June  11,  1896. 
JOURNAL  OF  HORTICULTURE  AND  COTTAGE  GARDENER. 
545 
(Macrosporium  commune  var.  solani),  fig.  91,  A  j.  This  infeitation 
is  easily  detected  by  the  leaflets  of  the  plant  attacked  turning 
inwards  and  upwards  (fig.  92,  C),  which  also  is  a  characteristic  of  dry 
rot  fungus  (Fusarium  solani),  the  leaves  becoming  brown  and 
streaks  of  discolouration  appearing  on  the  fruit,  especially  the 
FIG.  92.— FUNGUS  IN  POTATOES  OK  TOMATOES. 
C,  infested  Potato  top  :  s,  stem  girdled  by  fungus ;  t,  transverse  section  of  stem,  half 
natural  size  ;  u,  the  same  enlarged  five  diameters  ;  v,  vascular  tissue  ;  w,  point  of 
break  ng  forth  of  fungal  outgrowths.  D,  Diplocladium  solani,  first  stage  of  fungus 
from  mycelial  hyphae.  E,  Fusarium  solani,  second  stage  of  fungus,  which  is  some¬ 
what  ousingand  often  accompanied  with  bacteria.  F,  Hypomyces  solani,  final  or 
resting  stage  of  fungus;  x,  formation  of  resting  spore;  y,  mature;  y  1,  single 
growth  from  resting  spore ;  z,  resting  spore  pushing  two  growths  ;  z 2,  ordinary 
pro- mycelium  ;  23,  pro-mycelium  producing  Diplocladium  solani.  Recuperation  of 
Potato  plant  from  above  attacked  part ;  a,  root ;  b,  tubes  from  a  shoot ;  c,  tuber¬ 
like  shoot  with  growing  leaf  eye,  both  capable  of  resting  and  of  reproducing  or 
continuing  the  plant., 
young,  and  at  or  near  the  eye.  The  plants  so  affected  give  way 
suddenly,  the  tops  withering  without,  as  the  saying  is,  “  cause  or 
reason.” 
Some  “  black  stripe,”  especially  in  plants  of  plethoric  habit,  is 
simply  Potato  disease  fungus  (Phytophthora  infestaDs),  and  it  also 
is  a  frequent  cause  of  “drooping  disease  ’’and  “sudden  collapse.” 
Attacked  plants  generally  assume  a  temporary  plethoric  deep  green 
growth,  as  if  overfed  or  too  liberally  supplied  with  nitrogenic 
manure,  but  the  leaves  soon  begin  to  curl,  brown  spots  appearing 
on  the  leaflets,  petioles,  and  stems,  even  on  the  footstalks  of  the 
fruit  and  on  this  itself,  when  it  is  all  over  with  the  plant. 
Further,  in  the  early  stages  of  scab  fungus  (Cladosporium 
fulvum,  Cooke)  the  appearance  of  affected  parts  closely  resemble 
“  black  stripe  ”  on  the  fruit,  but  the  stripe  or  streaks  soon  form 
depressed  blotches,  through  the  cuticle  of  which  the  outgrowths 
may  or  may  not  break  through  and  spread  the  malady.  Scab 
fungus  is  somewhat  prevalent  this  season,  and  there  are  a  few  cases 
of  the  worst  of  diseases  that  attack  the  Potato  and  Tomato,  which 
also  cause  a  “  sudden  collapse  ”  of  the  plants,  similar  to  that 
produced  by  Macrosporium  commune  var.  solani.  It,  however, 
chiefly  attacks  the  plant  by  the  root  stem  or  roots,  and  ascending 
by  the  stem  acts  similarly  to  Fusarium  solani. 
Unfortunately  the  fungus  (Sclerotinia  sclerotiorum,  31ass.) 
does  not  confine  its  attacks  to  Solanaceas,  but  has  beer  found  on 
Cabbage,  Beet,  &c.,  and  always  as  a  malignant  organism,  called  at 
different  times  Sclerotinia  libertiana,  Hymenoscypha  sclerotiorum, 
and  Peziza  postuma.  Under  the  latter  name  it  was  found  very 
disastrous  to  Potato  crops  in  Ireland  in  1880,  and  is  figured  and 
described  by  Mr.  W.  G.  Smith,  in  “Diseases  of  Field  and  Garden 
Crops,”  page  15.  No  mention  is  therein  made  of  a  conidial 
condition,  therefore  it  would  be  interesting  to  know  if  this  has 
been  ascertained,  and  what  it  infests.  Massee  is  equally  silent 
upon  this  point. 
