156 
JOURNAL  OF  HORTICULTURE  AND  COTTAGE  GARDENER. 
August  15,  1901. 
Tent  Caterpillars. 
Two  species  of  so-called  “  tent  caterpillars  ”  are  frequently  found 
on  various  fruit  trees,  especially  on  the  Apple,  Plum,  and  Pear.  By 
far  the  commonest  and  most  destructive  is  the  lackey  moth  caterpillar 
(Clisiocampa  Neustria).  But  in  parts  of  England,  notably  districts  in 
Kent,  the  somewhat  local  brown-tail  moth  (Porthesia  cbrysorrbcea) 
does  almost  as  much  harm  in  some  seasons ;  this  especially  applies  to 
the  present  year,  the  caterpillars  having  done  considerable  damage  to 
Apple  and  Plum  orchards  in  parts  of  Kent.  These  two  insects  are  called 
“tent  caterpillars”  on  account  of  the  larvae  forming  tent-like  nests  of 
silk  on  the  trees,  in  which  they  live  during  their  early  existence,  and 
beneath  which  they  shelter  during  wet  weather,  and  at  night  when 
they  are  more  mature.  The  damage  caused  by  these  two  larvae  can 
easily  be  prevented,  and  even  when  they  have  a  considerable  hold  on 
the  orchard  they  can  be  remedied  to  some  extent  by  spraying.  Tent 
caterpillars  also  occur  in  great  numbers  in  America  ;  there,  as  here, 
being  very  ravenous  feeders,  they  soon  strip  the  foliage  off  the  trees, 
and  cause  the  fruitlets  to  fall.  As  there  is  some  difference  in  life  history 
as  well  as  in  appearance  between  the  two  species,  they  are  best 
considered  separately  as  far  as  their  natural  history  goes  ;  prevention 
and  treatment  are  the  same  for  both  species. 
The  Lackey  Moth. 
The  lackey  moth  (C.  Neustria)  is  widely  distributed  over  the 
south,  west,  and  middle  of  England,  but  is  by  far  more  abundant  and 
destructive  in  the  south  and  west  than  in  other  parts.  It  does  not 
occur  further  north  than  York,  where  it  is  usually  rare.  Always 
more  or  less  prevalent  in  the  south,  at  certain  times  it  occurs  in 
greater  abundance,  and  Apple  and  Pear  orchards  are  sometimes 
stripped  of  every  vestige  of  foliage  by  the  caterpillars.  It  is  more 
abundant  in  France  than  elsewhere  ;  there  being  laws  compelling 
growers  to  cut  off  and  destroy  the  “  tents  ”  formed  by  the  larvae. 
Guerin  Meneville  states  that  it  is  one  of  the  most  injurious  fruit  and 
forest  pests  in  France.  Kollar  gives  an  account  of  it,  and  says  that 
it  is  troublesome  in  Germany. 
The  moth  is  very  variable  in  colour  and  size,  and  measures  about 
an  inch  in  expanse  of  wings  in  the  male,  and  1£  inch  ’n  the  female. 
The  fore  wings  are  a  rusty  reddish-brown,  yellowish-brown,  orchreous 
or  brick-dust  red,  with  two  pale  or  dusky  brown  transverse  lines 
across  them,  the  space  between  the  two  bars  being  often  more  deeply 
coloured  than  the  rest  of  the  wing;  the  hind  wings  are  the  same  tint 
as  the  lore,  but  often  a  little  paler ;  the  thorax  and  abdomen  are 
densely  scaly.  The  adult  may  be  taken  on  the  wing  at  dusk  in  July 
and  August,  and  even  as  late  as  September.  The  eggs  are  deposited 
by  the  female  in  rings  on  the  smaller  shoots  of  the  fruit  trees,  each 
band  containing  from  forty  to  over  200  eggs.  These  bands  remain 
on  the  trees  all  the  winter.  When  the  wood  shrinks  they  can  be 
turned  round  and  round  with  ease.  Bting  greyish-brown  in  colour 
the  ova  are  readily  seen  on  the  dark  ground  colour  of  the  twigs,  and 
are  thus  well-known  objects  in  an  orchard. 
