﻿204 
  W. 
  A. 
  LAMBORN. 
  — 
  THE 
  AGRICULTURAL 
  PESTS 
  

  

  second 
  leaf-eating 
  beetle, 
  found 
  in 
  some 
  numbers 
  in 
  the 
  early 
  morning 
  was 
  a 
  

   Melolonthid, 
  Trochalus 
  carinatus, 
  Schonh. 
  

  

  A 
  species 
  of 
  basket 
  worm, 
  the 
  larva 
  of 
  the 
  Psychid 
  moth, 
  Metisa 
  sierricola, 
  White, 
  

   (Plate 
  xxiii), 
  was 
  to 
  be 
  found 
  occasionally 
  eating 
  cacao 
  leaves. 
  The 
  wonderful 
  power 
  

   possessed 
  by 
  the 
  legless, 
  wingless 
  females 
  of 
  this 
  family 
  of 
  attracting 
  the 
  males 
  was 
  

   repeatedly 
  shown 
  by 
  the 
  assembling 
  of 
  males, 
  often 
  to 
  the 
  number 
  of 
  forty 
  or 
  fifty 
  

   and 
  always 
  in 
  the 
  early 
  morning, 
  to 
  a 
  newly 
  emerged 
  captive 
  female. 
  

  

  The 
  caterpillar 
  of 
  the 
  Arctiid 
  moth, 
  Diacrisia 
  maculosa, 
  Cram., 
  was 
  also 
  found 
  

   attacking 
  the 
  leaves, 
  and 
  is 
  probably 
  the 
  most 
  important 
  pest 
  next 
  to 
  Adoretus. 
  

   The 
  larvae 
  of 
  a 
  small 
  Noctuid 
  moth, 
  Earias 
  citrina, 
  Saalm., 
  were 
  also 
  observed 
  on 
  

   the 
  leaves 
  of 
  young 
  cacao 
  plants. 
  Though 
  larvae 
  of 
  the 
  Hesperid, 
  Rhopalocampta 
  

   forestan, 
  Cram., 
  have 
  been 
  recorded 
  as 
  cacao 
  leaf 
  pests 
  in 
  Nigeria, 
  they 
  were 
  not 
  in 
  

   evidence 
  on 
  cacao 
  during 
  the 
  past 
  season, 
  though 
  they 
  were 
  collected 
  in 
  large 
  numbers 
  

   from 
  a 
  bush 
  plant 
  by 
  the 
  Eumenid 
  wasp, 
  Synagris 
  spiniventris, 
  111., 
  which 
  stores 
  them 
  

   exclusively 
  as 
  food 
  for 
  its 
  larvae. 
  The 
  red 
  tree 
  ant, 
  Oecophylla 
  smaragdina 
  longinoda, 
  

   Latr., 
  which 
  occurred 
  on 
  the 
  larger 
  plants 
  abundantly 
  and 
  is 
  highly 
  combative, 
  

   probably 
  plays 
  a 
  most 
  useful 
  part 
  in 
  keeping 
  off 
  the 
  various 
  insect 
  pests 
  other 
  than 
  

   Coccidae. 
  Its 
  presence 
  probably 
  accounts 
  for 
  the 
  fact 
  that 
  only 
  young 
  plants 
  which 
  

   it 
  does 
  not 
  frequent, 
  are 
  attacked 
  by 
  leaf 
  pests, 
  for 
  the 
  latter 
  do 
  not 
  cause 
  appreciable 
  

   damage 
  to 
  older 
  and 
  well 
  established 
  plants. 
  

  

  In 
  regard 
  to 
  the 
  measures 
  adopted 
  against 
  the 
  leaf-eaters, 
  in 
  the 
  wet 
  season 
  the 
  

   plants 
  were 
  dusted 
  with 
  a 
  mixture 
  of 
  Paris 
  green 
  and 
  lime, 
  a 
  measure 
  attended 
  with 
  

   good 
  results. 
  Later 
  on, 
  spraying 
  with 
  chromate 
  of 
  lead 
  solution 
  was 
  adopted 
  instead, 
  

   owing 
  to 
  the 
  liability 
  of 
  Paris 
  green 
  to 
  scorch 
  the 
  young 
  and 
  tender 
  leaves. 
  

