94 
JOURNAL  OF  HORTICULTURE  AND  COTTAGE  GARDENER. 
July  25,  1901. 
The  Diamond-back  moth,  Plutella  cruciferarum. 
We  are  always  in  difficulties  of  some  sort — either  the  weather  is 
too  hot  or  too  dry,  too  cold  or  too  wet.  We  never,  or  rarely,  seem 
to  get  a  happy  medium,  and  to  farm  well  and  successfully  we  need 
to  have  resources  within  ourselves  ready  to  fall  back  upon  to  meet 
every  contingency.  Do  as  we  will,  and  strive  as  we  may,  there  are 
times  and  seasons  that  quite  overmaster  us  ;  there  are  circumstances 
that  we  cannot  control,  and  alien  forces  against  which  we  cannot 
stand. 
The  earliest  insect  foe  we  have  to  face  is  wireworm  ;  but  there 
are  certain  remedies  which,  if  applied  in  time,  will  stop  the  worst 
of  the  ravages.  Then  as  stock  goes  out  to  pasture,  we  have  for  the 
bullock  and  cow  the  warble  fly,  for  the  sheep  the  tiresome  maggot, 
or  mawk,  as  it  is  called  in  some  parts  ;  the  horse  has  the  hot  fly,  and 
poultry  parasites  innumerable. 
Then  we  turn  our  attention  to  the  Turnip  crop.  Some  years  all 
goes  well — the  soil  is  in  capital  condition,  the  weather  everything 
one  could  desire,  and  the  young  plants  get  quite  away  without  let 
or  hindrance.  Happy  the  case  when  it  is  so,  for  at  the  best  of 
times  roots  are  an  expensive  crop,  and  some  great  and  learned 
authorities  are  doubtful  if  even  a  bumper  crop  pays  for  production. 
That  is  too  great  a  question  to  go  into  ;  suffice  it  to  say  we  should 
feel  sadly  lost  without  our  roots,  and  should  not  know  where  to 
turn  for  their  equivalent.  Of  course,  on  strong  land  none  but  the 
most  sanguine  ot  men  will  attempt  their  growth  ;  everything 
militates  against  successful  culture,  and  the  expense  and  disappoint¬ 
ment  are  tremendous.  So  far,  this  summer  has  been  (taking  the 
country  generally)  an  unfortunate  one  for  root  crops — land  too  dry 
to  properly  work,  seed  beds  too  rough,  no  warm  showers,  or  very 
few  of  them,  backward  plants  with  no  chance  to  grow  because  an 
easy  prey  to  “  fly.”  Healthy  vigorous  plants  do  not  seem  to  attract 
“  fly,”  or  else  their  vigour  enables  them  to  outgrow  their  enemies 
and  get  right  away.  We  have  not  heard  of  the  Mangold  weevil  this 
year,  though  we  have  heard  of  acres  of  dormant  seed,  which,  alas !  we 
fear  will  germinate  only  too  late  to  be  of  substantial  value. 
We  began  to  think  we  were  fairly  out  of  our  Turnip  difficulties, 
at  least  for  the  present,  when,  lo,  the  note  of  alarm  is  sounded  again, 
and  this  time  the  cry  is,  “  The  diamond-back  is  upon  us.”  This  is 
by  no  means  the  first  visitation,  for  we  find  there  were  invasions  of 
this  enemy  in  1837,  1851,  1883,  1888,  and  also  in  1891.  The  one  in 
1891  we  remember  well,  as  the  ravages  were  greatest  in  the  eastern 
counties  from  Kent  to  Aberdeen.  It  is  a  funny  circumstance,  but 
nevertheless  true,  that  a  calamity  which  affects  the  crops  or  stock  of 
others  is  soon  forgotten  by  the  more  fortunate ;  it  is  only  when  the 
trouble  comes  home  that  the  circumstances  are  indelibly  fixed  on  the 
memory.  1891  was  with  us  a  dry  hot  season,  and  we  have  lively 
recollection  of  the  riddled  leaves,  and  the  flight  of  hosts  of  moths. 
