﻿136 
  PROCEEDI-YGS 
  OF 
  THE 
  FOURTH 
  ENTO^fOLOGICAL 
  MEETING 
  

  

  immunity 
  and 
  also 
  a 
  greater 
  resistance 
  to 
  drought. 
  This 
  will 
  be 
  apparent 
  

   from 
  a 
  reference 
  to 
  the 
  figures 
  published 
  in 
  the 
  Imperial 
  Entomologist's 
  

   Annual 
  Report 
  for 
  1920, 
  pp. 
  73-74. 
  We 
  find 
  therefore 
  that 
  particular 
  

   varieties 
  are 
  suited 
  to 
  particular 
  areas 
  according 
  to 
  differences 
  in 
  local 
  

   climatic 
  conditions. 
  As 
  a 
  rule 
  thick 
  ones 
  do 
  not 
  fare 
  so 
  well 
  in 
  Upper 
  

   and 
  Western 
  India 
  as 
  thin 
  ones. 
  Different 
  varieties 
  of 
  cane 
  show 
  

   different 
  degrees 
  of 
  pest 
  resisting 
  qualities 
  though 
  no 
  variety 
  has 
  yet 
  

   been 
  found 
  to 
  resist 
  pests 
  wholly. 
  

  

  The 
  presence 
  or 
  absence 
  of 
  alternative 
  foodplants 
  in 
  the 
  locality 
  

   is 
  observed 
  to 
  exercise 
  a 
  great 
  influence 
  on 
  the 
  occurrence 
  of 
  at 
  least 
  

   some 
  of 
  the 
  borers 
  in 
  sugarcane. 
  The 
  remarks 
  in 
  this 
  respect 
  on 
  Diatraa 
  

   venosata, 
  Scirpophaga 
  scanthogasfrella 
  and 
  the 
  Noctuid 
  borer 
  C. 
  S. 
  1666 
  

   may 
  be 
  seen. 
  

  

  The 
  attempts 
  at 
  dealing 
  with 
  the 
  borer 
  pests 
  of 
  sugarcane 
  and 
  external 
  

   agents 
  of 
  damage 
  which 
  work 
  with 
  effects 
  similar 
  to 
  those 
  produced 
  

   by 
  the 
  borers 
  must 
  take 
  into 
  consideration 
  the 
  following 
  points 
  : 
  — 
  

  

  (1) 
  The 
  suitability 
  or 
  otherwise 
  of 
  the 
  cane 
  itself 
  to 
  the 
  climatic 
  

  

  conditions 
  of 
  the 
  place 
  where 
  it 
  is 
  grown. 
  

  

  (2) 
  The 
  habits 
  of 
  the 
  cane, 
  especially 
  its 
  capacity 
  for 
  tillering 
  

  

  during 
  the 
  early 
  stages 
  of 
  its 
  growth, 
  as 
  varieties 
  which 
  

   tiller 
  well 
  show 
  much 
  greater 
  immunity 
  than 
  those 
  in 
  which 
  

   tillering 
  is 
  poor. 
  

  

  (3) 
  The 
  drought-resisting 
  quality 
  of 
  the 
  cane, 
  especially 
  in 
  places 
  

  

  where 
  no 
  irrigation 
  is 
  practised. 
  

  

  (4) 
  The 
  natural 
  immunity 
  of 
  the 
  cane 
  against 
  pests 
  and 
  diseases 
  

  

  and 
  (5) 
  the 
  effect 
  of 
  the 
  presence 
  or 
  absence 
  of 
  alternative 
  

   foodplants 
  of 
  the 
  different 
  borers. 
  

  

  The 
  borer 
  problem 
  is 
  not 
  so 
  acute 
  at 
  Coimbatore 
  and 
  other 
  places 
  

   in 
  Southern 
  India 
  with 
  favourable 
  climatic 
  conditions 
  as 
  in 
  Northern 
  

   India 
  where 
  in 
  many 
  places, 
  such 
  as 
  Pusa, 
  thick 
  canes 
  yield 
  about 
  50 
  

   per 
  cent, 
  less 
  than 
  they 
  are 
  capable 
  of 
  yielding. 
  As 
  described 
  in 
  the 
  

   first 
  paper, 
  only 
  one 
  out 
  of 
  every 
  four 
  shoots 
  which 
  grow 
  of 
  such 
  canes 
  

   comes 
  to 
  be 
  harvested, 
  the 
  other 
  three 
  being 
  killed. 
  Therefore 
  the 
  

   problem 
  for 
  such 
  areas 
  seems 
  to 
  be 
  to 
  evolve 
  a 
  variety 
  of 
  sugarcane 
  

   which 
  can 
  be 
  planted 
  at 
  the 
  time 
  of 
  the 
  breaking 
  of 
  the 
  monsoon 
  or 
  

   even 
  after, 
  but 
  which 
  will 
  ripen 
  at 
  the 
  time 
  when 
  canes 
  do 
  now-a-days. 
  

   This 
  can 
  probably 
  be 
  done 
  by 
  selection 
  of 
  the 
  tillers 
  which 
  grow 
  late 
  

   but 
  ripen 
  along 
  with 
  the 
  mother 
  canes. 
  

  

  If 
  this 
  be 
  possible 
  the 
  borer 
  question 
  can 
  be 
  solved 
  to 
  a 
  very 
  great 
  

   extent 
  for 
  localities 
  with 
  adverse 
  climatic 
  conditions 
  such 
  as 
  Upper 
  

   India. 
  

  

  