﻿THE 
  GKAPE-BERKY 
  MOTH. 
  

  

  39 
  

  

  Table 
  XIV. 
  — 
  Length 
  of 
  the 
  feeding 
  period 
  of 
  second-brood 
  larvae 
  of 
  the 
  grape-berry 
  moth 
  

   in 
  fruit 
  on 
  the 
  vines 
  under 
  large 
  outdoor 
  rearing 
  cages, 
  North 
  East, 
  Pa., 
  1909. 
  

  

  Number 
  

   of 
  larvae. 
  

  

  Larvae 
  

   hatched. 
  

  

  Aug. 
  25 
  

  

  ...do 
  

  

  ...do 
  

  

  ...do 
  

  

  ...do 
  

  

  ...do 
  

  

  ...do 
  

  

  ...do 
  

  

  ...do 
  

  

  ...do 
  

  

  Larvae 
  

   left 
  fruit. 
  

  

  Sept. 
  25 
  

   Sept. 
  26 
  

   Sept. 
  27 
  

   Sept. 
  28 
  

   Sept. 
  29 
  

   Oct. 
  2 
  

   Oct. 
  3 
  

   Oct. 
  4 
  

   Oct. 
  5 
  

   Oct. 
  6 
  

  

  Number 
  

   of 
  days. 
  

  

  Number 
  

   of 
  larvae. 
  

  

  Larvae 
  

   hatched. 
  

  

  Aug. 
  25 
  

  

  ..do 
  

  

  ..do 
  

  

  ..do 
  

  

  ..do 
  

  

  ..do 
  

  

  Larvae 
  

   left 
  fruit. 
  

  

  Number 
  

   of 
  days. 
  

  

  Oct. 
  7 
  

  

  Oct. 
  8 
  

  

  Oct. 
  9 
  

  

  Oct. 
  10 
  

  

  Oct. 
  11 
  

  

  Oct. 
  17 
  

  

  Average 
  . 
  . 
  . 
  

   Maximum 
  

  

  Minimum. 
  

  

  43 
  

  

  44 
  

   45 
  

   46 
  

   47 
  

   53 
  

   40.3 
  

   53 
  

   31 
  

  

  The 
  infested 
  grape 
  clusters 
  were 
  removed 
  from 
  the 
  cage 
  just 
  

   before 
  the 
  larvae 
  were 
  ready 
  to 
  leave 
  the 
  berries. 
  These 
  larvae 
  

   hatched 
  from 
  eggs 
  deposited 
  between 
  August 
  20 
  and 
  25. 
  It 
  was 
  

   impossible 
  to 
  determine 
  the 
  exact 
  date 
  of 
  hatching 
  of 
  all 
  of 
  the 
  eggs, 
  

   but 
  only 
  a 
  very 
  small 
  number 
  hatched 
  previous 
  to 
  August 
  25 
  and 
  

   this 
  may 
  account 
  in 
  a 
  measure 
  for 
  the 
  shorter 
  average 
  period 
  of 
  

   feeding 
  than 
  is 
  recorded 
  for 
  the 
  larvae 
  from 
  the 
  stock 
  jars. 
  In 
  addi- 
  

   tion 
  to 
  this 
  all 
  but 
  one 
  of 
  these 
  larvae 
  had 
  left 
  the 
  fruit 
  previous 
  to 
  

   the 
  occurrence 
  of 
  a 
  decided 
  drop 
  in 
  temperature 
  between 
  October 
  

   12 
  and 
  20, 
  whereas 
  only 
  two 
  of 
  the 
  larvae 
  had 
  emerged 
  from 
  the 
  

   fruit 
  in 
  the 
  stock 
  jars. 
  Hence, 
  since 
  insect 
  activities 
  were 
  slight 
  

   during 
  this 
  cold 
  wave 
  the 
  period 
  spent 
  in 
  the 
  fruit 
  by 
  those 
  larvae 
  

   which 
  had 
  not 
  escaped 
  previous 
  to 
  its 
  occurrence 
  was 
  abnormally 
  

   prolonged. 
  

  

  The 
  minimum 
  period 
  spent 
  in 
  fruit 
  by 
  larvae 
  in 
  the 
  rearing 
  cage 
  

   was 
  31 
  days 
  as 
  against 
  40 
  days 
  by 
  those 
  in 
  stock 
  jars; 
  the 
  average 
  

   40.3 
  days 
  as 
  against 
  52.6 
  days, 
  and 
  the 
  maximum 
  53 
  days 
  as 
  against 
  

   63 
  days. 
  

  

  Date 
  second-brood 
  larvse 
  leave 
  fruit. 
  — 
  A 
  record 
  was 
  made 
  of 
  the 
  period 
  

   during 
  which 
  the 
  larvae 
  leave 
  the 
  berries, 
  with 
  a 
  view 
  to 
  ascertaining 
  

   whether 
  many 
  of 
  them 
  are 
  likely 
  to 
  be 
  removed 
  from 
  the 
  vineyard 
  

   when 
  the 
  ripe 
  grapes 
  are 
  being 
  marketed. 
  A 
  large 
  number 
  of 
  larvae 
  

   which 
  infested 
  grape 
  clusters 
  were 
  collected 
  from 
  vineyards 
  August 
  

   20-24. 
  At 
  this 
  date 
  few 
  if 
  any 
  of 
  the 
  larvae 
  of 
  the 
  second 
  brood 
  

   had 
  fully 
  matured. 
  Since 
  the 
  emergence 
  of 
  the 
  two 
  broods 
  of 
  moths 
  

   overlap 
  it 
  is 
  quite 
  likely 
  that 
  some 
  of 
  the 
  larvae 
  in 
  this 
  record 
  belong 
  

   to 
  the 
  first 
  brood. 
  Daily 
  examinations 
  of 
  the 
  collected 
  material 
  

   were 
  made 
  and 
  the 
  record 
  of 
  the 
  larvae 
  leaving 
  the 
  fruit 
  is 
  given 
  in 
  

   Table 
  XV. 
  

  

  