May  I,  1897.] 
THE  TROPICAL 
AGRICULTURIST. 
739 
Agricultural  Pests : 
WITH  METHODS  OF  PREVENTION. 
BY  MISS  E.  A.  ORMEROD, 
(Late  Consulting  Entomologist  to  the 
Royal  Agricultukal  Society  of 
England). 
IV. 
Injcrious  Moths — Methods  or  Prevention. 
In  the  case  of  the  white  cabbage  butterflies,  the 
caterpillars  of  which  often  do  serious  mischief  in 
gardens,  they  have  been  found  not  to  do  so  much 
harm  in  proportion  to  field  cabbage,  because  the 
caterpillars  choose  a dry,  well-sheltered  place  to  change 
in.  For  this  they  crawl  away  from  their  food-plants, 
and  hang  themselves  by  a silken  band  under  eaves, 
palings,  or  the  like  shelter,  out  of  doors,  or  in  any 
neglected  corners  in  garden-sheds,  where  they  ai’e 
allowed  accommodation,  and  much  may  be  done  to 
lessen  amount  of  attack  simply  by  tidiness.  The 
collections  of  old  brooms,  bits  of  wood,  and  dry  rubbish 
of  every  kind  in  which  they  shelter,  are  much  better 
away,  whether  indoors  or  out ; and  a brnsh  taken 
along  angles  and  in  corners  and  under  stairs,  ladders, 
beams,  &c.,  in  garden-sheds,  will  sometimes  clear  the 
chrysalids  out  by  the  handful.  A search  of  this  kind 
between  the  time  of  the  first  and  second  brood  in 
summer,  and  some  time  between  November  and  March, 
would  do  much  good. 
It  is  an  excellent  principle  to  keep  down  the  effect 
of  in.sect-attack  by  broad  measures  of  agricultural 
treatment  which  will  carry  the  plant  well  on  away 
from  the  power  of  the  insect ; but  at  the  same  time 
it  should  not  be  forgotten  that  when  there  are  a 
great  number  of  large  caterpillars  or  chrysalids  plainly 
to  be  seen,  and  easily  to  be  laid  hold  of — ^^ether 
with  fingers  or  by  other  means — ^the  best  thing  to  do 
is,  forthwith,  to  lay  hold  of  them. 
There  are  not  many  kinds  of  butterfly  caterpillars 
which  are  hurtful  to  crops  in  England ; but  amongst 
the  hosts  of  difierent  kinds  of  moth  caterpillars  that 
cause  great  loss,  about  the  very  largest  of  all,  which 
is  that  of  the  death’s  head  moth,  is  best  got  rid  of 
by  hand-picking.  This  sometimes  does  much  harm 
to  potatoes  by  feeding  on  the  leafage. 
The  caterpillar  usually  hides  by  day,  and  feeds 
in  the  'evening  or  at  night ; therefore,  when  great 
harm  is  found  to  be  going  on  (either  iu  this  case 
or  others  like  it)  from  an  unseen  enemy,  it  is  well 
for  some  trustworthy  person  to  watch  at  dusk  or  dawn 
for  what  is  going  forward,  and  with  large  creatures 
like  these  caterpillars  a very  small  quantity  of  light 
will  be  enough  to  see  them  by  as  they  gentley  move 
the  leafage  in  feeding.  When  full-fed  the  caterpillar 
goes  down  into  the  ground  to  change;  therefore, 
turning  up  the  chrysalids  is  an  easy  measure  of 
prevention  with  this  potato-feeder. 
The  vaiious  kinds  of  attacks  of  moth  caterpillars 
are  so  many,  and  the  injuries  they  cause  so  great, 
that  in  whatever  point  we  may  select  now  for  study, 
it  seems  at  the  cost  of  leaving  out  something  else 
of  importance;  but  in  these  short  details.  I have  tried 
to  draw  attention  to  some  four  or  five  principles 
of  preventing  or  remedying  attack : — 
One  is  taking  away  shelter  (as  in  the  case  of 
cabbage  caterpillars).  Another,  the  possibility  of 
hand-picking,  shaking  down,  gathering,  or  whatever 
term  we  use  for  it,  being  so  managed  as  to  be  a 
practicable  and  paying  operation,  instead  of  a ridiculous 
loss  of  time.  Another  is  prevention  of  egg-laying 
on  fruit  bushes,  by  keeping  them  so  properly  pru- 
ned that  there  is  no  attraction  of  cracks  and  crevices. 
We  have  also  noticed  that  the  caterpillars  may  be 
smoked  or  poisoned  in  their  burrows — a simple  piece 
of  knowledge,  but  yet  one  which,  some  few  years  ago, 
would  have  been  of  great  service  in  saving  coffee 
shrubs  in  one  of  our  colonies.  Further,  we  have 
noticed  that,  with  webbing  caterpillars,  it  is  dicidedly 
well,  before  we  pay  our  visit,  to  see  if  the  family 
are  at  bouie. 
