JOURNAL  OF  HORTICULTURE  AND  COTTAGE  GARDENER. 
June  30,  1898. 
5:u 
Council  will  continue  to  hold  their  examinations,  and  thereb}'  give 
encouragement  to  deserving  and  persevering  young  men  to  acquire  as 
full  a  know-ledge  as  possible  of  the  occupation  to  which  they  intend  to 
devote  their  lives. — W.  Neild,  Holmes  Chapel. 
[If  our  correspondent  thinks  the  Journal  of  Horticulture  has  the 
remotest  objection  to  these  examinations  he  makes  a  very  great  mistake. 
The  Secretary  of  the  E.Il.S.  could,  if  he  liked,  tell  him  quite  a  different 
story,  but  it  is  not  in  the  least  necessary.  At  the  same  time  it  is  in  the 
province  of  the  Joui-nal  to  register  differing  opinions  on  this  or  any  other 
subject  in  which  its  readers  are  interested,  and  this  will  be  done  so  long 
as  they  are  appropriately  espressed,  as  in  the  above  communication,  by 
an  esteemed  and  able  coadjutor.] 
DISEASED  BROCCOLI. 
The  specimen  from  “ K„  Dublin”  has  a  very  singular  appearance — 
Leaf  stout  and  leathery,  midribs  yellowish,  veins  more  so,  with  yellowish- 
white  patches  on  the  surface,  and  blackish  .spots  here  and  there  on  the 
golden  groundwork,  the  whole  set  off  by  a  broad,  more  or  less  erumpent, 
w  hite  or  silvery  margin,  very  conspicuous  from  the  contrast  of  the  latter 
with  the  purplish-green  parts  of  the  leaf,  which  were  the  only  normal 
portions. 
The  yellow  and  the  black  were  determined  as  a  peculiar  form  of  the 
so-called  “clubbing”  (of  Cabbages,  ike.),  and  “  finger-and-toe  ”  (of 
Turnips)  slime  fungus,  Plasmodiophora  brassicas,  and  the  white  as  the 
■•haracteristic  type  of  the  white-rust  disease  of  Cabbages  and  many 
cruciferous  plants,  the  fungus  named  Cystopus  candidus.  There  were, 
however,  no  outgrowths  of  this  parasite,  but  very  sparingly  those  of  the 
putrefactive  mildew  of  Cabbages  and  Turnips,  the  fungus,  Peronospora 
parasitica.  The  latter  is  very  often  associated  with  white-rust  fungus, 
sometimes  the  one  and  at  others,  the  other  being  in  the  ascendant— that 
is,  the  fertile  hyphte  of  Cystopus  candidus  may  break  through  the 
epidermis  of  the  host-plant  and  produce  innumerable  spores  (eonidia), 
these  being  distributed  as  visible  white  dust  when  the  infested  plant  is 
sharply  struck  by  foot  of  man  or  beast.  In  some  cases  (and  this  under 
consideration  represents  one)  the  putrefactive  mildew,  Peronospora 
])arasitica,  appears  first  and  absolutely  without  any  concurrent  outgrowths 
of  white-rust,  nor  do  any  in  such  instances  appear  afterwards,  the 
putrefactive  mildew  being  entirely  master  of  the  situation,  ousting  the 
other. 
These  trifles  are  the  very  root  of  the  evil,  and  narrow  the  thing  down 
to  two  forms,  which  may  be  still  further  reduced  to  one,  the  Myxomycete 
or  slime-fungus,  as  this  has  sprung  from  the  soil  and  entered  the  plant  by 
the  root-system.  But  the  parasite  must  not  be  confounded  with  ordinary 
“  clubbing  ”  or  “  finger-and-toe  ”  slime-fungus,  for  there  is  no  thickening 
of  the  parts,  the  plasmodia  simply  streaming  through  the  plant  cells  and 
breaking  them  down,  as  indicated  by  the  yellow  appearance,  and  the 
“  fruits  form  in  the  black  dots,  being  simply  spores  or  plasmodia  differ¬ 
entiated  and  enclosed  by  an  integument.  In  this  state  (resting)  it  closely 
resembles  a  “  bacteroid  ”  converting  free  nitrogen  into  assimilable  (by 
plants),  and  the  streaming  of  tho  plasma  in  the  tissues  of  the  living  plant 
so  much  accord  in  appearance  as  to  be  scarcely  distinguishable  from  each 
other.  Both  possess  Amseba-like  movements,  but  the  “  bacteroides”  an- 
symbiositic  or  helpful  to  the  host,  and  the  slime-fungus  parasitic 
(destructive  to  the  infested  plant). 
This  preliminary  appears  relevant,  from  the  circumstance  that 
“  K.,  Dublin”  alludes  to  the  disease  infesting  Plums,  Cherries  and 
Peaches.  ^  The  specimen  to  hand  (of  Broccoli)  has  an  analogous  con¬ 
nection  with  the  disease  known  as  browning  or  “brunure”  in  Vines,  a 
very  similar  micro-organism  infesting  the  common  Alder,  Alnus  glutinosa, 
and  its  leaves  often  have  the  whitened  appearance  at  their  margins^ 
ultimately  becoming  black  and  falling  off.  The  organisms,  however,  are 
quite  distinct,  or  they  assume  different  forms  according  to  the  host. 
