292 
JOURNAL  OF  HORTICULTURE  AND  COTTAGE  GARDENER. 
September  23,  1897. 
APPLE  TREE  TWIG  AND  BRANCH, 
AND  SOME  THINGS  ON  THEM. 
The  specimens  sent  some  time  ago  for  examination  and  report,  in 
reply  to  the  query  of  ‘‘  F.  C.” — namely,  “  AVhat  is  the  matter  with 
the  enclosed  Apple  tree  twigs  and  branch  ?  ”  are  so  characteristic  of  the 
condition  to  which  the  British  Apple  tree  may  be  reduced  by  the  attacks 
of  two  of  its  most  inveterate  enemies,  that  portrayal  of  them  cannot  be 
otherwise  than  useful. 
The  twig  (tig.  42.  A)  had  been  cut  off  by  a  knife  at  a  point  where 
the  wood  and  bark  were  quite  clean  and  healthy,  and  consisted  of  one 
to  four-year-old  growth,  indicated  by  the  figures  1-4.  At  the  parts  a 
mussel  scale  was  securely  fixed  ;  at  h  some  scale  had  been  removed, 
imparting  a  mottled  appearance,  and  the  wood  there  had  become  more 
or  less  swollen,  with  the  bark  wrinkled  and  cracked.  The  only  living 
buds  were  those  marked  c,  numerous  s])urs  (d)  having  died. 
On  removing  some  of  the  mussel  scale  {B)  there  fell  out  fine  dust¬ 
like  jiarticles  (c),  just  visible  to  the  unaided  eye,  some  white  eggs,  and 
black  dross.  As  there 
was  nothing  more  dis¬ 
cernible  on  the  twig,  ex¬ 
cept  a  minute  pale  pink 
speck  in  a  crack  (which 
will  be  referred  to),  I 
cut  off  a  small  slice  of 
bark  (C),  and  on  examin¬ 
ing  it  with  a  lens  enlarging 
six  diameters,  was  struck 
by  the  small  size  of  the 
scale  ;  they  were  not 
larger  than  one-third  the 
normal  size  of  those  on 
vigorous  Apple  trees, 
which  may  be  due  to 
poverty  of  food. 
Turning  over  a  scale 
(Z))  some  eggs(  f)  fell  out. 
Looking  at  the  upturned 
scale  with  a  lens  magni¬ 
fying  20  diameters,  it 
appeared  as  shown  at  E, 
the  lily  white  eggs  (g)  ^ 
being  very  conspicuous. 
They  were  noticed  to 
vary  greatly  in  form, 
therefore  I  placed  three 
(F)on  a  glass  slide,  and 
looked  at  them  through 
a  lens  enlarging  150  dia¬ 
meters.  Their  size  was 
especially  noticeable, 
being  at  least  two-thirds 
less  than  normal  ones. 
They  appeared  white 
(without  light  thrown  on 
them  by  the  reflector 
from  below),  and  had 
each  a  bright  luminous 
spot  (Ji).  Turning  on  the 
light  the  eggs  were  seen 
to  be  opaque  (*),  with  a 
thick  outside  shell  ()) 
and  yolk  (/e)  inside,  the 
Fig.  42. — Apple  Teee  Tavig  Infested 
BY  Mussel  Scale. 
nucleus  (1)  appearing  very  References  :—A,  twig,  showing :  year’s  growths 
distinctly  and  evidently  1-4;  «,  fixed  scale;  5,  place  whfere  scale 
working.  That  was  all  removed;  c,  living  buds;  dead  spurs. 
°  B,  matured  scale ;  e,  dust-like  contents.  C, 
there  was  to  be  seen  as 
regards  the  scale  at  the 
time,  but  sufficient  for 
identification,  namely :  — 
Alussel  Scale.  Mytilapsis 
pomorum,  Bouche. 
It  is  hatched  from  the 
eggs  about  the  middle  of 
May,  sometimes  earlier, 
and  at  others  later,  accord¬ 
ing  to  season,  the  egg 
usually  assuming  a  wood¬ 
louse-like  form  before  the 
small  slice  of  bark  with  scale  enlarged 
4  diameters.  B,  under  side  of  a  scale;  f, 
eggs  (enlarged  4  diameters).  E,  the  same 
magnified  20  times ;  g,  eggs.  F,  eggs 
(enlarged  100  times),  showing;  h,  luminous 
spot;  i,  opaque  (as  seen  illumined)— y,  out¬ 
side  shell ;  k,  yolk ;  7,  nucleus  =  Mytilapsis 
pomorum  in  embryo.  G,  form  of  egg  before 
insect  emerges.  H,  larva.  J,  female  or 
scale  “fixed.”  J,  pupa  form  of  insect.  K, 
hard  brown  shell  =  scale.  L,  male  =  Myti¬ 
lapsis  pomorum — female  J.  {G — L  magnified, 
natural  size  on  side.) 
