﻿THE 
  BEAN 
  THRIPS. 
  

  

  (Helio 
  thrips 
  fasciatus 
  Pergande.) 
  

  

  INTRODUCTION. 
  

  

  In 
  the 
  State 
  of 
  California 
  during 
  the 
  past 
  four 
  or 
  five 
  years 
  the 
  

   bean 
  thrips 
  has 
  been 
  reported 
  with 
  increasing 
  frequency 
  as 
  a. 
  serious 
  

   pest 
  to 
  various 
  crops. 
  The 
  common 
  name 
  " 
  bean 
  thrips 
  " 
  is 
  somewhat 
  

   of 
  a 
  misnomer, 
  as 
  this 
  insect 
  feeds 
  on 
  many 
  different 
  crops, 
  but 
  is 
  re- 
  

   tained 
  here, 
  as 
  it 
  is 
  well 
  known 
  by 
  that 
  name 
  in 
  California. 
  That 
  

   State, 
  with 
  its 
  long, 
  dry 
  summer, 
  furnishes 
  climatic 
  conditions 
  un- 
  

   usually 
  favorable 
  to 
  the 
  development 
  of 
  thrips, 
  and 
  several 
  species 
  

   have 
  gained 
  such 
  a 
  foothold 
  there 
  as 
  annually 
  to 
  cause 
  a 
  loss 
  of 
  hun- 
  

   dreds 
  of 
  thousands 
  of 
  dollars. 
  

  

  In 
  the 
  summer 
  of 
  1909, 
  Mr. 
  R. 
  S. 
  Woglum, 
  of 
  the 
  Bureau 
  of 
  En- 
  

   tomology, 
  informed 
  the 
  author 
  that 
  during 
  the 
  summer 
  before 
  he 
  had 
  

   seen 
  hundreds 
  of 
  acres 
  of 
  beans 
  in 
  southern 
  California 
  so 
  seriously 
  

   infested 
  by 
  the 
  bean 
  thrips 
  that 
  they 
  had 
  the 
  appearance 
  of 
  plants 
  

   scorched 
  by 
  fire 
  ; 
  and 
  as 
  this 
  thrips 
  seemed 
  to 
  be 
  increasing 
  in 
  num- 
  

   bers 
  and 
  destructiveness 
  it 
  appeared 
  to 
  be 
  the 
  part 
  of 
  wisdom 
  to 
  

   obtain 
  all 
  possible 
  information 
  concerning 
  its 
  life 
  history 
  and 
  control 
  

   before 
  it 
  reached 
  the 
  enormous 
  abundance 
  of 
  the 
  destructive 
  pear 
  

   thrips 
  (Euthrips 
  pyri 
  Daniel). 
  When, 
  therefore, 
  the 
  Bureau 
  of 
  

   Entomology 
  established 
  a 
  field 
  station 
  at 
  Compton, 
  CaL, 
  in 
  Septem- 
  

   ber, 
  1909, 
  for 
  the 
  study 
  of 
  truck-crop 
  ard 
  sugar-beet 
  insects, 
  the 
  

   writer 
  planned, 
  among 
  other 
  projects, 
  to 
  undertake 
  as 
  complete 
  a 
  

   study 
  of 
  this 
  insect 
  as 
  time 
  would 
  permit. 
  With 
  this 
  in 
  mind, 
  the 
  

   bean 
  thrips 
  has 
  been 
  the 
  subject 
  of 
  thorough 
  investigation 
  during 
  the 
  

   years 
  1910 
  and 
  1911. 
  During 
  this 
  time, 
  however, 
  the 
  insect 
  was 
  not 
  

   again 
  so 
  destructive 
  to 
  beans, 
  so 
  that 
  remedies 
  with 
  spray 
  mixtures 
  

   could 
  not 
  be 
  thoroughly 
  tested. 
  Nevertheless, 
  as 
  the 
  life 
  history 
  has 
  

   been 
  worked 
  out 
  and 
  a 
  large 
  fund 
  of 
  information 
  obtained 
  on 
  the 
  dis- 
  

   tribution 
  and 
  habits 
  of 
  this 
  thrips, 
  together 
  with 
  knowledge 
  of 
  a 
  

   natural 
  enemy 
  of 
  some 
  promise, 
  this 
  paper 
  is 
  published 
  at 
  the 
  present 
  

   time. 
  

  

  At 
  Compton, 
  in 
  Los 
  Angeles 
  County, 
  where 
  the 
  life 
  history 
  of 
  this 
  

   insect 
  was 
  studied 
  by 
  the 
  writer, 
  the 
  temperature 
  is 
  quite 
  cool, 
  since 
  

   the 
  location 
  is 
  near 
  the 
  coast. 
  

  

  7 
  

  

  