That  submitted  by  your  able  correspondent  appears  identical  with  the 
“brunure”  of  the  Vine,  or  Plasmodiophora  vitis,  or  Pseudo-cominis 
Titis,  Debray. ^  This  I  have  found  on  Pelargoniums,  Orchids,  Tomatoes, 
Vines,  and  Kale,  the  “yellow”  always  preceding  tie  brown  or  black; 
and  sometimes  on  Brassicas,  not  always,  the  putrefactive  mildew- 
(Peronospora  parasitica)  also  presents  itself,  and  may  easily  be  mistaken 
for  the  real  culprit. 
I  have  given  a  brief  outline  of  the  disease  as  I  find  it  in  Nature,  and 
consider  that  it  may  be  referred  to  the  Pseudo-cominis,  being  merely 
a  variety,  as  found  on  the  Broccoli  examined,  the  other  bodies  being  a 
sequence.  But  let  no  one  run  away  with  the  impression  that  there  can 
be  no  harm  done  by  either  of  the  other  pests,  for  both  are  parasites, 
^mmonly  occurring  together,  and  also  separately,  as  before  stated. 
The  slime  fungus  in  this  case  is  the  cause  of  the  yellow  and  the  black. 
The  parasite  has  come  from  the  soil,  entered  the  plant  from  without,  even 
it  It  went  over  as  a  spore  with  the  seed,  and  this  is  a  main  pouit,  for 
no  treatment  can,  so  far  as  I  have  investigated,  enter  the  tissues  of  a 
living  plant  and  kill  micro-organisms  therein  without  prejudice  to  the 
host. 
The  cause  of  the  attack  is  (1)  presence  of  the  micro-organism,  and 
(2)  favouring  conditions  of  existence.  I  am  not  prepared  to  state 
positively,  but  I  consider  the  Pseudo-cominis  leads  a  free  as  well  as 
parasitic  mode  of  life,  and  there  is  hope  of  prevention.  Pi)r  this  purpose 
there  are  poisons,  the  most  commonly  used  being  that  of  fresh  gas  lime, 
which  I,  with  many  others,  have  frequently  advised  for  preventing  tlie 
clubbing  of  Cabbages  and  other  pests.  I  do  not  consider  it  has  any 
equal  for  killing  pests  infesting  land,  but  I  find  it  also  injures  the 
nitrifying  micro-organisms,  practically  sterilising  the  land  for  crops  for  a 
time. 
Por  bare  land  I  have  not,  however,  found  gas  lime  particularly 
hurtful  when  had  fresh  from  gasworks,  spread  evenly  on  the  surface,  and 
left  there  as  many  weeks  as  stones  or  tons  used  per  rod  or  acre.  I  have 
used  as  little  as  1  stone  per  rod,  or  1  ton  acre  when  land  must  be 
cropped  soon  afterwards,  and  from  that  up  to  5  stones  per  rod,  5  tons 
per  acre  on  foul  land,  this  being  a  maximum  amount,  and  thoroughly 
efficacious.  It  was  left  on  the  surface  for  six  weeks,  and  then  turned 
under.  I  have  tried  it  in  both  fields  and  gardens,  and  never  knew  it  fail, 
nor  even  do  much  harm  if  put  on  in  the  autumn.  This  I  advise,  but  it 
must  not  be  used  over  the  roots  of  crops,  bushes,  or  trees. 
Gas  lime  is  a  limited  substance,  I  therefore  pass  to  something  simp  er 
and  safer — namely,  lime.  The  nitrifying  micro-orgauisms  like  and' 
must  have  lime,  and  I  believe,  though  I  have  not  proved  it,  potash  and 
soda.  Lime  alone,  best  chalk,  or  if  vegetable  soil  magnesian,  1  to- 
10  tons  per  acre,  or  1  to  10  stones  per  rod,  are  the  amounts  in  which 
I  have  used  it,  except  for  particular  purposes,  and  always  to  the 
annihilation  of  slime  fungus.  Up  to  5  tons  as  a  preventive,  the  smaller 
quantity  (1  ton  or  1  stone  every  year),  and  then  the  amounts  as  per 
year  between  dressings.  I  consider  the  1  ton  or  1  stone  essential  on 
all  but  calcareous  soils.  By  this  I  mean  those  having  the  limestone  or 
chalk  mixed  with  the  surfacing  soil,  for  some  soils  on  those  formations 
need  liming  as  much  as  many  others. 
As  a  cure  the  quantity  must  not  be  less  than  5  tons,  better  the  10  tons 
per  acre  or  10  stones  per  rod.  Let  it  be  freshly  burned,  place  in  con¬ 
venient  lumps,  jixst  slake  so  to  cause  it  to  fall  to  a  fine  powder,  and 
spread  whilst  hot.  Leave  on  the  surface  for  a  time,  not  striving  to  plate 
it  in  contact  with  tho  pests,  but  let  the  lime  go  to  them  in  a  natural  way.. 
