Jan.  2, 1893.] 
THE  TROPICAL  AGRICULTURIST. 
483 
cheaper.  Bubach  sells  in  the  drug  stores  for  about 
seventy-five  cents  per  pound,  while  the  Persian 
Insect  Powder  sells  at  thirty-five  cents. 
Pyrethrum  belongs  to  the  external  contact  class 
of  insecticides,  and  kills  by  closing  the  breathing 
pores  of  the  insects.  It  is  a perfectly  harmless 
substance,  not  being  poisonous  in  any  way,  and 
for  this  reason  is  most  used  to  kill  insects  upon 
plants  where  we  would  not  wish  to  apply  poisons. 
Hence  it  makes  an  excellent  remedy  to  kill  the 
green  worms  upon  cabbage  plants,  and  is  largely 
used  for  this  purpose.  It  can  be  applied  dry  by 
means  of  a hand  bellows,  or  mixed  with  water,  a 
tablespoonful  to  the  pail,  and  applied  with  a com- 
mon sprinkler  or  a force  pump.  When  applied  dry 
it  can  be  advantageously  mixed  with  three  times 
its  bulk  of  flour,  it  is  a good  application  for  plant 
lice  when  applied  as  a liquid. 
Tobacco  belongs  to  the  external  contact  class  of 
insecticides,  and  is  used  to  destroy  plant  lice, 
various  caterpillars,  and  lice  upon  domestic  animals. 
It  consists  of  the  powdered  leaves  and  stems  of 
the  tobacco  plant,  and  may  be  applied  in  the  same 
manner  as  pyrethrum.  Refuse  tobacco  can  be 
obtained  through  a drug  store  at  a cost  of  little 
more  than  the  freight,  and  this  if  ground  or  cut 
into  small  pieces  will  make  an  excellent  insecticide 
for  many  purposes.  When  the  tobacco  is  used  to 
destroy  lice  upon  domestic  annuals  it  is  applied  by 
washing  the  skin  with  a decoction  made  by  soaking 
or  boiling  the  tobacco  in  water.  Tobacco  is  also 
useful  as  a repellant  whereby  insects  are  kept  away 
from  plants ; e.g.,  by  putting  it  upon  cucumber  hills 
the  striped  cucumber  beetle  may  be  kept  away. 
Hellebore  kills  by  both  external  and  internal  con- 
tact, and,  hence,  in  some  cases  is  a very  useful 
insecticide.  It  is  a vegetable  poison,  consisting  of 
the  powdered  roots  of  the  white  hellebore  plant.  It 
is  applied  in  the  same  manner  as  pyrethrum,  and 
sells  at  about  twenty-five  cents  a pound.  Hellebore 
is  specially  used  for  the  well-known  imported 
currant  worm. 
Paris  green  is  an  arsenite  of  oopper,  and  contains 
about  fifty-five  per  cent,  of  arsenic,  the  proportion 
being  somewhat  variable.  It  belongs  to  the  internal 
oontact  class  of  insecticides,  and  sells  at  about 
thirty-five  cents  per  pound. 
London  purple  is  a by-product  in  the  manufacture 
of  aniline  dyes,  placed  upon  the  market  by  the 
Hemingway  London  Purple  Co.  of  London,  England. 
Its  action  is  nearly  the  same  as  Paris  green,  and 
it  contains  nearly  the  same  amount  of  arsenic. 
London  purple  and  Paris  green  are  known  as 
the  arsenites.  They  are  used  in  a dry  form  or  they 
can  be  mixed  with  flour  to  advantage  in  many 
cases.  The  arsenites  are  practically  insoluble  in 
water,  the  particles  (remaining  suspended.  The 
proportion  generally  used  is  one  pound  arsenite  to 
200  gallons  of  water.  If  too  strong  a proportion 
is  used,  the  foliage  to  which  the  arsenites  are  applied 
will  be  scorched ; hence,  for  tender  foliage,  such 
as  the  peach,  a weaker  mixture,  say  one  pound  to 
300  gallons,  should  be  used. 
Damage  to  foliage,  however,  can  be  almost  entirely 
prevented  by  mixing  a little  lime  water  with  the 
arsenical  mixture.  We  owe  this  discovery  to  Prof. 
C.  P.  Gillette,  of  Colorado,  formerly  of  the  Iowa 
Experiment  Station.  If  lime  water  be  added  to  the 
mixture  the  arsenites  can  be  safely  applied  to  the 
most  tender  foliage,  when  used  in  the  ordinary 
proportion  of  one  pound  arsenite  to  200  gallons  of 
water. 
The  arsenites  aie  used  to  destroy  any  of  the 
mandibulate  insects,  and  kill  by  being  taken  into 
the  alimentary  system.  Eleven  years  ago  they 
were  first  brought  forward  as  a remedy  for  the  well- 
known  coddling  moth.  Spraying  with  the  arsenites 
for  this  pest  is  now  practiced  by  all  the  more  pro- 
gressive farmers  of  the  Middle  and  Eastern  States, 
and  any  fruit  growers  who  do  not  practice  it  are 
annually  losing  a large  percent,  of  their  crop  through 
a neglect  of  this  simple  operation. 
