﻿231 
  

  

  (2) 
  petroleiun-soap, 
  if 
  well 
  emulsified 
  ; 
  (3) 
  Cooper's 
  Fluid, 
  at 
  a 
  strength 
  

   of 
  1 
  to 
  1 
  J 
  parts 
  in 
  100 
  parts 
  of 
  water. 
  Treatment 
  must 
  be 
  effected 
  at 
  

   the 
  following 
  times 
  : 
  — 
  One 
  application 
  after 
  fruit-picking, 
  when 
  the 
  

   young 
  scales 
  are 
  not 
  yet 
  protected 
  by 
  the 
  fourth 
  envelope 
  of 
  their 
  

   shield 
  ; 
  a 
  second 
  application 
  in 
  spring, 
  when 
  vegetation 
  starts 
  ; 
  and 
  

   two 
  others 
  during 
  summer, 
  the 
  last 
  being 
  not 
  later 
  than 
  the 
  middle 
  of 
  

   September. 
  If 
  infection 
  is 
  slight, 
  the 
  leaves 
  may 
  be 
  caused 
  to 
  fall 
  

   (the 
  orange 
  scale 
  only 
  fastens 
  on 
  the 
  leaves) 
  by 
  spraying 
  with 
  the 
  fol- 
  

   lowing, 
  after 
  fruit 
  picking 
  : 
  — 
  Potassium 
  carbonate 
  2 
  parts 
  by 
  weight, 
  

   common 
  salt 
  3 
  parts 
  and 
  water 
  100 
  parts. 
  It 
  is 
  absolutely 
  necessary 
  

   that 
  all 
  cultivators 
  should 
  act 
  in 
  unison. 
  

  

  CoMTE 
  ( 
  — 
  ). 
  Les 
  parasites 
  du 
  bI6. 
  [Parasites 
  of 
  wheat.] 
  — 
  Rev. 
  Agric. 
  

   Vitic. 
  Afr. 
  Nord, 
  Algiers; 
  iii, 
  no. 
  96, 
  97; 
  10th-17th 
  Jan. 
  1914; 
  

   pp. 
  31-33, 
  54-60; 
  14 
  figs. 
  

  

  Hylemyia 
  coarctata, 
  the 
  wheat 
  fly, 
  which 
  closely 
  resembles 
  Musca 
  

   domestica, 
  has 
  injured 
  wheat 
  in 
  Tunisia, 
  where 
  the 
  author 
  observed 
  

   it 
  in 
  1911 
  near 
  Beja, 
  Tunis, 
  and 
  Kairouan. 
  Two 
  generations 
  occur 
  

   annually. 
  The 
  larvae 
  of 
  the 
  first 
  gnaw 
  the 
  inside 
  of 
  the 
  stem, 
  causing 
  

   the 
  plant 
  to 
  turn 
  yellow, 
  but 
  rarely 
  killing 
  it. 
  They 
  are 
  always 
  found 
  

   at 
  a 
  depth 
  of 
  1 
  to 
  3 
  centimetres 
  underground. 
  Pupation 
  takes 
  place 
  

   in 
  the 
  stem 
  during 
  January 
  and 
  the 
  imagines 
  appear 
  from 
  February 
  

   to 
  March. 
  The 
  larvae 
  of 
  the 
  second 
  generation 
  burrow 
  in 
  the 
  secon- 
  

   dary 
  stems 
  due 
  to 
  tillering 
  ; 
  on 
  reaching 
  full 
  development 
  they 
  leave 
  

   the 
  plant 
  and 
  pupate 
  in 
  the 
  soil. 
  The 
  larvae 
  are 
  never 
  found 
  in 
  the 
  

   principal 
  stems, 
  which 
  remain 
  vigorous. 
  Thus 
  the 
  past 
  season, 
  

   which 
  was 
  exceptionally 
  dry, 
  has 
  largely 
  favoured 
  their 
  increase, 
  

   and 
  tillering 
  being 
  also 
  checked 
  by 
  the 
  lack 
  of 
  moisture, 
  the 
  damage 
  

   done 
  was 
  noticeable, 
  whereas 
  this 
  is 
  not 
  the 
  case 
  in 
  a 
  moist 
  season. 
  

   The 
  author 
  has 
  never 
  observed 
  this 
  pest 
  except 
  on 
  various 
  kinds 
  of 
  

   wheat, 
  though 
  it 
  has 
  been 
  stated 
  that 
  it 
  injures 
  barley 
  and 
  rye. 
  The 
  

   only 
  advisable 
  means 
  of 
  combat 
  are 
  to 
  obtain 
  by 
  proper 
  cultural 
  

   methods, 
  the 
  use 
  of 
  manures, 
  and 
  the 
  selection 
  of 
  vigorous 
  seed 
  suited 
  

   to 
  the 
  soil, 
  such 
  robust 
  plants 
  as 
  are 
  able 
  to 
  withstand 
  the 
  injury 
  and 
  

   produce 
  remunerative 
  crops. 
  The 
  attack 
  of 
  the 
  first 
  generation 
  is 
  

   the 
  most 
  dangerous, 
  and 
  may 
  be 
  avoided 
  to 
  a 
  certain 
  degree 
  by 
  late 
  

   sowing. 
  

  

  Sitotroga 
  cerealella, 
  is 
  prevalent 
  in 
  French 
  North 
  Africa. 
  The 
  

   moths 
  appear 
  in 
  May, 
  and 
  soon 
  afterwards 
  the 
  females 
  lay 
  their 
  eggs 
  on 
  

   the 
  milky 
  grains 
  of 
  wheat, 
  barley 
  and 
  oats, 
  wheat 
  being 
  preferred. 
  

   About 
  50 
  to 
  80 
  eggs 
  are 
  laid. 
  The 
  young 
  larvae 
  penetrate 
  into 
  the 
  

   grain, 
  upon 
  which 
  they 
  feed, 
  and 
  at 
  harvesting 
  and 
  threshing 
  time 
  

   they 
  are 
  carried 
  into 
  the 
  barns. 
  In 
  the 
  early 
  days 
  of 
  July 
  the 
  moths 
  

   of 
  the 
  second 
  generation 
  appear 
  and 
  proceed 
  to 
  attack 
  the 
  wheat 
  

   stored 
  in 
  the 
  granaries, 
  where 
  a 
  third 
  and 
  even 
  fourth 
  generation 
  may 
  

   be 
  produced. 
  

  

  Mayetiola 
  (Cecidomyia) 
  destructor, 
  Say, 
  the 
  Hessian 
  fly, 
  has 
  caused 
  

   serious 
  damage 
  to 
  barley 
  in 
  Tunisia. 
  In 
  the 
  author's 
  experiments 
  

   the 
  hfe-cycle 
  of 
  the 
  first 
  generation 
  took 
  six 
  weeks 
  — 
  from 
  the 
  10th 
  

   February 
  to 
  the 
  21st 
  March 
  ; 
  the 
  second 
  generation 
  five 
  weeks. 
  In 
  

   comparatively 
  hot 
  countries 
  like 
  Tunisia 
  development 
  is 
  arrested 
  

   during 
  the 
  months 
  of 
  July, 
  August, 
  and 
  September. 
  On 
  Tunisian 
  

  

  