■Supplermnl  to 
Marcli  13,  1902. 
JOUllXAL  OF  HORTICULTURE  AND 
GOTTA  GE  GARDENER. 
Fi(4.  2.  V'kktic.al  Section  of  Koaian  Hyaitnth  Infested  with 
13ac'tekio.sis. 
I>,  vertical  section  of  bulb  and  young  growth,  natural  size  :  g,  basal  part  of  bulb 
([uite  sound  bub  devoid  of  roots  ;  h,  lower  part  of  bulb  scales  free  from  disease  ; 
i,  diseased  parts  of  bulb  scales  ;  j,  diseased  spots  on  young  growth  ;  k,  growth 
of  current  year ;  1.  flower  spike  of  next  sea  on  in  embryonic  formation.  ^ 
root-mite,  Khizoglyphus  echinopus,  found  on  a  scale  of  bulb. 
1^  root-stem  eelworm,  Tylenchus  obtusus,  found  in  a  bit  of  decayed  matter  taken 
from  bulb. 
with  the  surrounding  soil,  and  cementing  this  so  as  to  adhere  to 
the  bulb.  Yellow,  turning  to  orown,  .spots  were  also  present  on 
the  first  leaf,  shown  at  c.  (3)  A  blue  mould,  in  a  roundish  patch, 
was  present  at  d.  (4)  Black  spots  were  conspicuous  on  the  sur¬ 
face  of  the  bulb  at  e,  and  streaks  of  dark  brown  matter  at  f, 
evidently  due  to  decay  of  the  outer  scales  of  the  bulb. 
Nothing  more  was  discerned  by  the  naked  eye,  and  no 
organic  body  revealed  by  the  aid  of  a  pocket  lens.  On  sub¬ 
jecting  a  portion  of  the  yellow  mucus  from  the  point  b  on 
the  bulb  A  to  microscopic  .scrutiny,  the  bodies  shown  at  B  were 
revealed,  and  a  similar  yellow  mucus  taken  from  the  vessels 
and_  intercellu^r  spaces  of  the  fundamental  tissue  at  the  points 
c  yielded  similar  bodies.  These  micro-organisms  are  bacteria, 
known  to .  bacteriologists  as  Bacterium  hyacinthi,  and  as 
infection  of  healthy  plants  with  the  yellow  mucilage  produces  the 
disease,  are  rightly  regarded  as  cause  of  the  disease. 
The  blue  mould  on  the  bulb  A  at  d  was  found  to  be  the  fungus 
known  to  fungologists  as  Penicillium  glaucum,  commonly 
a  saprophyte  on  dead  and  decaying  parts  of  foliage,  fruits,  anil 
roots  (including  bulbs).  It,  however,  by  no  means  leads  an  abso¬ 
lutely  saprophytic  mode  of  life,  though  it  commonly  begins  as 
such,  for  it  sometimes  causes  the  decay  of  adjacent  living  tissues, 
and  may  even  eat  up  bulbs,  especially  Tulips  and  Narcissus,  being 
frequently  associated  with  basal  rot  and  central  decay,  by  its 
virus  breaking  down  living  tissue,  and  thus  preparing  the  way 
for  its  passage  from  a  saprophytic  to  a  parasitic  mode  of  life. 
A  fruiting  branch  of  this  very  common  mould,  often  found  on  the 
surface  of  jam,  is  shown  at  C. 
The  internal  state  of  the  bulb,  shown  in  vertical  section  in 
Fig.  2  at  D,  showed  a  somewhat  different  state  of  affairs  to 
that  presented  by  the  external  .surface.  Its  base,  or  rooting  part, 
g,  was  quite  sound,  also  the  lower  portion  of  the  bulb  at  h.  At 
the  upper  part  the  bulb  scales  were  more  or  less  decayed,  some 
to  a  considerable  extent,  as  indicated  by  the  dark  portion  at  i. 
Bark  spots  also  were  present  at  the  point  j,  on  the  young 
growth  of  the  current  year.  This  (k)  was  otherwise  quite 
healthy,  and  the  flower  spike  of  the  coming  year  or  season  present 
in  embryonic  formation,  shown  at  1. 
