152 
THE  TROPICAL  AGRICULTURIST. 
[SliPT.  2,  18915. 
side  of  tlie  iiiiiiute  slit-like  opeuing  which  constitutes 
the  mouth,  and  is  placed  at  its  lower  extremity,  it 
bears  two  minute,  curved  and  probably  moveable 
spines.  At  the  end  of  the  short  fixed  arms  of  the 
pincers  of  the  feelers  open  the  ducts  of  t.ie  g ..n  is, 
which  furnish  the  viscid  secretion  wherewith  the 
animals  spin  their  protective  webs.  The  mandibles 
or  jaws  are  a pair  of  long  and  delicate  needle 
shaped  rods  which  ordinarily  lie  retracted  out  of 
sight  into  their  sheaths  i-eady  to  be  shot-out  with 
lightning  rapidity.  It  is  a remarkable  fact  that  the 
sheaths,  which  appear  to  be  none  other  than  the 
basal  joints  of  the  mandibles,  retain  their  primitive 
embryonic  distinctness  throughout  life  and  do  not 
coalesce  in  adult  life  so  as  to  form  a single  common 
sheath  as  they  are  said  to  do  in  T.  telarius.  It  is 
more  probable  that  the  leaves  are  punctured  by 
these  mandibular  needles,  and  that  the  two  little 
movable  spines  placed  at  the  sides  of  the  rostrum 
serve  only  to  keep  the  sucker-shaped  elevation  around 
the  mouth  closely  applied  to  the  wounded  spots  in 
order  that  the  buccal  pump  may  act  as  effectually 
as  possible,  than  that  the  latter  perform  the  double 
duty  of  lancets  and  retentive  hooks. 
I propose  for  the  tea  mite,  which  would  appear 
to  be  unknown  to  science,  the  name  of  Tetrani/chus 
bioculatus,  in  allusion  to  its  double  (really  two  pairs 
0'  eyes).” 
The  tea  mite  is  most  destructive  in  the  early 
part  of  the  season,  and  increases  at  such  a rate 
if  there  is  a drought  that  a tea  garden  appears  of 
a dull  biick-red  colour  even  when  viewed  from  a 
distance.  As  soon  as  the  heavy  rains  set  in  it  dis- 
appears from  the  eye,  but  considerable  numbers  must 
bo  lying  dormant  as  they  quickly  reappear  if  there  is 
a break  in  the  rains  accompanied  with  hot  sun. 
The  most  important  matter  so  far  as  planters  are 
concerned  is  the  discovery  of  an  effectual  remedy 
against  this  pest,  and  I take  the  following  from 
Indian  Museum  Notes.  Vol.  3.  No.  1.  Although 
experiments  have  not  been  conducted  on  a large 
scale,  and  therefore  further  tests  are  necessary  before 
pronouncing  a definite  opinion,  it  would  seem  that  a 
most  valuable  discovery  has  been  made : — ‘ A very 
complete  and  interesting  series  of  reports  by  Mr. 
G F riavfair,  on  the  results  experiments  conducted 
n Gachar  upon  the  subject  of  the  sulphur  treatment 
or  red  spider,  have  been  furnished  by  Messrs. 
Barry  and  Co.  Five  tons  of  refined  flowers  of 
sulphur  were  sent  up  to  the  garden  for  application 
as  a remedy  against  red  spider  {Tclramichus  bio- 
culatnti),  which  is  one  of  tire  tea  planter’s  most 
inveterate  enemies.  The  sulphur  was  applied  over 
an  area  of  138  acres,  and  the  results  appear  to  bo 
so  successful  that  the  treatment  seems  likely  to 
prove  of  the  very  greatest  value. 
“ The  method  adopted  was  to  put  the  sulphur  into 
bags  nifde  of  loose  woven  cloth  and  sprinkle  the 
tea  bushes  by  simply  shaking  these  bags  over  them. 
In  some  cases  the  bushes  were  first  splashed  with 
water,  but  in  localities  where  water  was  not  easily 
obtainable  the  sulphur  was  applied  without  any  pre- 
vious watering.  The  sulphur  was  found  to  adhere 
fairly  well,  even  on  dry  bushes,  in  spite  of  the  high 
wind  which  blew  both  at  the  time  that  the  sulphur- 
ing was  going  on  and  afterwards.  The  average 
cost  of  the  treatment  has  been  estimated  by  Mr. 
Playfair  at  Ils  8-4  per  acre,  including  the  price  and 
freight  of  the  sulphur  and  the  cost  of  application. 
The  sulphur  was  applied  in  the  first  instance  at  the 
rate  of  one  hundredweight  to  the  acre,  but  a large 
area  \vas  afterwards  sulphured  at  the  rate  of  two 
hundredweight  to  three  acres,  and  an  experiment 
was  made  over  eleven  acres  of  sprinkling  a mixture 
of  one  part  of  sulphur  with  two  parts  of  sifted  lime. 
Tlie  last  application  does  not  appear  to  have  been 
so  successful  as  the  undiluted  .sulphur.  Besides 
destroying  the  red  spider  most  effectively,  Mr.  Playtair 
is 'of  opinion  that  the  sulphur  treatment  is  also 
useful  against  the  mos()uito  blight  {IldopcUis  thetvova) 
whi'di  is  perliaps  an  tweii  more  destructive,  ))est  titan 
i-ed  spider.  Iljton  this  point  it  will  be  uselul  to  make 
fiuther  observations,  as  mites  (such  as  red  Bjtider) 
are  the  only  pest  against  which  sulphur  seems  to 
Jiave  hitherto  been ‘successfully  used  in  other  parts 
of  the  world. 