With  the  great  increase  of  the  fruit  industry,  we 
have  now  areas  of  thousands  of  trees  where  for- 
merly these  were  counted  by  hundreds,  and  we  have 
a consequent  increase  in  amount  of  the  attendant 
fruit-tree  insect  vermin.  Where  there  is  a large 
extent  of  plant  growth  of  any  kind,  orchard  trees 
or  otherwise,  affording  food  in  their  feeding  condition, 
and  shelter  in  their  other  stages,  to  special  kinds 
of  insects  all  the  year  round,  and  for  successive  years, 
there  these  insects  are  sure  to  be  present.  This  has 
been  the  case  in  such  a marked  and  increased  degree 
during  the  past  few  years,  and  in  some  of  our  fruit- 
growing localities,  as  to  necessitate  the  adoption  of 
some  special  measures  of  prevention  suitable  to  the 
special  habits  of  some  of  the  kinds  of  caterpillars, 
and  also  of  remedial  applications  suitable  for  sweeping 
them  all  off  and  destroying  them  together  (whatever 
their  other  habits  may  be),  when  broadscale  ravage 
on  the  leafage  calls  for  broadscale  clearance. 
One  very  important  division  of  caterpillars  to  which 
measures  of  prevention  can  be  applied,  is  that  of 
the“looper”  caterpillars  of  various  kinds  of  moths, 
of  which  the  females  are  either  totally  wingless,  or 
the  wings  are  abortive  to  such  a degree  as  to  prevent 
them  being  of  service  in  flying.  Of  these,  two  of  the 
most  hurtful  kinds  are  the  mottled  umber  ( Hyhernia 
defolianaj,  and  the  too  well-known  winter  moth, 
sometimes  called  the  Evesham  moth. 
The  method  of  life  of  both  the  above  kinds  is  for 
the  caterpillar  to  hatch  in  the  spring,  on  the  orchard 
trees  on  which  the  eggs  have  been  laid,  and  feed 
on,  or  possibly  fairly  ravage,  the  leafage  and  all  the 
soft  growths,  during  a period  which  may  be  from 
about  the  end  of  March  until  the  end  of  .June.  Then 
the  caterpillars  leave  the  trees,  and  go  through  the 
change  to  chrysalis  state  beneath  them.  This  may 
be  just  about  the  surface  of  the  ground,  or  a little 
below.  From  these  the  moths  begin  to  come  out  in 
October  or  November,  and  the  wingless  female  moths 
creep  up  the  trees  and  deposit  their  eggs.  This  habit, 
if  the  moths  only  went  up  the  trees  during  a special 
geriod,  would  put  means  of  prevention  at  once  in  our 
ands.  But  even  as  it  is,  the  infestation  may  be 
greatly  reduced  by  putting  bands  of  sticky  material 
round  the  trunks,  such  as  will  either  deter  the  moths 
from  trying  to  go  up,  or  hold  them  firm  if  they  try 
to  cross.  This  plan  catches  the  moths  by  hundreds 
on  each  tree,  but  care  must  be  taken  lest  the  mixture 
applied  should  injure  the  bark.  On  the  rugged,  thick 
bark  of  old  trees,  where  the  out-side  is  a mere  dry 
dead  coating,  it  is  possible  that  even  tar  may  be 
applied  without  doing  harm,  though  not  without  risk. 
But  with  young  trees  there  is  veiy  great  danger 
of  serious  injury,  and  sometimes  great  losses  have 
taken  place  consequent  on  tar  or  grease  being  applied 
direct  to  the  bark.  The  application  soaks  into  the 
tissues,  and  the  tree  in  such  case  perishes. 
The  safest  way  is  to  begin  by  passing  a band  of 
tough  grease-proof  paper,  such  as  may  be  procured 
at  very  small  co  t from  grocers,  round  the  tree.  This 
may  be  about  seven  inches  wide,  but  the  wider  the 
better;  the  ends  should  overlap,  and  the  paper  be 
secured  in  its  place  by  a piece  of  string  being  tied 
round  near  the  upper  and  lower  edges.  On  this  the 
grease  may  be  smeared,  A flat  bit  of  wood,  like  a 
paper-knife,  is  a convenient  implement  for  spreading 
it  with,  and  common  cart-grease  answers  well  as  a 
cheap  and  effective  application.  Even,  however,  where 
the  tree  is  protected,  some  care  must  be  exercised 
in  the  choice  of  the  “ sticky  ” mixture  selected  as 
some  of  the  materials  sold  under  the  name  of  “ axle- 
grease”  contain  petroleum  residue,  animal  grease,  or 
other  components,  which,  like  tar,  would  have  very 
undesirable  effects  if  (as  I have  myself  seen  to  happen) 
they  should  soak  through  the  suppo.ied  grease-proof 
paper  to  the  bark, 
The  above  treat)uent  does  much  good,  but  does 
not  answer  perfectly,  for  ^ he  following  reason.  Though 
the  great  body  of  these  moths  come  out  from  the 
middle  of  October  to  December,  this  period  by  no 
means  includes  the  whole  appearance.  We  find  them 
still  at  the  end  of  January,  and  the  later  brood  may 
be  found  coming  up  towards  the  end  of  winter- 
and  at  the  end  of  March  another  kind  of  moth,  witli 
wingless  females,  namely,  the  Anisoptenjx  cescularia, 