About  the  end  of  April  they  hatch.  The  young  larvae  are  almost 
black  at  first,  and  more  or  less  hairy.  Yery  soon  after  they  commence 
to  form  a  fine  web,  enclosing  a  few  leaves,  and  beneath  this  little  tent 
of  silk  they  continue  to  feed  for  some  time.  As  they  grow  the  silken 
house  is  enlarged,  until  in  some  large  colonies  it  may  reach  nearly  a 
foot  in  length.  At  first  the  larvse  feed  entirely  under  the  tent,  but 
as  they  grow  they  spread  out  over  the  trees,  and  feed  off  the  leafage 
and  blossom,  returning  to  the  web  at  night  and  in  wet  weather.  They 
become  brilliantly  coloured  as  they  grow,  being  bluish-grey,  with  two 
black  spots  on  the  segment  next  the  head,  and  two  also  on  the  bluish- 
grey  head  ;  three  orange-red  stripes  along  each  side,  and  between  the 
two  lowest  of  these  is  a  broad  blue  stripe  with  little  black  specks, 
these  brilliant  lines  being  separated  by  black  and  black  spotted  with 
blue,  and  a  white  stripe  down  the  back  with  a  narrow  Hack  line  on 
each  Bide  ;  the  whole  larva  is  covered  with  rather  rusty  hairs,  darker 
above  than  at  the  sides.  When  full  grown  it  reaches  1^  inch  in 
length.  On  warm  days  they  may  ofttn  be  found  in  batches,  several 
lying  parallel  with  one  another,  either  on  the  outside  of  the  tent  or 
along  the  branches.  They  are  somewhat  timid,  and  fall  to  the 
ground  on  the  tree  being  shaken,  but  soon  crawl  back  to  the  foliage 
again.  They  are  sometimes  said  to  lower  themselves  by  a  silken 
thread,  but  this  is  not  certain. 
From  the  middle  of  June  to  the  end  of  July  they  reach  maturity, 
and  spin  a  delicate  loose  white  cocoon,  the  silk  mixed  with  a  yellowish 
powder  and  numerous  hairs  of  the  larvae.  These  cases  are  formed 
amongst  the  leaves,  on  the  bark,  amongst  grass  below  the  trees,  on  walls, 
fences,  &c. ;  always  above  ground.  In  this  cocoon  the  larva  changes 
to  a  dark-brown  pupa,  from  which  the  moth  hatches  out  in  from  two 
to  three  weeks.  The  “lackey”  larvae  feed  also  on  Oak,  Hawthorn, 
and  many  o'her  trees  and  shrubs. 
The  Brown-tail  Moth. 
According  to  Stainton  the  brown-tail  moth  (Porthesia  chrysorrhcei)- 
is  local,  and  not  to  be  found  every  whet  e.  Where  it  does  occur, 
however,  it  is  often  very  abundant.  It  is  recorded  from  Lytham, 
Epping,  Teignmouth,  Lewes,  Lymington,  Tenterden,  Ramsgate, 
Stowmarket,  Black  Park,  Chesham,  Deal,  Dorking,  Newhaven, 
Bisterne,  Bristol,  Norwich,  Canterbury,  and  many  other  places.  It  has 
been  very  abundant  this  year  in  Kent,  and  has  done  quite  as  much  if  not 
more  harm  in  the  orchards  than  the  lackey  moth.  It  is  always  more 
or  less  abundant  in  various  parts  of  the  country.  The  moth  appears 
towards  the  end  of  July  and  in  Augu-t.  The  female  has  pure  white 
fore  wings,  with  a  faint  black  spot ;  hind  wings  pure  white. 
The  male  has  similar  fore  and  hind  wings,  white  head,  thorax  and 
abdomen,  the  apex  of  the  latter  having  a  golden  brown  tuft.  In  length 
the  wing  expanse  varies  between  inch  and  If  inch.  It  is  a  night 
flyer,  resting  during  the  day  on  walls,  leaves,  lamps,  &«.,  and  is  then 
very  sluggish,  falling  down  as  if  dead  when  its  resting  place  is 
shaken.  The  female  lays  her  eggs  on  the  under  surface  of  the  leaves 
of  the  Oak,  Elm,  Black  and  White  Thorn,  Apple,  Plum,  and  some¬ 
times  Pear.  Each  patch  of  eggs  is  covered  over  by  hair  from  the  female’s 
tail,  and  completely  hidden  ;  the  eggs  are  round,  of  a  golden  hue,  and 
as  many  as  250  may  be  counted  in  each  batch. 