“ It  may  be  noticed  that  washes  made  of  soap 
and  sulphur  combined  have  been  rocomniended  both 
in  the  United  States  and  in  England  for  use  against 
mites  like  the  red  spider.  The  wash  is  sprayed 
on  to  the  plants  by  mcaiij  of  a force  pump  fitted 
with  a nozzle  to  give  a very  finely  divided  spray. 
This  method  of  applying  the  sulphur  may  possible 
prove  cheaper  and  more  effectual  than  dusting  it 
on  to  the  leaves,  though  Mr.  Playfair’s  experiments 
with  sulphur  in  powder  seemed  so  successful  as  to  leave 
little  to  be  desired.  Compounds  of  soft  soap  and 
sulphur  can  now  be  purchased  in  England  ready 
made,  so  as  only  to  require  the  addition  of  water.” 
It  is  well  to  know  that  this  insect  can  be  of  use 
to  man,  as  the  following  curious  note  will  show : — 
‘‘  A note  written  some  years  ago  by  Mr.  M.  H. 
Clifford,  late  of  the  Forest  Department,  has  recently 
been  found  among  some  old  papers  in  Dehra. 
According  to  this  note  native  hakims  extract  a kind 
of  oil  from  the  large  velvety  red  mites  {Tetranychus 
sp.)  commonly  known  as  red  spiders  of  Birhhoti  in 
the  North-West  Provinces.  The  oil  is  sold  for 
mediciiral  purposes  at  a high  price,  and  even  the 
insects  themsmves  fetch  as  much  as  a rupee  per 
tola.  It  will  be  interesting  to  learn  if  anything 
further  is  known  of  the  medicinal  virtues  attributed 
to  this  mite.” 
I have  been  searching  through  various  old  records 
to  find  out  the  earliest  reference  to  these  pests,  and 
it  would  appear  that  in  the  year  1868  attention  was 
first  drawn  to  the  subject.  This  date  is  also  con- 
firmed by  enquiries  I have  made  of  these  in  a posi- 
tion to  know  when  visiting  the  various  tea  districts. 
I shall  now  give  you  two  extracts  from  the  Pro- 
ceedings of  the  Agricultural  and  Horticultural  Society 
of  India  for  186'.)  and  1874,  I'espectively. 
I think  there  can  be  no  doubt  that  these  refer 
to  “ red  spider  ” and  ” mosquito  blight,  ” the  black 
spots  of  the  latter  being  at  first  mistaken  for  a 
fungus.  It  is  extremely  probable  that  these  pests 
were  in  existence  for  some  time  prior  to  the  year 
1868,  but  their  dejiredations  must  have  been  on  such 
a small  scale  as  to  prevent  any  serious  notice  being 
taken  of  them.  Here  is  an  extract  dated  20th 
January,  1869  : — 
“ The  Secretary  stated  it  would  probably  be  in 
the  recollection  of  some  of  the  members  present 
that  Dr.  Thomas  Anderson  had  kindly  offered  to 
send  to  the  llev.  M.  J.  Berkley  certain  specimens 
of  tea  leaves  from  Assam  affected  by  a kind  of 
black  smut,  and  of  blighted  tea  leaves  from  Gachar, 
both  which  were  submitted  at  the  monthly  meeting 
in  September  last.  Dr.  Anderson  had  recently  received 
a reply  from  Mr.  Berkley,  of  which  he  now  submit- 
ted the  following  extracts  : — 
“ (1.)  PTom  Gachar  I do  not  find  any  fungus. 
The  spots  are  like  those  which  occur  in  the  genus 
Drpazea,  but  there  is  not  a trace  of  perithecia  and 
they  may  arise  either  from  some  constitutional  con- 
dition or  from  some  peculiarity  of  weather.  In 
many  of  the  spots  the  whole  of  the  parenchyma  has 
vanished,  and  there  is  scarcely  anything  left  in  the 
centre,  except  the  discoloured  cuticle.  'The  spots  in 
this  case  are  quite  transparent  when  held  up  to  the 
light.  (2).  Black  Smut.  I have  in  vain  hunted 
for  perfect  fruit.  The  fungus  belongs,  as  far  as 
external  characters  go,  to  Lcveilles  genus  Asterina 
but  it  is  different  from  any  species  in  my  Her 
barium.  I should  be  glad  to  have  specimens  gathered 
early  in  the  season,  and  then  I may  perhaps  tell 
you  whether  it  is  undescribed  or  whether  it  really 
belongs  to  Asterina.  (3).  One  leaf  has  incipient 
asterina  without  any  parithecia,  and  the  other  has 
been  sprinkled  with  tlie  eggs  of  some  mite,  but  1 
should  not  think  with  the  red  s[)ider  of  our  hot- 
houses. 
“ It  would  be  well  to  get  mo  a fresh  su|)ply  of 
diseased  leaves  from  one  or  more  estates,  and  1 
shall  have  groat  ii'oasuro  in  examining  them,  ll  is 
very  desirable  to  have  furiher  specimens  of  No  I. 
The  fungus  in  No,  2 is  su|)orfi(’iul.  ami  belongs,  as 
1 believe,  to  a genus  very  widely  spreail,  and  requires 
damp  for  its  development.” 
Dr.  Anderson  mentiontd  that  since  he  had  son 
the  loaves  from  Gachar  to  Air.  Berkley  ho  ha 
himself  observed  the  diseased  ionu  of  leaves  fgene 