The  “  black  stripe  ”  and  Sclerotinia  collapse  are  certainly 
induced  or  fostered  by  decaying  vegetable  matter  in  the  soil.  This 
is  not  a  bad  thing  in  itaelf ,  but  it  becomes  so  when  in  excess  of  the 
inorganic  elements,  especially  lime.  A  good  dressing,  therefore,  of 
quicklime  is  sufficient  to  prevent  “  black  stripe,”  as  caused  by 
Fusarium  solani,  from  attacking  Tomato  plants,  and  is  useful 
against  other  fungi  by  fortifying  the  hosts  with  that  element.  If 
this  be  done  annually  as  a  preventive  measure  there  is  little  to 
dread  from  “  black  stripe  ”  through  the  soil.  In  bad  cases  it  may 
be  necessary  to  have  recourse  to  gas  lime,  but  this  is  not  nearly  so 
good  for  the  soil  and  plants  as  quicklime,  nor  does  it  act  on 
vegetable  matter  to  anything  like  the  same  extent  as  a  reducer  of 
organic  matter  into  the  nutrient  elements  essential  for  the  health 
of  plants. 
In  addition  to  the  lime  dusting  with  Bordeaux  mixture  in 
powder  is  a  necessity  if  freedom  from  Tomato  diseases  is  expected. 
The  dusting  should  commence  early,  continuing  it  at  intervals 
from  the  plants  being  a  foot  in  height,  so  as  to  give  the  growths  as 
made  a  protective  coating  up  to  the  time  the  last  formed  fruits  are  a 
quarter  to  half  grown.  The  powder  should  contain  10  per  cent, 
sulphate  of  copper,  and  the  finest  possible  coating  is  sufficient  to 
destroy  any  fungus  spore  alighting  upon  it  and  pushing  a  germinal 
tube.  The  advertised  fungicides,  such  as  Fostite,  answer  admirably, 
and  are  better  for  use  under  glass  than  liquid  applications.  Even 
a  5  per  cent,  sulphate  of  copper  powder  answers  for  the  semi- 
superficial  scab  fungus,  dusting  the  whole  plant  and  rubbing  a  little 
of  the  powder  on  the  scabbed  parts  of  fruit  with  the  finger.  This 
will  often  save  otherwise  doomed  fruit,  and  beyond  a  slight  mark 
or  marks  not  prejudice  the  fruit  for  using  purposes,  only  take  care 
to  first  dip  them  in  a  cider  vinegar  solution,  afterwards  rinsing  well 
in  clear  water  and  drying  in  a  current  of  air. 
As  illustrating  the  growth  of  the  mycelial  hypha  in  the  Tomato 
stem  of  the  “  black  stripe  ”  fungus  and  the  general  appearance  of 
an  affected  stem,  as  shown  in  section,  the  engraving,  fig.  93,  will  be 
useful  to  growers  for  purposes  of  identification. 
From  the  foregoing  it  will  be  seen  that  “  black  stripe  ”  proceeds 
from  the  soil  and  ascends  by  the  woody  fibres  of  the  stem  to  the 
fruit ;  there  it  forms  resting  spores  in  the  integument  of  the  seeds, 
and  by  the  transportation  of  these  may  be  transmitted  to  the  ends 
of  the  earth.  The  important  points  are  therefore  to  prevent 
infection,  and  if  infection  occur  burn  the  whole  plant,  never  saving 
seeds  from  diseased  plants  — G  Abbey. 
FIG.  93.— SECTIONS  OF  DISEASED  TOMATO  STEM. 
A,  small  root ;  a,  enlarged  three  diameters ;  b,  central  part  brown  and  destroyed  ; 
c,  cortical  ceils,  tinged  with  brown.  B ,  section  of  stem  just  above  ground,  natural 
size;  d,  enlarged  three  diameters;  e,  healthy  cortical  tissue;/,  normal  (white) 
pith  cells  :  g,  woody  fibres  diseased  (brown).  C,  section  of  stem  9  inches  above 
the  soil ;  i,  clear  cortical  layer  ;  j,  healthy  pith ;  k,  woody  fibre  stained  pale  brown  ; 
l,  section  enlarged  three  diameters  ;  references  as  for  C.  D,  section  at  18  inches 
from  the  soil  (natural  size)  enlarged  three  diann  ters  (right  hand)  : — m,  pith  cells, 
quite  white ;  ?t,  woody  fibres,  clear ;  o,  vascular  bundles  unstained,  and  epidermis 
perfectly  healthy.  E,  mycelial  hypha  from  a  longitudinal  section  of  a  root,  and 
representing  the  older  ascending  hypha.  F ,  prostrate  and  growing  hypha  ;  p,  cell 
of  hypha  in  process  of  forming  a  resting  spore  (Hypomyces  solani) ;  q,  special 
cell  ultimately  forming  a  resting  spore. 