So  much  for  cursory  observation.  Turn  we,  therefore,  to 
aided  scrutiny,  where  a  pocket  lens  brings  into  view  an  animal 
of  the  Arachnoidea  order,  family  Acaridee,  sub-family  Tyrogly- 
phidee,  by  name  Rhizoglyphus  echinopus,  a  very  common  pest 
on  Hyacinth  bulbs  and  roots  of  various  plants.  It  is  represented 
-at  E  in  the  adult  state,  as  taken  from  off  a  scale  of  the  bulb. 
!  A  bit  of  the  decaying  portion  of  a  bulb  .scale  also  yielded  the 
animal  shown  at  F,  a  member  of  tbe  Vermes,  or  worms  order, 
family  Nematodea,  by  name  Tylenchus  obtu.sus,  or  blunt  eelworm. 
Thus  we  have  four  micro-organisms  brought  to  view  by  aid  of 
the  niicroscope,  two  vegetable:  Bacterium  hyacinthi  and  Peni- 
cillium  glaucum;  and  two  animal:  Root  mite  (Rhizoglyphus 
echinopus)  and  root-stem  eelworm  (Tylenchus  obtusus),  and, 
beset  with  a  comsortism  of  parasites,  three  of  them,  if  not  all 
four,  capable  of  setting  up  disease  by  inoculation  or  presence. 
Which,  then,  of  the  four  is  responsible  for  the  di.sea.sed  .state  of 
the  Roman  Hyacinth  bulb  ? 
On  taking  a  bit  of  the  diseased  tissue  from  the  points  on  the 
young  grO'.vth  marked  j,  we  find  that  the  vessels  of  the  leaf  and 
the  intercellular  spaces  contain  a  yellow  mucus,  and  this  teem¬ 
ing  with  bacteria.  Not  any  of  the  other  bodies  are  found  there, 
hence  the  deduction  that  the  bacteria  are  tbe  camsing  agent,  the 
yellow  mucus  located  in  the  cells  and  intercellular  spaces  of  the 
leaf  occasioning  the  yellow  spots  on  the  leaf.  The  further  fact 
is  also  established  that  the  disease  commences  at  the  upper  part 
of  the  plant,  even  on  the  leaves  above  ground,  commonly  at 
the  tips  or  margins,  and  probably  through  minute  openings 
situated  there,  and  called  water  pores.  On  the  bulb  we  find  the 
disease  commencing  at  the  upper  part,  or  tips,  of  the  scales, 
and  passing  downwards  in  the  bulb  and  occupying  distinct  areas 
from  the  other  bodies.  Probably  the  mites,  and  even  the  eel¬ 
worm,  facilitate  the  infection  by  bacteria  through  breaking  down 
the  cuticular  tis.sues,  and  thus  allowing  the  yellow  bacterium 
to  easily  enter  the  tissues,  but  this  rests  upon  nO'  sure  founda¬ 
tion,  and  the  only  fact  deducible  is  that  of  the  environal  con¬ 
ditions  being  extremely  foul,  and  this  occasioned  by  disregard  of 
the  measures  known  as  cleanliness.  Infection  must  be  brought, 
and  it  genei’ally  finds  billet  where  means  have  not  been  adopted 
to  prevent  infection,  whether  from  root  mites,  eelworm,  bacteria, 
and  fungi.  We  may,  therefore,  glance  at  the  means  for  prevent¬ 
ing  the  spread  of  infection. 
(1)  Burn  all  diseased  bulbs,  not  throwing  them  on  the 
manure  heap,  which  means  securing  a  recurrence  of  the  disease. 
