﻿U. 
  S. 
  D. 
  A., 
  B. 
  E. 
  Bui. 
  116, 
  Part 
  IV. 
  D. 
  F. 
  1. 
  1., 
  Issued 
  January 
  17, 
  1913. 
  

  

  PAPERS 
  ON 
  DECIDUOUS 
  FRUIT 
  INSECTS 
  AND 
  INSECTICIDES. 
  

  

  LIME-SULPHUR 
  AS 
  A 
  STOMACH 
  POISON 
  FOR 
  INSECTS. 
  

  

  By 
  E. 
  W. 
  Scott 
  and 
  E. 
  H. 
  Siegler, 
  

   Entomological 
  Assistants, 
  Deciduous 
  Fruit 
  Insect 
  Investigations. 
  

  

  INTRODUCTION. 
  

  

  During 
  the 
  season 
  of 
  1912 
  the 
  branch 
  of 
  Deciduous 
  Fruit 
  Insect 
  

   Investigations 
  of 
  the 
  Bureau 
  of 
  Entomology, 
  at 
  its 
  laboratory 
  at 
  

   Benton 
  Harbor, 
  Mich., 
  conducted 
  a 
  series 
  of 
  feeding 
  experiments 
  to 
  

   test 
  the 
  killing 
  effect 
  of 
  various 
  poisons 
  on 
  different 
  species 
  of 
  insects. 
  

   In 
  the 
  course 
  of 
  the 
  work 
  it 
  was 
  soon 
  noted 
  that 
  lime-sulphur, 
  when 
  

   combined 
  with 
  certain 
  slow-acting 
  arsenicals 
  and 
  doubtful 
  stomach 
  

   poisons, 
  increased 
  their 
  insecticidal 
  value. 
  This 
  clue 
  was 
  followed 
  

   up 
  and 
  a 
  considerable 
  series 
  of 
  feeding 
  tests 
  was 
  made 
  during 
  the 
  

   succeeding 
  months. 
  These 
  experiments 
  indicate 
  that 
  lime-sulphur 
  

   spray 
  alone, 
  at 
  the 
  strength 
  used 
  in 
  spraying 
  orchards 
  in 
  foliage, 
  

   has 
  a 
  decided 
  insecticidal 
  action 
  as 
  a 
  stomach 
  poison. 
  It 
  will 
  be 
  

   remembered 
  that 
  lime-sulphur 
  as 
  an 
  insecticide 
  has 
  been 
  heretofore 
  

   considered 
  solely 
  as 
  a 
  contact 
  spray. 
  In 
  this 
  paper 
  are 
  given 
  the 
  

   results 
  obtained 
  from 
  the 
  use 
  of 
  lime-sulphur 
  and 
  arsenate 
  of 
  lead, 
  

   separately 
  and 
  in 
  combination. 
  

  

  CONDITIONS 
  OF 
  THE 
  EXPERIMENTS. 
  

  

  The 
  fall 
  webworm 
  (Ilyphantria 
  cunea 
  Drury) 
  (see 
  Plate 
  XI) 
  was 
  

   used 
  for 
  most 
  of 
  the 
  feeding 
  tests, 
  since 
  this 
  insect 
  was 
  readily 
  obtained 
  

   in 
  large 
  numbers. 
  Furthermore, 
  it 
  was 
  easily 
  handled, 
  was 
  rather 
  

   resistant 
  to 
  poisons, 
  and 
  on 
  the 
  whole 
  proved 
  an 
  ideal 
  species 
  for 
  the 
  

   work 
  at 
  hand. 
  The 
  stock 
  supply 
  was 
  collected 
  in 
  the 
  field 
  and 
  brought 
  

   to 
  the 
  laboratory 
  where 
  the 
  tests 
  were 
  made. 
  Only 
  the 
  very 
  young 
  

   larva?, 
  usually 
  three 
  or 
  four 
  days 
  old, 
  were 
  used, 
  and 
  whenever 
  pos- 
  

   sible 
  those 
  from 
  the 
  same 
  nest 
  were 
  used 
  for 
  the 
  same 
  experiment. 
  

   When 
  two 
  or 
  more 
  nests 
  of 
  larvae 
  were 
  necessary 
  for 
  use 
  in 
  a 
  given 
  

   experiment, 
  care 
  was 
  taken 
  to 
  use 
  those 
  of 
  as 
  nearly 
  the 
  same 
  age 
  

   as 
  possible. 
  

  

  The 
  wild 
  black 
  cherry 
  (PrUMbS 
  8erotina) 
  was 
  found 
  to 
  be 
  a 
  favorite 
  

   food 
  plant 
  of 
  the 
  fall 
  webworm 
  in 
  Michigan. 
  In 
  addition, 
  the 
  folingo 
  

   stood 
  up 
  well 
  when 
  the 
  branches 
  were 
  placed 
  in 
  water, 
  and, 
  further, 
  

  

  09429°-! 
  3 
  81 
  

  

  