﻿200 
  W. 
  A. 
  LAMBORN. 
  — 
  THE 
  AGRICULTURAL 
  PESTS 
  

  

  Insect 
  Pests 
  attacking 
  Cotton 
  Roots. 
  

  

  The 
  larvae 
  of 
  a 
  Lamellicorn 
  beetle, 
  recorded 
  for 
  the 
  first 
  time 
  in 
  1910 
  by 
  Jemmett- 
  

   as 
  attacking 
  cotton 
  roots, 
  were 
  responsible 
  for 
  the 
  loss 
  of 
  a 
  number 
  of 
  plants. 
  The 
  

   symptoms 
  of 
  their 
  presence 
  were 
  a 
  gradual 
  withering 
  of 
  the 
  leaves, 
  which 
  then 
  turned 
  

   red 
  and 
  fell, 
  a 
  slow 
  drying 
  of 
  the 
  stem, 
  premature 
  opening 
  of 
  the 
  bolls, 
  and 
  ultimate 
  

   death 
  of 
  the 
  plant. 
  The 
  roots 
  of 
  the 
  plant 
  were 
  then 
  found 
  to 
  be 
  decorticated, 
  and 
  

   there 
  was 
  usually 
  a 
  redundancy 
  of 
  new 
  tissue 
  at 
  the 
  junction 
  of 
  the 
  healthy 
  and 
  

   attacked 
  parts. 
  

  

  With 
  a 
  view 
  to 
  combating 
  the 
  pest, 
  experiments 
  in 
  the 
  application 
  of 
  a 
  1 
  in 
  200* 
  

   aqueous 
  solution 
  of 
  carbon 
  bisulphide 
  to 
  the 
  roots 
  by 
  means 
  of 
  the 
  Gastine 
  apparatus 
  

   were 
  undertaken 
  in 
  collaboration 
  with 
  the 
  Assistant 
  Director 
  of 
  the 
  Department, 
  and 
  

   the 
  results 
  were 
  distinctly 
  promising, 
  some 
  plants 
  which 
  were 
  apparently 
  dying 
  having 
  

   subsequently 
  put 
  out 
  new 
  leaves 
  and 
  recommenced 
  to 
  grow. 
  The 
  plot 
  of 
  cotton 
  

   especially 
  attacked 
  by 
  this 
  pest 
  had 
  borne 
  a 
  similar 
  crop 
  in 
  the 
  previous 
  season. 
  

   Doubtless 
  the 
  loss 
  would 
  have 
  been 
  less 
  had 
  there 
  been 
  a 
  change 
  of 
  the 
  crop 
  on 
  it, 
  

   for 
  the 
  beetles 
  and 
  their 
  larvae 
  possibly 
  he 
  dormant 
  in 
  the 
  ground 
  during 
  the 
  

   unfavourable 
  conditions 
  of 
  the 
  dry 
  season. 
  

  

  Insects 
  attacking 
  Cotton 
  Bolls. 
  

  

  The 
  red 
  bollworm, 
  Diparopsis 
  castanea, 
  Hmp., 
  occurred 
  abundantly. 
  The 
  life- 
  

   history 
  of 
  this 
  well-known 
  insect 
  has 
  already 
  been 
  worked 
  out 
  by 
  several 
  entomolo- 
  

   gists, 
  and 
  my 
  observations 
  accord 
  with 
  what 
  I 
  have 
  read, 
  but 
  there 
  is 
  one 
  important 
  

   feature 
  characteristic 
  of 
  the 
  insect 
  in 
  Nigeria, 
  namely, 
  that 
  whereas 
  in 
  the 
  majority 
  

   of 
  cases 
  pupation 
  lasts 
  eight 
  to 
  ten 
  days, 
  yet 
  a 
  small 
  number 
  of 
  instances 
  occur 
  in 
  

   which 
  the 
  pupa 
  may 
  lie 
  dormant 
  in 
  the 
  ground 
  for 
  many 
  months. 
  Some 
  of 
  these 
  

   bollworms 
  which 
  buried 
  themselves 
  in 
  earth 
  in 
  my 
  laboratory 
  in 
  October 
  were 
  still 
  

   in 
  late 
  May, 
  when 
  I 
  came 
  away, 
  in 
  the 
  resting 
  pupa 
  condition, 
  though 
  moving 
  actively 
  

   at 
  a 
  touch, 
  obviously 
  a 
  provision 
  of 
  nature 
  to 
  ensure 
  the 
  preservation 
  of 
  the 
  species- 
  

   through 
  the 
  adverse 
  conditions 
  of 
  the 
  dry 
  season. 
  

  

  The 
  life-history 
  of 
  Earias 
  biplaga, 
  Walk., 
  the 
  other 
  common 
  bollworm, 
  was 
  not 
  

   definitely 
  worked 
  out, 
  though 
  larvae 
  of 
  all 
  ages 
  were 
  from 
  time 
  to 
  time 
  found 
  not 
  only 
  

   in 
  bolls, 
  but 
  at 
  an 
  earlier 
  stage 
  in 
  flower-buds. 
  They 
  were 
  found 
  also 
  feeding 
  on 
  the 
  

   eaves 
  and 
  in 
  the 
  seed-pods 
  of 
  the 
  fibre 
  plant, 
  Sida 
  carpinifolia, 
  L., 
  also 
  of 
  the 
  family 
  

   Malvaceae, 
  as 
  well 
  as 
  on 
  the 
  leaves 
  of 
  several 
  bush 
  plants. 
  

  

  The 
  full-fed 
  larva, 
  which 
  measures 
  about 
  £ 
  inch 
  in 
  length, 
  is 
  dull 
  brown 
  in 
  colour 
  

   and 
  is 
  characterised 
  by 
  the 
  presence 
  of 
  four 
  pointed 
  tubercles 
  on 
  each 
  segment, 
  so 
  

   situated 
  as 
  to 
  form 
  dorsal 
  and 
  sublateral 
  longitudinal 
  rows. 
  The 
  colour 
  of 
  the 
  larva, 
  

   the 
  presence 
  of 
  these 
  tubercles, 
  and 
  the 
  fact 
  that 
  it 
  is 
  often 
  found 
  as 
  a 
  leaf-eater 
  seem 
  

   to 
  indicate 
  that 
  its 
  boll-boring 
  propensities 
  are 
  a 
  recent 
  development, 
  probably 
  

   dating 
  from 
  the 
  cultivation 
  on 
  a 
  large 
  scale 
  of 
  cotton 
  in 
  the 
  country. 
  

  

  Though 
  no 
  natural 
  enemies 
  were 
  discovered 
  in 
  the 
  case 
  of 
  Diparopsis, 
  a 
  species 
  of 
  

   Eumenid 
  wasp, 
  Rhynchium 
  ventrale, 
  Sauss., 
  a 
  black 
  insect 
  with 
  a 
  red 
  tip 
  to 
  its. 
  

   abdomen, 
  was 
  found 
  to 
  act 
  asan 
  important 
  check 
  on 
  Earias. 
  This 
  Eumenid 
  was 
  for 
  a 
  

   very 
  long 
  time 
  confused 
  by 
  myself 
  with 
  other 
  very 
  similar 
  insects, 
  Synagris 
  calida, 
  

   L., 
  S. 
  spiniventris, 
  111., 
  and 
  Rhynchium 
  synagroides, 
  Sauss., 
  until 
  I 
  noticed 
  a 
  wasp 
  

   on 
  the 
  wing 
  carrying 
  an 
  Earias 
  larva. 
  It 
  was 
  seen 
  to 
  enter 
  a 
  cylindrical 
  tube 
  of 
  mud 
  

  

  