(2)  When  a  disease  appears,  remove  the  diseased  plants,  and  take 
repressive  measures  in  respect  of  the  remainder.  (3)  Avoid  fresh 
or  green  manure,  only  using  old  and  thoroughly  rotten  manure, 
or  other  animal  or  vegetable  matter,  for  digging  into  the  soil  or 
mulching  the  surface.  (4)  Reject  all  bulbs  produced  by  diseased 
plants,  as  they  perpetuate  the  disease.  (5)  Avoid  massing  plants 
of  the  same  kind  together  whenever  circumstances  permit.  (6) 
Attend  to  the  rotation  of  crops,  not  growing  bulbs,  and 
especially  the  same  kind,  indefinitely  on  the  same  ground,  this 
being  the  best  means  of  ridding  the  soil  of  any  pest. 
For  further  repressive  measures,  the  following  suggestions 
may  be  useful : — (1)  Dust  affected  bulbs  thoroughly  with  a  mixture 
of  two  parts  air-slaked  lime  and  one  part  flowers  of  sulphur,  or 
rub  the  bulbs  well  in  the  mixture.  The  lime  acts  well  on  the 
bacteria,  eelworm,  and  dead  or  decaying  matter,  and  the  sulphur 
is  very  hateful  to  the  root-mites  and  destructive  of  the  fungus. 
(2)  Use  no  form  of  vegetable  or  animal  matter  as  manure,  or 
a  conij)onent  of  compost,  but  thoroughly  rotted.  If  the  soil  is 
full  of  organic  matter,  whether  from  dressings  of  manure,  leaf 
■  mould,  decayed  refuse,  or  debris  of  plants,  apply  a  dres-siiig  of 
freshly  burned  lime,  slaked  with  the  .smalle.st  quantity  of  water 
necessary,  to  cause  it  to  fall  into  an  apparently  dry  powder, 
using  11b  of  the  quicklime  per  square  yard,  and  point  in  lightly. 
Afterwards,  on  the  dug  ground,  apply  4oz  of  kainit  per  square 
yard,  and  leave  for  the  rain  to  work  in.  For  mixing  with  com¬ 
post  shortly  in  advance  of  employing  for  potting  purposes,  use  a 
mixture  of  two  parts  basic  cinder  phosphate  and  one  part  best 
quality  kainit  in  the  proportion  of  2  per  cent,  of  the  compost, 
mixing  well,  and  turning  at  least  twice,  at  intervals  of  ten  days 
or  a  fortnight. 
It  is  only  recently  that  bacteria  have  been  connected  with 
plant  pathology ;  numerous  plant  diseases,  however,  are  now 
attributed  to  bacteria,  some  truly,  others  doubtfully  so.  Of  the 
former,  there  can  be  no  doubt  as  regards  Hyacinth  bacteriosis. 
It  attacks  the  bulbs  in  the  resting  condition,  and  shows  itself 
in  the  foliage.  The  attack  in  the  resting  condition  is  probably 
only  a  continuation  of  the  disease  set  up  in  the  foliage,  descended 
to,  and  abiding  in,  the  bulb  in  the  resting  condition,  then 
accelerated  by  the  confined  circumstances  of  storing,  and  even 
of  packing  in  quantities  for  exportation.  The  presence  of  the 
parasite  is  indicated  by  the  appearance  of  yellow  spots  on  the 
bulb  or  leaves,  and  these  spots  contain  a  yellow  mucus  teeming 
with  bacteria.  If  affected  bulbs  ai-e  isolated  and  kept  di-j^,  air 
playing  about  them,  the  bacteria,  and  even  eelworm,  are  retarded 
in  their  destructive  work  ;while  the  root-mites  and  fungus  thrive 
in  corresponding  measure  on  the  diseased  bulb  ;  at  least,  such  is 
the  case  as  observed  on  the  particular  bulbs  submitted  to  tbe 
Editor  by  “  Chelwood.”  The  whole  of  the  bulbs  wei-e  devoid  of 
flower  spikes  for  the  current  season’s  blooming,  hence  I  conclude 
that  the  foliage  had  been  attacked  by  bacteria  in  1901,  and  the 
bacteriosis  had  been  retained  in  the  bulbs,  it  being  only  a  matter 
of  favouring  conditions,  such  as  contact  with  damp  soil,  or  even 
damp  confined  environment,  for  the  rapid  development  of  the 
bacteria. 