larva  emerges,  as  shoAvn 
at  G.  The  larva  {IT)  is  white  at  first,  becoming  yellowish  or  grey, 
as  also  do  the  eggs  before  hatching,  and  it  has  six  legs,  jointed 
antennae,  side  bristles,  and  caudal  hairs  -an  elongated,  woodlouse¬ 
like  creature.  The  larvae,  which,  escaping  the  attention  of  carnivorous 
insects  and  birds,  soon  settle  down,  always  on  living  bark  where  the 
sap  flows  by  to  buds  or  fruits,  and  push  their  beaks  into  the  tissues 
of  the  bark,  causing  the  tree  to  strive  repair  the  injury  done  by 
growth  of  cellular  tissue,  and  the  tAvig  below  may  become  swollen 
more  or  less,  whilst  where  the  insects  are  it  gets  smaller.  Some¬ 
times  the  larvae  fix  on  the  footstalks  of  the  fruit,  especially  on  Fears, 
and  even  on  the  fruit  itself,  and  it  means  diminution  of  the  supplies 
of  nutriment  to  the  immediate  jiarts  and  those  above,  hence  resulting 
in  depression. 
The  creature  that  fixes  itself  is  the  female  (f),  which  turns  to  pupa, 
and  commences  to  form  a  scale,  fastening  it  with  threads  to  the  bark, 
with  openings  between,  so  that  breathing  is  not  interfered  with.  If  we 
turn  up  one  of  such  soft  scale  (J)  it  is  seen  the  insect  has  dispensed  with 
the  legs  and  other  appurtenances,  retaining  only  three  pairs  of  bristles 
on  the  hinder  part  of  the  body,  and  has  developed  an  enormous  beak 
(when  magnified),  just  the  right  length  to  reach  the  sap  ;  also  note  the 
body  is  plainly  segmented.  Still  it  grows  that  is  the  scale,  and  at  last 
becomes  a  hard  broAvn  shell  (A'),  more  or  less  curved  and  wrinkled  across. 
The  female  produces  ova  or  eggs,  going  on  until  there  is  not  a  particle 
of  her  body  left  but  the  head,  then  it  is  all  over  for  that  year  or  cycle, 
and  there  is  nothing  beneath  the  scale  but  eggs,  a  little  Avhito  cottony 
matter,  and  some  dirt. 
Of  course  we  have  not  as  yet  seen  a  Mytilapsis  pomorum,  only  a  hevy 
of  eggs,  larv»,  and  perfect  female.  At  L  is  the  “  lord  ”  of  the  mussel 
scale  family.  Like  to  see  one  .^  Then  get  some  strijis  of  bright  tin  plate, 
about  3  inches  wide  and  a  foot  long,  jiaint  both  sides  with  a  smear 
formed  of  sAveet  oil  and  resin,  melted,  putting  on  Avith  a  brush  lightly,  and 
it  then  shines  like  gold  and  silver,  placing  in  the  forks  of  the  Apple  tree, 
Avhen,  or  soon  after,  the  females  fix  themselves.  Look  carefully  Avith  a 
magnifying  glass,  and  amid  the  host  of  captured  creatures  may  be  found 
the  exact  model  of  the  insect  shown  at  L.  Ferha])S  it  may  be  the  first 
time,  or  probably  not  for  years,  for  male  scale  insects  are  about  as 
difficult  to  catch  as  the  females  are  the  reverse. 
“F.  ^V.  C.”  wishes  to  kpow  Avhat  he  can  do  in  his  case  as  preventive 
and  remedial.  The  case  is  such  a  complicated  one,  as  Ave  shall  shoAv 
presently,  that  it  is  difficult  to  confine  our  remarks  to  the  mussel  scale, 
birt  as  there  are  instances  Avhere  there  is  it  Avithout  the  other  things,  AA'e 
may  dispose  of  the  scale  first,  and  menlion  for  avoidance  the  scraping  of 
the  bark  Avith  any  kind  of  implement,  for  it  is  a  bad  old  jiractice.  Never¬ 
theless,  some  ancient  plans  are  good,  one  of  the  best  the  potash  and  soda 
solution  of  old-fashioned  gardeners  taken  by  Britain’s  sons  and  daughters 
to  the  ends  of  the  earth,  and  given  back  to  us  in  stronger  and  better  acting 
form.  I  allude  to  Mr.  Leonard  Coates’  solution  of  caustic  soda  and  com¬ 
mercial  potash,  first  propounded  by  him  in  the  Journal  of  Horticulture. 