About  the  middle  of  July  it  usually  makes  its  appearance,  and  in 
case  there  may  be  novices  who  do  not  know  it  by  sight,  we  will  try 
and  describe  its  appearance.  It  is  from  five  lines  to  half  an  inch 
long  when  resting  with  folded  wings.  The  wings,  when  expanded, 
have  a  breadth  of  nearly  two-thirds  of  an  inch.  The  colour  is  light 
brown  shaded  with  grey,  and  the  diamond  marks  are  plainly  visible 
upon  the  back  when  the  insect  is  at  rest.  These  marks  are  formed  by 
the  arrangement  of  the  light  coloured  edges  or  margins  of  the  wings. 
The  peculiar  tilt  of  the  wings  at  their  ends  forms  a  kind  of  tuft.  The 
under  surface  of  the  body  is  grey,  or  pale  grey.  The  first  brood  of 
moths  comes  early  from  the  chrysalids  which  have  withstood  the 
winter,  and  then  the  female  moth  proceeds  to  lay  her  eggs  on  the 
under  side  of  wild  cruciferous  plants  and  such  cultivatedj^ones  asfmay 
be  then  growing.  There  is  no  doubt  about  it,  that  in  a  favourable 
season  there  may  be  two,  if  not  more,  broods.  Food  is  most  abundant, 
f"f  they  will  live  upon  all  kinds  of  Turnips,  Cabbage,  Broccoli, 
Brussels  Sprouts,  Kale,  Raje,  Mustard,  wild  Mustard,  Radishes, 
Horseradish,  Stocks,  Wallflowers,  and  no  end  of  other  things. 
Now  what  is  to  be  done  to  get  rid  of  the  pest?  Remember  they 
are  iound  on  the  under  side  of  the  leaf  they  attack.  It  is  all  very  well 
to  recommend  a  dressing  ( f  soot  and  lime ;  one  part  lime  to  three  parts 
soot  and  sulphur,  1  bushel  soot  to  2  or  3  lbs.  sulphur,  distributed  at 
the  rate  of  3  or  4  bushels  per  acre,  are  nice  mixtures,  but  the  question 
is  whether  the  distributor  does  not  get  a  greater  benefit  than  the  moth 
or  caterpillar.  It  is  well  nigh  impossible  to  get  at  the  evil  so.  A 
spray  of  carbolic  acid  and  paraffin,  quassia  and  softsoap,  would  do  if 
you  could  insure  a  thorough  washing.  One  chemist  advises  Paris 
green,  8  ozs.  to  100  gallons  of  water.  This  is  a  horribly  poisonous 
mixture,  and  should  be  used  with  the  greatest  care.  There  is  a  better 
way  still,  recommended.  Tie  branches  of  Broom,  Birch,  or  any 
similar  plant,  to  any  ordinary  drill  hoe  (scruffier),  so  that  when  hoeing 
the  branches  may  brush  the  Turnip  leaves  and  knock  off  the  cater¬ 
pillars  ;  follow  at  once  with  a  second  hoe  or  a  light  drill  plough.  If 
the  Turnips  at  the  time  of  the  attack  have  not  been  singled,  leave 
them  alone  and  give  a  little  stimulating  manure,  and  do  not  worry,  is 
the  advice  of  a  practical  neighbour. 
It  was  noticed  in  1891  that  various  kinds  of  birds  were  effective 
enemies  of  the  caterpillars  of  this  moth.  Rooks,  starlings,  peewits, 
golden  plover,  and  seagulls  did  good  work.  We  feel  sure  if  the  black¬ 
headed  gull  has  not  left  its  inland  breeding  place  for  the  sea  it  would 
do  its  share  ;  but  with  us  the  gull  is  generally  away  and  clear  of  us 
by  middle  of  July.  Small  birds,  too,  where  any  are  left,  are  caterpillar 
enemies  ;  it  is  a  pity  they  are  not  more  discriminating.  We  have 
Turnip  fields  all  round,  but  they  appear  infinitely  to  prefer  a  field  of 
immature  Barley,  where  they  are  not  at  all  wanted.  Of  course, 
what  would  save  the  Turnips  would  be  heavy  and  continuous  rain  ; 
rain  that  would  wash  off  the  caterpillar  and  give  the  plants  a  new 
lease  of  life,  and  in  this  fickle  climate  of  ours  rain  may  come  at  any 
moment. 