The  larvae  hatch  out  about  the  beginning  of  August,  and  live 
through  the  winter.  At  first  they  are  very  small,  of  a  dirty  yellow 
appearance,  with  a  black  head,  and  four  rows  of  black  dots  and 
numerous  hairs.  They  at  once  spin  a  single  leaf  together,  eating  only 
the  epidermis,  and  attaching  the  leaf  by  silk  to  the  twig  so  that  it 
cannot  fall  off.  Towards  September  they  commence  to  make  a  regular 
tent  or  nest,  attaching  a  number  of  leaves  together  by  si  k.  The 
leaves  are  lined  and  covered  with  silk,  and  all  firmly  united.  This 
nest  is  used  as  a  place  of  protection  from  cold  and  damp,  and  as  a 
nocturnal  residence,  just  as  in  the  lackey  moth.  During  the  latter 
part  of  August  the  larvse  moult,  and  still  feed  on  as  long  as  the  leaves 
contain  any  sap.  Even  after  the  leaves  have  fallen  it  is  not  unusual 
to  see  the  larvae  on  a  sunny  warm  day  basking  in  the  sun  outside  the 
tent.  As  the  weather  becomes  cold,  they  become  dormant  and  remain 
in  their  dwelling.  The  hardest  frosts  do  not  seem  to  harm  them.  In 
the  spring  they  commence  to  feed  on  the  leaves  as  they  open,  the 
larvae  wandering  freely  over  the  trees.  Very  frequently  the  colony 
divides,  two  nests  being  made,  and  sometimes  even  a  third  is  formed. 
Early  in  May  they  moult  again  and  assume  a  deep  brown 
appearance  with  reddish-brown  hairs,  a  row  of  white  spots  on  each 
side,  a  narrow  double  broken  line  of  red  alone  on  the  dorsum,  black 
between,  and  with  two  prominent  bright  red  tubercles  on  the  back  of 
the  eleventh  and  twelfth  segments,  depressed  in  the  centre;  these 
tubercles  can  be  elevated  or  depressed  by  the  larvae  at  will.  After 
this  moult  they  spread  over  the  fruit  trees,  furs  iking  their  nests,  and 
then  devour  the  leafage  very  ravenously.  From  tl  e  end  of  June  to  the 
beginning  of  July  they  spin  a  cocoon  amongst  the  leaves  of  fruit  trees, 
as  a  rule  several  together  forming  a  large  mass  united  by  a  dusky  web. 
In  this  they  change  to  deep  brown  pujse.  Kollar  says  as  many  as  twelve 
may  be  gathered  in  one  ball ;  as  many  as  forty  has  been  counted  on  a 
Damson  tree.  From  these  pupae  the  moths  hatch  out  in  the  latter  part  of 
July  and  August,  and  soon  commence  to  lay  fresh  eggs  on  the  trees. 
Natural  Enemies. — Kollar  records  that  both  the  eggs  and  the  larvae 
of  P.  chrysorrhoea  are  attacked  by  ichneumons.  This  has  not  been 
observed  in  Britain.  Both  these  larvae  being  hairy  thev  are  avoided 
by  birds,  bo  that  little  help  is  given  by  them  in  the  orchard  where 
these  pests  are  causing  the  harm.  The  cuckoo  is  the  only  bird  known 
to  devour  these  hairy  caterpillars.  Kollar  also  mentions  two  btetles 
as  destroying  the  larvae  of  C.  Neustria  on  the  Continent — namely, 
Calosoma  sycophanta  and  C.  inquisitor. 
Prevention  and  Treatment. 
After  an  attack  of  lackey  moths  the  orchards  should  be  gone  over 
in  the  winter  and  all  egg-bands  collected  and  burnt.  Of  course  on 
large  trees  this  is  not  possible,  but  where  it  can  be  done,  it  is  a  rule 
that  should  always  be  followed.  The  small  tents  of  the  brown  tail 
should  also  be  looked  for  during  the  winter,  and  cut  off  and  burnt. 
Any  tents  left  should  also  be  collected  and  destroyed  in  the  early 
summer  either  on  a  dull  wet  day  or  of  an  evening,  that  is  when  the 
caterpillars  are  at  home,  or  no  good  would  be  done.  As  the  larvse 
readily  fall  when  shaken,  care  should  be  taken  to  hold  boards  or  a 
sheet  beneath  the  pest  when  it  is  being  cut  off,  otherwise  little  g-  od 
will  accrue,  as  the  lackeys  soon  get  back  to  the  trees. 
A  great  deal  of  damage  will  be  saved  by  spraying  as  soon  as  the 
attack  is  noticed,  especially  when  the  tents  cannot  be  reached.  For 
this  arsenical  washes  should  be  used.  Of  these  washes  the  three  best 
known  are  Paris  green,  London  purple,  and  arsenate  of  lead.  The 
latter  is  the  best  wash  of  the  three,  killing  the  larvse  and  yet  not 
damaging  the  leafage,  as  sometimes  happens  with  Paris  green. 
Paris  green  wash  is  [ repared  as  follows: — Add  £  lb.  Paris  green 
to  100  gallons  of  water,  and  mix  up  1  lb.  of  lime  well  with  the  same. 
This  must  be  kept  well  stirred.  Paris  green  can  be  used  where 