  

  Insects 
  attacking 
  the 
  Stems. 
  

  

  The 
  only 
  stem-borers 
  found 
  were 
  the 
  larvae 
  of 
  the 
  Megalopygid 
  moth, 
  Eulophonotus 
  

   myrmeleon, 
  Feld. 
  (Plate 
  xvii, 
  figs. 
  7, 
  9), 
  the 
  only 
  representative 
  of 
  the 
  Megalopygidae 
  

   known 
  to 
  occur 
  outside 
  America. 
  The 
  larvae 
  usually 
  tunnel 
  medium-sized 
  branches, 
  

   causing 
  a 
  gradual 
  impairment 
  of 
  vitality, 
  so 
  that 
  the 
  leaves 
  droop, 
  then 
  wither 
  and 
  

   fall, 
  and 
  the 
  branch 
  itself 
  ultimately 
  blackens 
  and 
  dies. 
  The 
  cause 
  of 
  the 
  condition 
  is 
  

   readily 
  determined 
  by 
  finding 
  at 
  the 
  junction 
  of 
  the 
  healthy 
  and 
  diseased 
  parts 
  of 
  the 
  

   branch 
  a 
  circular 
  orifice, 
  covered 
  up 
  with 
  sawdust-like 
  droppings 
  held 
  together 
  with 
  

   silk, 
  which 
  leads 
  into 
  a 
  tunnel 
  containing 
  a 
  white 
  maggot-like 
  larva 
  or 
  a 
  brown, 
  spiny 
  

   pupa. 
  It 
  is 
  unusual 
  for 
  the 
  main 
  stem 
  to 
  be 
  attacked. 
  In 
  the 
  Onipe 
  district, 
  about 
  

   15 
  miles 
  due 
  south 
  of 
  Ibadan, 
  this 
  species 
  occurred 
  in 
  abundance, 
  nearly 
  every 
  tree 
  

   yielding 
  one 
  or 
  two 
  specimens. 
  

  

  These 
  boring 
  pests 
  are 
  well 
  known 
  to 
  the 
  farmers 
  in 
  the 
  cacao-growing 
  district, 
  

   and 
  it 
  is 
  their 
  practice 
  to 
  lop 
  affected 
  branches, 
  leaving 
  them 
  on 
  the 
  ground. 
  This 
  

   probably 
  makes 
  little 
  difference 
  to 
  the 
  well-being 
  of 
  the 
  borers, 
  which 
  can 
  thrive 
  in 
  

   freshly 
  dead 
  wood 
  if 
  moisture 
  is 
  present, 
  so 
  that 
  to 
  destroy 
  the 
  pests 
  it 
  is 
  necessary 
  

   to 
  burn 
  such 
  branches 
  ; 
  though 
  if 
  found 
  before 
  much 
  damage 
  is 
  done, 
  an 
  easy 
  method 
  

   js 
  to 
  push 
  a 
  flexible 
  wire 
  up 
  the 
  tunnels, 
  subsequently 
  plugging 
  and 
  tarring 
  the 
  hole. 
  

   With 
  a 
  view 
  to 
  killing 
  the 
  larvae 
  tunnelling 
  in 
  main 
  stems, 
  injections 
  of 
  carbon 
  

   bisulphide 
  were 
  made 
  into 
  the 
  bore-holes 
  and 
  they 
  were 
  then 
  immediately 
  plugged 
  

   with 
  a 
  pellet 
  of 
  clay 
  and 
  tarred. 
  This 
  measure 
  also 
  seemed 
  to 
  be 
  attended 
  with 
  

   good 
  results. 
  

  

  