﻿ORCHARD 
  IXSECTS 
  PACIFIC 
  XORTITVVEST 
  

  

  Figure 
  3. 
  — 
  Codling 
  moth 
  eggs: 
  A, 
  Nat- 
  

   ural 
  size 
  on 
  apple 
  leaf; 
  B, 
  single 
  egg, 
  

   greatly 
  enlarged. 
  

  

  during 
  June. 
  These 
  worms 
  feed 
  

   in 
  the 
  fruit 
  for 
  about 
  3 
  weeks 
  and 
  

   then 
  leave 
  it 
  and 
  spin 
  cocoons. 
  

   About 
  75 
  percent 
  of 
  them 
  develop 
  

   into 
  pupae 
  and 
  moths, 
  but 
  the 
  

   others 
  remain 
  in 
  the 
  cocoons 
  until 
  

   the 
  following 
  season. 
  The 
  worms 
  

   that 
  transform 
  pass 
  through 
  the 
  

   pupal 
  period 
  in 
  about 
  2 
  weeks, 
  

   and 
  the 
  first 
  individuals 
  of 
  the 
  

   second 
  brood 
  of 
  moths 
  appear 
  

   early 
  in 
  July. 
  

  

  After 
  this 
  time 
  moths 
  are 
  pres- 
  

   ent 
  in 
  large 
  numbers 
  until 
  cool 
  

   weather, 
  and 
  the 
  first 
  stormy 
  

   weather 
  in 
  September 
  usually 
  

   ends 
  their 
  activities 
  for 
  the 
  sea- 
  

   son. 
  Many 
  eggs 
  of 
  the 
  second 
  

   brood 
  are 
  laid 
  on 
  the 
  fruit, 
  and 
  

   during 
  July 
  and 
  August 
  they 
  or- 
  

   dinarily 
  hatch 
  in 
  6 
  or 
  7 
  daj^s. 
  The 
  

   worms 
  often 
  remain 
  in 
  the 
  fruit 
  

   for 
  more 
  than 
  a 
  month 
  in 
  the 
  fall. 
  

  

  and 
  many 
  of 
  them 
  are 
  still 
  there 
  

   when 
  it 
  is 
  picked. 
  They 
  may 
  

   leave 
  the 
  fruit 
  before 
  it 
  is 
  packed, 
  

   and 
  large 
  numbers 
  of 
  cocoons 
  may 
  

   be 
  found 
  in 
  picking 
  boxes 
  and 
  

   packing 
  sheds. 
  

  

  The 
  codling 
  moth 
  is 
  sensitive 
  to 
  

   variations 
  in 
  temperature. 
  In 
  

   warm 
  localities 
  there 
  is 
  often 
  a 
  

   partial 
  third 
  generation, 
  but 
  at 
  

   higher 
  elevations 
  and 
  along 
  the 
  

   coast 
  there 
  is 
  no 
  third 
  generation 
  

   and 
  the 
  second 
  generation 
  is 
  

   smaller 
  than 
  elsewhere. 
  In 
  any 
  

   locality 
  the 
  yearly 
  abundance 
  of 
  

   worms 
  varies 
  greatly, 
  as 
  it 
  is 
  de- 
  

   pendent 
  on 
  weather 
  conditions. 
  

   Temperatures 
  of 
  —15° 
  F. 
  or 
  

   colder 
  kill 
  some 
  of 
  the 
  overwinter- 
  

   ing 
  worms. 
  Probably 
  the 
  effect 
  of 
  

   temperature 
  is 
  most 
  evident 
  dur- 
  

   ing 
  May 
  and 
  June, 
  when 
  large 
  

   numbers 
  of 
  first-brood 
  eggs 
  are 
  

   laid 
  if 
  the 
  weather 
  is 
  warm, 
  but 
  

   the 
  number 
  is 
  greatly 
  reduced 
  if 
  it 
  

   is 
  cold 
  or 
  rainy. 
  Thus 
  an 
  early 
  

   warm 
  season 
  produces 
  many 
  

   worms, 
  but 
  a 
  late 
  cool 
  season 
  has 
  

   the 
  opposite 
  effect. 
  The 
  fruit 
  

   grower 
  should 
  therefore 
  study 
  

   weather 
  conditions 
  as 
  well 
  as 
  con- 
  

   ditions 
  in 
  his 
  orchard 
  and 
  plan 
  his 
  

   spraying 
  schedule 
  accordingly. 
  

  

  CONTROL 
  

  

  Although 
  lead 
  arsenate 
  and 
  

   cryolite 
  have 
  been 
  used 
  for 
  many 
  

   years 
  to 
  control 
  the 
  codling 
  moth, 
  

   the 
  most 
  effective 
  means 
  at 
  present 
  

   consists 
  in 
  spraying 
  the 
  trees 
  one 
  

   or 
  more 
  times 
  with 
  DDT. 
  Other 
  

   organic 
  insecticides 
  may 
  be 
  de- 
  

   veloped 
  for 
  this 
  purpose, 
  and 
  a 
  

   material 
  that 
  will 
  not 
  leave 
  objec- 
  

   tionable 
  residues 
  on 
  the 
  fruit 
  or 
  in 
  

   the 
  soil 
  is 
  needed. 
  For 
  apples 
  two 
  

   to 
  four 
  cover 
  sprays 
  of 
  DDT, 
  

   about 
  3 
  or 
  4 
  weeks 
  apart, 
  will 
  give 
  

   excellent 
  control. 
  The 
  50-percent 
  

   wettable 
  powder 
  should 
  be 
  used 
  at 
  

   the 
  rate 
  of 
  2 
  pounds 
  to 
  100 
  gallons 
  

   in 
  the 
  first 
  cover 
  spray, 
  and 
  at 
  1 
  to 
  

  

  