﻿INSECTS 
  INJURIOUS 
  TO 
  CROPS 
  IN 
  ZANZIBAR. 
  149 
  

  

  Pseudococcus 
  obtusus, 
  Newst. 
  At 
  times 
  this 
  is 
  a 
  serious 
  pest. 
  It 
  is 
  one 
  of 
  the 
  

   commonest 
  Coccids 
  of 
  the 
  island 
  and 
  feeds 
  on 
  a 
  variety 
  of 
  hosts. 
  Many 
  experimental 
  

   plants 
  of 
  cotton 
  were 
  completely 
  covered, 
  the 
  main 
  stem 
  being 
  smothered. 
  

  

  Pseudococcus 
  virgatus, 
  Ckll. 
  Found 
  occasionally 
  on 
  leaves 
  and 
  beneath 
  the 
  

   sepals. 
  This 
  Coccid 
  is 
  very 
  abundant 
  on 
  a 
  number 
  of 
  ornamental 
  plants 
  and 
  shrubs. 
  

  

  Pseudococcus 
  citri, 
  Risso. 
  A 
  rare 
  species 
  on 
  cotton. 
  

  

  INSECTS 
  AFFECTING 
  CEREALS. 
  

  

  The 
  principal 
  cereals 
  cultivated 
  are 
  rice, 
  maize, 
  and 
  millet 
  (Sorghum 
  vulgare),. 
  

   none 
  of 
  them 
  in 
  any 
  great 
  quantity. 
  

  

  Lepidoptera. 
  

  

  Cirphis 
  loreyi, 
  Dup. 
  The 
  larvae 
  of 
  this 
  Noctuid 
  are 
  common 
  in 
  all 
  maize 
  

   fields. 
  They 
  bore 
  and 
  tunnel 
  through 
  the 
  main 
  stalk, 
  attack 
  the 
  base 
  of 
  the 
  cob, 
  

   and 
  occasionally 
  feed 
  on 
  unripe 
  seeds. 
  Pupation 
  takes 
  place 
  either 
  in 
  the 
  stalk 
  

   or 
  in 
  the 
  cob. 
  The 
  moist 
  white 
  excrement, 
  very 
  typical 
  of 
  the 
  presence 
  of 
  the 
  larva, 
  

   is 
  generally 
  found 
  at 
  the 
  base 
  of 
  the 
  leaves 
  or 
  cob. 
  The 
  large 
  exit 
  holes 
  of 
  the 
  imago 
  

   are 
  easily 
  detected. 
  The 
  species 
  also 
  attacks 
  millet. 
  

  

  Sesamia 
  calamistis, 
  Hmp. 
  Very 
  similar 
  in 
  its 
  habits 
  to 
  Cirpihis. 
  In 
  young 
  cobs 
  

   the 
  tassel 
  is 
  often 
  attacked, 
  the 
  larvae 
  working 
  downwards 
  into 
  the 
  cob 
  ; 
  it 
  likewise 
  

   feeds 
  oil 
  millet. 
  

  

  Busseola 
  fusca, 
  Hmp. 
  Larvae 
  and 
  pupae 
  were 
  found 
  in 
  the 
  main 
  stalk 
  of 
  millet,, 
  

   but 
  never 
  in 
  great 
  numbers. 
  

  

  Chilo 
  suppressalis, 
  Wlk. 
  This 
  species 
  is 
  the 
  commonest 
  borer 
  of 
  maize 
  and 
  the 
  

   most 
  harmful, 
  as 
  in 
  some 
  instances 
  it 
  will 
  destroy 
  a 
  full 
  half 
  of 
  the 
  crop 
  ; 
  it 
  also 
  

   attacks 
  millet. 
  

  

  Parnara 
  mathias, 
  F. 
  Larvae 
  of 
  this 
  butterfly 
  have 
  been 
  found 
  occasionally 
  

   feeding 
  on 
  the 
  leaves, 
  but 
  as 
  a 
  pest 
  it 
  is 
  insignificant. 
  

  

  Rhynchota. 
  

  

  Peregrinus 
  maidis, 
  Ashm. 
  A 
  field 
  of 
  imported 
  maize 
  (Hickory 
  King) 
  was 
  found 
  

   heavily 
  infested 
  with 
  this 
  cosmopolitan 
  pest 
  ; 
  but 
  the 
  common 
  native 
  variety 
  of 
  

   maize 
  is 
  rarely 
  attacked. 
  

  

  INSECTS 
  INJURIOUS 
  TO 
  VEGETABLES. 
  

  

  Cabbages. 
  

  

  Crocidolomia 
  binotalis, 
  Z. 
  Cabbages 
  are 
  always 
  heavily 
  infested 
  with 
  the 
  larvae 
  

   of 
  this 
  moth 
  and 
  several 
  valuable 
  crops 
  have 
  been 
  completely 
  ruined. 
  Pupation 
  

   takes 
  place 
  on 
  the 
  leaf 
  under 
  a 
  light 
  silken 
  web 
  or 
  in 
  the 
  rolled 
  end 
  of 
  a 
  leaf. 
  The 
  

   pupal 
  stage 
  averages 
  10 
  days. 
  Other 
  food-plants 
  are 
  turnip, 
  watercress, 
  radish 
  

   and 
  nasturtium. 
  

  

  Plutella 
  maculipennis, 
  Curt. 
  The 
  small 
  brilliant 
  green 
  larvae 
  of 
  the 
  diamond- 
  

   back 
  moth 
  were 
  taken 
  in 
  conjunction 
  with 
  those 
  of 
  the 
  former 
  species. 
  Pupae 
  

   are 
  found 
  on 
  the 
  leaf 
  in 
  a 
  silken 
  web. 
  

  

  Phytometra 
  signata, 
  F. 
  This 
  moth 
  is 
  a 
  minor 
  pest. 
  

  

  