There  is  another  little  matter  we  think  worthy  of  attention.  Some 
years  ago  there  was  much  talk  of  a  forage  plant  called  Lotus 
corniculatus,  in  appearance  not  unlike  Lady’s  Finger.  The  value  of 
this  plant  consisted  in  its  power  of  thriving  on  hot  sandy  soils  in  dry 
weather.  We  believe  it  was  first  grown  in  Norfolk.  At  the  time 
we  speak  of  we  were  farming  some  sandy,  blow-away  land,  and  we 
tried  Lotus  corniculatus  in  our  seed  mixture.  It  proved  a  very 
valuable  addition  to  the  pasture,  and  certainly  throve  as  no  other 
growth  would,  under  most  unfavourable  conditions.  We  ought  to  say 
this  pasture  was  laid  down  for  three  years,  as  it  was  practically  of 
very  little  value  for  anything  else.  As  long  as  the  plant  was  small 
and  well  eaten  down  it  was  frost  proof ;  but  should  it  attain  any  size, 
and  severe  weather  set  in,  it  is  in  danger  of  being  cut  down. 
Now,  of  course,  we  may  be  nearing  the  end  of  the  drought  cycle, 
or  we  may  be  approaching  severe  winters  again  ;  certainly  for  the  last 
two  or  three  there  have  been  no  frosts  that  would  materially  injure 
any  vegetation.  Of  course  our  readers  may  have  tried  Lotus  and 
found  it  wanting  in  the  qualities  they  desire.  But  at  any  rate,  we 
think  an  owner  of  hot,  dry  land  might  do  worse  than  sow  Lotus 
corniculatus. 
Work  on  tlie  Home  Farm. 
“  The  corn  fields  are  whitening  to  the  harvest,”  and  that  busy 
period  seems  likely  to  be  here  before  we  are  ready  for  it.  Swedes  are 
not  all  hoed  yet,  white  Turnips  have  hardly  been  touohed  (only  the 
earliest  ones),  then  all  have  to  be  run  over  again  for  weeds  and  doubles, 
so  there  is  muoh  to  be  done.  Some  piece  workmen  were  observed  this 
morning  going  to  work  an  hour  earlier  than  usual.  That  is  the  way 
to  get  work  done,  but  the  men  will  not  make  long  days  now  as  readily 
as  they  once  did.  Of  the  party  we  saw  none  would  be  under  fifty  years  of 
age.  The  new  generation  would  not  do  such  a  thing,  as  to  go  to  work 
at  5.30  a.m. 
There  is  talk  of  harvest  in  a  fortnight.  All  we  can  say  is  that  the 
grain  will  not  be  properly  filled  in  that  time.  We  want  a  good  twenty, 
four  hours’  rain  for  everything.  Barley  and  Oats  are  beginning  to 
suffer  muoh  ;  Turnips  and  Swedes,  though  not  in  dire  necessity,  would  be 
much  benefited,  whilst  midseason  Potatoes  are  giving  up  and  will  be  a 
very  light  crop.  Late  varieties  have  not  felt  the  drought  so  much,  but 
need  a  good  rain  at  once  to  keep  them  going  forward.  A  fortnight  of 
hot  sun  and  drying  winds  has  indeed  made  a  transformation. 
Peas  for  pulling  green  have  shrivelled  up  instead  of  filling  properly. 
All  kinds  are  ready  at  once  for  a  glutted  market.  We  see  an  army  of 
women  pulling  Peas  as  we  write.  Will  the  market  return  compensate 
for  the  labour  ? 
Good  progress  has  been  made  with  the  hay,  muoh  has  been  got  in 
perfect  condition  and  little  remains  out.  The  stacks  are  not  large, 
being  about  equal  to  last  year’s,  but  the  quality  is  very  good,  and  there 
will  be  no  waste.  Wise  farmers  will  get  their  hay  thatched  at  once,  for 
the  heat  is  sure  to  be  followed  by  thunderstorms,  which  may  spoil  a 
good  portion  of  the  roofing  if  not  protected. 
We  hear  of  local  appearances  of  the  diamond-backed  moth,  but  have 
not  observed  it  personally.  May  its  ravages  be  only  local,  for  we  have 
a  vividly  unpleasant  remembrance  of  its  visit  in  1891. 
Clover  stubbles  and  meadows  look  very  bare  and  brown  now  the  hay 
is  removed,  and  they  will  need  a  good  soaking,  or  there  will  be  little 
aftermath  for  the  lambs. 
