﻿SMALL 
  MOTH-BORERS 
  OF 
  SUGAR 
  CANE 
  IN 
  BRITISH 
  GUIANA. 
  467 
  

  

  2. 
  Treatment 
  of 
  tops 
  previous 
  to 
  planting 
  by 
  immersion 
  in 
  water 
  for 
  72 
  hours. 
  

   If 
  the 
  tops 
  are 
  so 
  treated 
  there 
  will 
  be 
  no 
  necessity 
  for 
  selection 
  of 
  borer-free 
  tops 
  

   for 
  planting. 
  

  

  3. 
  The 
  destruction 
  of 
  refuse 
  tops 
  and 
  pieces 
  of 
  cane 
  left 
  in 
  the 
  field, 
  either 
  by 
  

   ploughing-in 
  or 
  burning. 
  This 
  would 
  do 
  much 
  to 
  eliminate 
  attacks 
  of 
  weevil 
  (Meta- 
  

   masius 
  hemipterus, 
  L.) 
  and 
  termites, 
  while, 
  if 
  the 
  trash 
  was 
  buried 
  at 
  the 
  same 
  time, 
  

   it 
  would 
  probably 
  have 
  a 
  marked 
  effect 
  on 
  the 
  number 
  of 
  D. 
  canella 
  larvae 
  through 
  

   the 
  destruction 
  of 
  their 
  eggs. 
  

  

  4. 
  The 
  abolition 
  of 
  " 
  stumping 
  " 
  so 
  far 
  as 
  possible. 
  Any 
  " 
  supplying 
  " 
  should 
  

   be 
  done 
  with 
  " 
  tops 
  " 
  soon 
  after 
  planting. 
  

  

  5. 
  The 
  reduction 
  of 
  the 
  acreage 
  under 
  " 
  old 
  canes 
  " 
  to 
  a 
  minimum, 
  and, 
  where 
  

   possible, 
  such 
  old 
  canes 
  not 
  to 
  exceed 
  fourth 
  ratoons. 
  The 
  replanting 
  of 
  at 
  least 
  

   one-fifth 
  of 
  the 
  acreage 
  yearly, 
  such 
  replanting 
  to 
  be 
  carried 
  out 
  in 
  long 
  rested 
  or 
  

   water-fallowed 
  fields 
  and 
  not 
  in 
  fields 
  that 
  have 
  been 
  in 
  continuous 
  cultivation 
  for 
  

   a 
  long 
  period 
  of 
  years. 
  

  

  6. 
  The 
  employment 
  of 
  gangs 
  to 
  collect 
  egg-clusters 
  and 
  larvae 
  of 
  moth-borers 
  

   from 
  the 
  fields. 
  This 
  method 
  of 
  control 
  is 
  still 
  practical 
  in 
  British 
  Guiana 
  and 
  

   should 
  be 
  employed 
  until 
  such 
  other 
  control 
  measures 
  are 
  devised 
  that 
  can 
  supersede 
  it. 
  

  

  7. 
  Returning 
  of 
  parasitised 
  clusters 
  to 
  fields 
  from 
  which 
  they 
  were 
  obtained. 
  

   Where 
  labour 
  conditions 
  allow, 
  the 
  collection 
  of 
  parasitised 
  clusters 
  from 
  fields 
  previous 
  

   to 
  their 
  being 
  reaped, 
  and 
  the 
  distribution 
  of 
  such 
  parasitised 
  clusters 
  amongst 
  the 
  

   fields 
  that 
  most 
  need 
  them. 
  

  

  8. 
  The 
  artificial 
  rearing 
  of 
  the 
  egg-parasites, 
  Trichogramma 
  minutum, 
  Riley, 
  and 
  

   Prophanurus 
  alecto, 
  Cwfd., 
  as 
  well 
  as 
  such 
  larval 
  parasites 
  as 
  Iphiaulax 
  medianus, 
  

   Cam., 
  and 
  the 
  Dexiid 
  fly 
  parasite, 
  is 
  regarded 
  as 
  showing 
  signs 
  of 
  promise 
  as 
  a 
  practical 
  

   means 
  of 
  control. 
  