Kerosene  emulsion  is  the  best  insecticide  of  the 
external  class.  Kerosene  itself  cannot  be  used  upon 
plants  infested  with  inseots  aa  it  would  kill  the  foli- 
age, hence  it  must  be  diluted  if  it  is  to  be  used  as 
an  insecticide.  The  idea  of  diluting  the  kerosene 
with  soap  suds  probably  originated  with  Mr.  Henry 
Bird,  of  Newark,  N.  J.,  in  1875,  and  two  or  three 
years  later  an  emulsion  was  made  by  Prof.  A.  J. 
Cook,  of  the  Michigan  Agricultural  College,  and 
Dr.  C.  V.  Riley,  Entomologist  of  the  United  States 
Department  of  Agriculture.  It  was  first  practically 
used  and  recognized  as  a valuable  insecticide  by  Mr. 
H.  G.  Hubbard  while  conducting  some  experiments 
upon  scale  insects  in  Florida  under  the  auspices  of 
the  Department  of  Agriculture.  During  the  last 
three  years  the  kerosene  emulsion  has  come  into 
general  use. 
There  are  two  formulae  for  making  the  kerosene 
emulsion  now  in  use.  The  one  is  known  as  the 
Hubbard-Riley  formula  and  the  other  as  the  Cook 
formula,  the  difference  between  them  being  that  the 
former  contains  eight  times  more  kerosene  to  the 
same  amount  of  soap  and  water  than  does  the 
latter  formula. 
The  Hubbard-Riley  formula  is  made  as  follows : 
kerosene,  two  gallons ; hard  soap,  one-half  pound ; 
hot  water,  one  gallon.  The  soap  is  dissolved  in 
the  hot  water ; and,  while  still  hot,  should  be 
poured  into  the  kerosene  and  thoroughly  mixed  by 
pumping  through  a force  pump,  when  the  soap 
suds  will  unite  with  the  kerosene,  forming  a thick, 
creamy  emulsion.  The  emulsion  thus  formed  can 
be  put  away  in  bottles  for  use  at  a future  time,  or 
can  be  used  at  once.  When  used  it  should  be 
diluted  with  about  nine  times  its  bulk  of  water. 
The  Cook  emulsion  is  made  in  a similar  way 
according  to  the  following  formula : kerosene,  one 
quart;  hard  soap,  one-half  pound;  hot  water,  one 
gallon.  The  soap  is  dissolved  in  the  hot  water, 
and  the  kerosene  mixed  with  it  as  before.  When 
ready  for  use  it  is  diluted  with  two  or  three  times 
its  bulk  of  water. 
A good  emulsion  is  one  in  which  the  kerosene 
will  not  separate ; and  either  of  the  above,  if  made 
properly,  will  be  found  excellent  for  use  against  any 
insect,  where  we  wish  to  kill  by  external  contact. 
Bisulphide  of  carbon  is  an  excellent  insecticide 
for  some  purposes.  By  meins  of  volatile  fumes  of 
this  substance  we  can  reach  many  insects,  which 
cannot  be  well  destroyed  in  any  other  way.  It  is 
especially  useful  in  destroying  ants  and  grain  inseots. 
To  destroy  an  ant-hill,  by  means  of  a crowbar  or 
stick,  a hole  is  made  in  the  center  of  the  hill,  into 
which  a small  amount  of  the  bisulphide  is  poured. 
The  hill  is  now  covered  with  a wet  blanket,  to 
allow  the  fumes  to  penetrate  all  parts  for  a few 
minutes,  when  the  blanket  is  removed  and  a match 
applied.  The  fumes  are  explosive,  and  the  odor  will 
effectually  destroy  all  ants  within  the  hill. 
For  grain  insects  the  bisulphide  is  used  to  destroy 
various  weevils  and  moths  fouud  within  stored  grain. 
This  is  done  by  putting  the  grain  into  a bin  as  tight 
as  possible,  in  order  that  the  fumes  may  not  escape. 
In  such  a bin  the  bisulphide  is  put  into  an  open 
dish  on  top  of  the  grain,  and  allowed  to  evaporate. 
As  the  fumes  are  heavier  than  air  they  will  peue- 
trate  to  the  bottom  of  the  bin 
There  are  many  other  insecticides  of  greater  or 
less  importance,  among  which  should  be  mentioned 
whale-oil  soap  and  carbolic  acid,  both  of  which 
make  an  excellent  wash  for  trunks  of  apple  trees, 
to  prevent  borers.— Cor.  K.  F.  Independent. 
Agricultural  College.  Miss. 
NOTES  ON  PRODUCE  AND  FINANCE. 
The  Wood  Used  for  Tea  Packages. — The  follow- 
ing letter  has  been  addressed  by  thi  hou.  seoretary  of 
the  London  Wholesale  Tea  Dea  ers’  Association  to 
Mr,  Ernest  Tye,  secretary  of  the  Iudiau  Tea  Districts 
Association  : — ‘ The  attention  of  my  commit  ee  has 
been  drawn  to  the  objectionable  flavour  in  some  cases 
i uparted  to  Indian  teis  by  tli6  wood  used  for  the 
package",  and  I am  informed  that  in  particular  gar- 
dens saw  mills  are  fiequen'ly  part  of  the  plaut,  and 
when  the  wood  used  is  too  green,  the  juices  produoe  ijj' 