The  old  method  Avas  to  place  Avood  ashes  in  a  Avooden  vessel  and 
pour  on  enough  rain  water  to  cover  them,  alloAving  to  steep  two  or 
three  days  and  then  strain  off  the  clear  liquid — potash  lye.  Measure 
the  lye,  and  in  another  vessel  place  in  as  manj'  ounces  of  washing 
soda  as  ([uarts  of  liquor  measured,  and  pour  on  as  much  boiling  Avuter 
as  the  measure  of  potash  lye,  and  Avhen  dissolved  pour  into  the  vessel 
containing  the  last  named.  While  AAarm  apply  Avith  a  scrubbing  brush 
to  all  affected  parts  of  the  tree,  and  with  a  half  worn  paint-brush  to 
the  spurs,  applying  thoroughly  on  a  fine  day  Avhile  the  trees  are  quite 
dormant. 
Mr.  Leonard  Coates’  solution  has  the  advantage  of  being  stronger, 
and  can  be  sprayed  on,  therefore  the  Avork  is  more  expeditiously 
performed.  The  formula  is  ; — Half  a  pound  each  of  caustic  soda,  98  per 
cent,  purity,  and  commercial  potash  — carbonate  of  potash  or  pearlash. 
Dissolve  the  articles  in  a  small  quantity  of  water  separately,  add  together 
when  dissolved,  and  dilute  with  hot  water  to  5  gallons,  applying  at  a 
temperature  of  130°  by  means  of  a  spraying  apparatus,  Avetting  every 
part  of  the  tree  on  a  fine  day,  or  when  dry  and  not  frozen,  the  buds  being 
quite  dormant.  The  best  time,  however,  for  killing  scale  is  when  they 
are  in  the  larval  state,  soon  after  they  have  hatched,  spraying  with 
soluble  petroleum  or  any  approved  insecticide  about  the  middle  of  May, 
and  at  intervals  of  ten  days  to  the  middle  of  June.  The  scale  are  then 
as  easily  killed  as  aphides  ;  but  when  they  get  fixed,  resin  AAushes  are 
most  effective  on  soft  scale,  forming  an  impervious  coating  over  the 
insects  and  smothering  them.  If  nothing  be  done  in  summer  time,  then 
there  is  the  above-mentioned  solution,  also  the  old-fashioned  never- 
failing  dressing  of  boiled  linseed  oil,  applied  with  a  brush  as  soon  as  the 
trees  are  leafless.  I  have  tried  raw  petroleum,  and  not  found  it  clear 
some  badly  infested  Pear  trees  on  a  Avail,  probably  because  it  did  not  get 
under  the  scale  and  reach  the  eggs.  It  does  not  smother  them  like  the 
oil,  or  dry  them  up  like  something  caustic. 
Now  we  will  return  to  the  living  twig,  A  (fig.  42).  Remember,  it  is 
alive,  or  scale  would  not  be  there,  or  the  wood  green,  with  buds  at  its 
extremities.  Let  there  be  no  mistake  about  this  matter,  for  it  is  the  crux 
of  the  subject,  and  has  reference  only  to  a  little  pink  speck  in  a  crack  of 
the  bark  ;  yet  a  very  old  acquaintance,  and  of  disastrous  consequences  to 
Apple  trees  and  many  other  species  of  Avidely  different  genera.  For 
clearness,  it  is  shown  on  a  spur  (where  it  occurs),  M  (fig.  43),  enlarged 
four  diameters.  There  are  plenty  of  mussel  scale  insects  {in'),  and 
these  may  easily  be  mistaken  as  the  cause  of  the  swelling  (n).  They 
certainly  have  made  minute  holes  in  the  bark  by  their  beaks,  and 
something  else  has  got  through  one  of  such  openings,  and  this  was 
the  cause  of  the  spurs  dying.  This  I  satisfied  myself  about  by 
removing  a  slice  of  bark,  and  there,  betAveen  the  bark  and  wood,  was 
fungal  hyphae. 
We  come  to  the  crack  (o),  and  a  pale  jiink  speck  in  it  shoAvn 
Avhite  (p).  Removing  that  it  appeared  the  size  shown  at  N,  and  Avhen 
magnified  six  diameters  as  at  0,  while  at  P  it  is  represented  twenty  times 
and  at  Q  67  times  larger  than  as  seen  by  the  unaided  eye.  It  was 
noticed  as  a  young  fungal  plant  not  fully  developed,  but  sufficiently  so 
for  identification,  the  head  having  a  paler  stem  spreading  upwards  into 
a  somewhat  globose  crown,  and  Avhen  full-bloAvn  (A,  enlarged  twenty 
diameters),  covered  with  a  delicate  mealy  bloom.  The  body,  at  its  base, 
penetrates  to  the  inner  bark,  whence  the  mycelial  threads  spread  in  aU 
directions,  confined,  however,  to  the  cortical  tissues,  and  not  entering  the 
