  affected 
  plants. 
  Sowing 
  the 
  same 
  crop 
  on 
  ground 
  

   that 
  has 
  borne 
  an 
  infested 
  crop 
  should 
  be 
  avoided, 
  and 
  if 
  possible 
  the 
  

   same 
  crop 
  should 
  not 
  even 
  be 
  sown 
  in 
  adjacent 
  fields. 
  Care 
  should 
  

   also 
  be 
  taken 
  that 
  the 
  ground 
  on 
  which 
  the 
  new 
  crop 
  is 
  to 
  be 
  sown 
  

   is 
  not 
  contaminated 
  w^th 
  thrips 
  by 
  the 
  use 
  of 
  supporting 
  sticks 
  from 
  

   infested 
  fields 
  ; 
  if 
  the 
  infestation 
  is 
  very 
  severe, 
  the 
  only 
  method 
  is 
  to 
  

   burn 
  the 
  entire 
  crop. 
  

  

  VuiLLET 
  (A.). 
  Les 
  Pucerons 
  du 
  Sorgho 
  au 
  Soudan 
  francais. 
  [The 
  

   millet 
  aphids 
  in 
  the 
  French 
  Sudan.] 
  — 
  -Revue 
  Scientifiqiie, 
  Paris, 
  

   2nd 
  May 
  1914, 
  pp. 
  563-564. 
  

  

  The 
  cultivation 
  of 
  millet 
  {Sorghum 
  vulgare) 
  is 
  of 
  considerable 
  

   economic 
  importance 
  in 
  the 
  French 
  Sudan, 
  a 
  failure 
  in 
  the 
  crop 
  being 
  

   nothing 
  short 
  of 
  a 
  calamity 
  for 
  the 
  inhabitants. 
  Failure 
  may 
  be 
  due 
  

   either 
  to 
  too 
  dry 
  weather, 
  or 
  more 
  commonly 
  to 
  the 
  attack 
  of 
  Aphis 
  

   sorghi, 
  Theo. 
  This 
  insect 
  not 
  only 
  sucks 
  the 
  juices 
  of 
  the 
  millet, 
  but 
  

   secretes 
  a 
  sticky 
  substance 
  that 
  serves 
  as 
  a 
  substratum 
  for 
  the 
  growth 
  

   of 
  certain 
  fungi, 
  which 
  by 
  covering 
  the 
  leaves, 
  stops 
  the 
  respiration 
  

   and 
  assimilation 
  of 
  the 
  plant. 
  The 
  species 
  can 
  maintain 
  itself 
  in 
  an 
  

   active 
  state 
  throughout 
  the 
  year. 
  

  

  Fortunately, 
  Aphis 
  sorghi 
  is 
  subject 
  to 
  the 
  attack 
  of 
  numerous 
  

   natural 
  enemies. 
  Among 
  these 
  are 
  the 
  Coccinellids, 
  Chilomenes 
  vicina, 
  

   Muls., 
  Exochomus 
  flavipes 
  v. 
  troberti, 
  Muls., 
  and 
  Scymnus 
  plebejus, 
  

   AVeise, 
  the 
  larvae 
  and 
  adults 
  of 
  which 
  prey 
  on 
  A. 
  sorghi 
  ; 
  the 
  larvae 
  

   of 
  the 
  Syrphids, 
  Paragus 
  longiventris, 
  Loew, 
  P. 
  serratus, 
  F., 
  P. 
  

   borbonicus, 
  Macq., 
  Xanthogramma 
  aegyptium, 
  Wied,, 
  and 
  Leucopis 
  

   sp. 
  ; 
  and 
  Chrysopa 
  ouilleti,: 
  Nav., 
  C. 
  incongrua, 
  Nav. 
  and 
  C. 
  

   oralis, 
  Nav. 
  

  

  Millet 
  is 
  attacked 
  in 
  the 
  French 
  Soudan 
  by 
  yet 
  another 
  species 
  of 
  

   Aphis, 
  namely 
  A. 
  maidis, 
  w^hich 
  is 
  widely 
  distributed 
  in 
  the 
  United 
  

   States, 
  Australia 
  and 
  Japan. 
  This 
  species, 
  which 
  is 
  called 
  the 
  green 
  

   Aphis 
  to 
  distinguish 
  it 
  from 
  A. 
  sorghi 
  w^hich 
  is 
  know^n 
  as 
  the 
  white 
  

   Aphis, 
  is 
  formd 
  on 
  the 
  ends 
  of 
  the 
  leaves 
  of 
  millet 
  and 
  maize, 
  and 
  on 
  

   the 
  male 
  inflorescences 
  of 
  the 
  latter. 
  It 
  is 
  much 
  less 
  harmful 
  than 
  

   A. 
  sorghi. 
  

  

  The 
  chief 
  method 
  of 
  controlling 
  these 
  insects 
  is 
  to 
  dig 
  up 
  and 
  burn 
  

   all 
  the 
  infested 
  plants 
  before 
  the 
  beginning 
  of 
  February 
  : 
  this 
  is 
  now 
  

   compulsory 
  by 
  law. 
  To 
  encourage 
  the 
  natural 
  enemies 
  of 
  the 
  Aphids, 
  

   a 
  few 
  plants 
  of 
  Leptadenia 
  lancifera 
  should 
  be 
  allowed 
  to 
  grow^ 
  at 
  

   intervals 
  in 
  the 
  millet 
  crops, 
  as 
  this 
  plant 
  is 
  frequented 
  by 
  most 
  of 
  the 
  

   Coleoptera 
  and 
  Diptera 
  which 
  are 
  predaceous 
  on 
  the 
  Aphids. 
  

  

  