The  rains  will  come  soon  enough,  and  the  lime  will  get  down  quite  a» 
fast  as  is  desirable.  It  acts  mainly  on  the  organic  matter  in  the  soil, 
and  I  believe  the  ammonia  gas  plays  the  part  of  killing  the  micro¬ 
organisms  and  pests.  Anyway,  as  the  lime  goes  in  the  pests  clear  out, 
and  the  crops  thrive  well  the  following  season.  But  this  depends,  for  if 
put  under  in  a  caustic  state  it  sterilises  the  land  for  a  time. 
Another  application  that  I  have  found  of  great  service  in  killing 
Plasmodiophora  brassicas  or  Pseudo-cominis  vitis  is  best  chalk  lime,  air- 
slaked  or  freshly  burned,  and  slaked  with  the  smallest  quantity  of 
water  to  cause  it  to  fall  to  a  fine  apparently  dry  powder  ;  using  when 
cool  twenty  parts  of  this  to  one  part  of  kainit,  1  to  10  tons  per  aoe,  or 
1  to  10  stones  per  rod.  Broadcast  it  as  soon  as  mixed,  and  leave  it  on  the 
top  for  a  time  on  arable  land  or  vegetable  ground  before  ploughing  or 
digging  under,  applying  in  autumn.  On  sour  grass  laud,  orchards, 
and  fruit  plantations  the  rains  will  do  the  needful  in  washing  in.  But- 
though  the  mixture  may  be  used  I  think  it  better  to  use  the  lime 
separately,  freshly  burned,  slaked,  and  put  on  hot,  then  follow  with 
the  kainit  as  soon  as  cool  or  not  later  than  in  a  few  days.  Pive  tons 
of  lime,  and  5  cwt.  of  kainit  per  acre,  or  5  stones  of  lime  and  1  stone 
of  kainit  per  rod  will  be  required  on  tainted  land,  and  double  quantity  on. 
badly  infested  ground. — G.  Abbey. 
GLEAN  VEKSus  DIRTY  POTS. 
Undee  the  heading  “  Young  Gardeners’  Domain,”  in  the  Journal  of 
June  2nd,  page  469,  “A  Young  Ross-shire  Gardener ”  has  something  to 
say  on  the  subject  of  “clean  versus  dirty  pots.”  The  remark,  “clean 
pots  are  not  necessary  for  healthy  growth,”  which  was  one  of  the  points- 
in  my  lecture  on  fruit  growing  which  recently  appeared  in  your  pages, 
is  evidently  more  than  this  young  gardener  can  swallow.  He  is  to  be 
commended  in  doing  what  he  has  done — going  direct  to  Dr,  “Journal ’’ 
with  his  complaint.  I  am  glad  he  has  brought  the  matter  up,  and  sorry 
I  could  not  reply  sooner.  I  have  had  several  letters  on  this  subject,  and 
as  there  seems  to  be  a  misunderstanding  as  to  what  I  meant,  I  am  glad  of 
this  opportunity  to  make  it  clear. 
First,  let  me  say  that  the  part  of  the  pot  I  referred  to  is  the  inside 
only,  and  am  not  to  be  understood  as  advocating  dirty  and  untidy  habits. 
Although  the  washing  and  cleanliness  of  the  outside  of  the  pots  in  which 
plants  are  grown  is  of  the  first  importance  in  private,  and  only  a  secondary 
consideration  in  market  establishments,  still,  in  the  latter,  where  we  find 
men — often  young  men — with  considerable  latitude  in  the  management  of 
the  plants  under  their  charge,  make  cleanliness  and  order  a  first  con¬ 
sideration,  we  generally  find  the  plants  doing  well,  and  is  a  sure  indicatiorr 
of  a  good  w  rrkman. 
Your  correspondent  conjures  up  the  shade  of  his  dear  old  master.  It 
is  not  so  much  these  dear  old  shades  I  wish  to  be  at,  as  those  younger 
men  of  the  present  generation,  who  possess  so  many  advantages  for- 
keeping  themselves  abreast  of  the  times  in  all  things  pertaining  to  their 
calling,  but  who  persist  in  following  a  blind  rule-of-thumb  practice,  for 
no  other  reason  than  “that  is  how  it  was  done  when  I  served  my  time.” 
I,  too,  have  served  under  some  of  these  “  old  shades,”  and  was  brought 
up  in  the  full  belief  that  cleanliness  inside  the  pot  was  essential  to  the 
proper  growth  of  the  plant. 
Nor  do  I  ever  remember  hearing,  or  seeing  anything  written  to  the 
contrary,  until  I  had  been  about  fifteen  years  at  the  profession.  Then  I 
went  to  a  place — the  largest  and  best  I  had  been  in — where  no  pots  were 
washed  before  use.  I  thought  it  rather  queer  practice  at  first,  but  when 
I  saw  the  plants  thrive  as  well  as  any  I  had  seen,  I  could  not  help 
deploring  the  wasted  time  and  money  annually  spent  all  over  the  country^ 
and  I  resolved  when  I  had  a  charge  of  my  own  I  should  certainly  follow 