  

  The 
  investigations 
  described 
  in 
  this 
  paper 
  were 
  carried 
  out 
  during 
  the 
  past 
  

   eighteen 
  months 
  while 
  employed 
  as 
  entomologist 
  to 
  Messrs. 
  S. 
  Davson 
  & 
  Co. 
  Ltd., 
  

   Berbice. 
  I 
  should 
  like 
  to 
  express 
  my 
  thanks 
  to 
  Mr. 
  W. 
  M. 
  B. 
  Shields, 
  and 
  especially 
  

   to 
  Mr. 
  J. 
  R. 
  C. 
  Gordon, 
  as 
  well 
  as 
  to 
  Mr. 
  A. 
  E. 
  De 
  Groot, 
  of 
  that 
  firm, 
  for 
  the 
  facilities 
  

   given 
  me 
  while 
  so 
  employed, 
  and 
  to 
  Mr. 
  J. 
  Crabtree, 
  M.Sc, 
  Superintendent 
  of 
  the 
  

   British 
  Guiana 
  Sugar 
  Planters' 
  Experiment 
  Stations, 
  for 
  the 
  valuable 
  criticisms 
  

   and 
  assistance 
  given 
  throughout 
  the 
  investigations. 
  

  

  Appendix. 
  

  

  J. 
  Crabtree 
  (A 
  Report 
  on 
  Agric. 
  Conditions 
  of 
  Cane-sugar 
  Industry 
  in 
  Brit. 
  

   Guiana, 
  1921) 
  gives 
  the 
  following 
  description 
  of 
  the 
  system 
  employed 
  in 
  this 
  Colony 
  

   in 
  the 
  cultivation 
  of 
  the 
  sugar-cane. 
  The 
  description 
  is 
  given 
  here 
  to 
  enable 
  those 
  

   unacquainted 
  with 
  the 
  system 
  to 
  understand 
  better 
  the 
  practices 
  referred 
  to 
  in 
  this 
  

   paper. 
  

  

  " 
  The 
  process 
  of 
  winning 
  land 
  from 
  the 
  sea, 
  or 
  ' 
  empoldering,' 
  as 
  it 
  is 
  termed, 
  

   consists 
  in 
  surrounding 
  the 
  area 
  to 
  be 
  taken 
  in 
  by 
  dams 
  sufficient^ 
  high 
  to 
  keep 
  

   out 
  surrounding 
  water 
  at 
  any 
  state 
  of 
  the 
  tide. 
  The 
  one 
  in 
  front 
  along 
  the 
  seashore 
  

   is 
  the 
  ' 
  sea 
  dam 
  ' 
  and 
  serves 
  to 
  keep 
  out 
  the 
  sea 
  ; 
  parallel 
  to 
  this 
  at 
  the 
  extreme 
  

   inland 
  limit 
  of 
  the 
  area 
  empoldered 
  is 
  the 
  ' 
  back 
  dam 
  ' 
  keeping 
  out 
  water 
  from 
  the 
  

   savannahs 
  in 
  the 
  wet 
  seasons, 
  and 
  the 
  sides 
  are 
  protected 
  by 
  the 
  dams 
  joining, 
  and 
  

   at 
  right 
  angles 
  to, 
  the 
  two 
  former, 
  thus 
  enclosing 
  a 
  parallelogramatic 
  area 
  which 
  

   becomes 
  the 
  estate. 
  To 
  obtain 
  earth 
  to 
  construct 
  the 
  dams, 
  trenches 
  have 
  to 
  be 
  dug 
  

   on 
  either 
  side 
  of 
  them 
  and 
  the 
  ones 
  on 
  the 
  inside 
  are 
  used 
  as 
  navigation 
  or 
  draining 
  

   trenches, 
  as 
  the 
  case 
  may 
  be. 
  Another 
  dam 
  (with 
  trenches) 
  is 
  made 
  down 
  the 
  middle 
  

   of 
  the 
  estate 
  called 
  the 
  " 
  middle-walk," 
  and 
  at 
  intervals 
  other 
  trenches 
  are 
  cut 
  at 
  

   right 
  angles 
  to 
  these 
  on 
  each 
  side 
  and 
  extending 
  to 
  the 
  sides 
  of 
  the 
  estate, 
  thus 
  dividing 
  

   the 
  latter 
  into 
  square 
  or 
  rectangular 
  fields, 
  access 
  to 
  which 
  is 
  gained 
  by 
  this 
  system 
  

  

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