Diseases of the Poppy Plant,
PAPAVER
somniferum.
CULTIVATION
Diseases.
Peronospora.
"(h) Sporocybe.—A genus affecting the decaying parts of plants, and
usually forming a blackish stratum thereon. The species have erect,
simple, or branched peduncles, terminating in a capitate head studded
with spores. The species found on the poppy much resembles the S.
bulbosa, chiefly distinguished by its rigid, erect peduncles, slightly inflated
at the base, and ending in a globose head of brownish-coloured spores.
As affecting only the dead organs of the poppy, it is, of course, quite
innocuous,
alluded to here as being of common occurrence on the
decaying parts.
" (j) Macrosporium.—A genus affecting similar habitats to the preced-
ing, and distinguished from it by its large, transversely and ver tically
s e p t a t e s p o r e s . S p e c i e s o f t h i s g e n u s a r e v e r y a b u n d a n t i n I n d i a , b u t a r e
perfectly innocuous to vegetable life, springing up only on the rotten or
decaying parts of plants. The spores of this and the preceding genus are
among the most abundant of the organic products found in the exami
-ation of the air at Calcutta.
" (i) Helm int hosporium.—The species of this rather extensive genus of
dark threaded moulds affect rotten wood and the decaying parts of plants
generally. They have a gelatinous or indistinct mycelium, from which
spring up erect, rigid, fertile filaments, terminating in large less or more
elongated, often club-shaped, many-septate spores of a brownish-black
colour. The species occurring on the poppy has erect septate filaments,
with oblong and club shaped, 6 to 10 septate spores.
the Economic Products of India.
59
certain further remarks regarding poppy mould and other fungi seen on
the opium plant.
" From these personal observations I was thus rather prepared for the
periodicity in the mould attack, of which we are afforded unmistakable
evidence in the Gya and Tehta returns, for the last quarter of a century
or so. In conjunction with my own observations, these crop statistics
indicate intervals of from three to four seasons in the appearance of the
mould in a more or less severe blight form. Admitting, then, the opera
-tions of a law of periodicity, I would explain the apparent triennial or
quadrennial recurrence 0f m o u l d i n a v i r u l e n t f o r m .t
h u s : —
F i r s t ,I
a m
led to assume, on a careful reconsideration of the results of all my obser
-vations and experiments, that the degree of virulence, or at least the
particular form–i . e
. , t h ed
r y
, o r -h
u m i d ,a
n d
r o t t i n g — i st
o a c e r t a i n
extent modified by prevailing atmospherical conditions during the latter
stages of the mould's maturity, which, as a rule, is from about the close of
February until the middle of March. Again, however, in seasons when
the mould has attained a very extensive development on the crops, it, irre-
-spective of the weather, tends to induce certain obscure chemical changes
in the cell-contents and juices of its foster-parent, which would appear to
entail an active resumption of the vegetative function and the complete
abeyance of the reproductive."
Some of the moulds observed by Mr. Scott are common Saprophytes,
by no means confined to the Opium plant. It may, however, be found of
some service to complete very briefly his enumeration.
Helminthos-
porium,
Sporocybe.
Macros-
porium.
" (k) Cladosporium.—A genus affecting both decaying animal and vege-
table substances, and found in nearly every habitable part of the globe.
C. herbarum is the species found on the poppy, forming thereon olive-
green patches, which consist of jointed microscopic threads more or less
varicose, simple, or branched, and bearing on their sides oblong or elliptic
spores of an olive-colour, with one or two transverse divisions. It is very
common on the older gummy exudations of the poppy, and also frequent
on the injured capsules ; indeed, on all injured or decaying parts.
" (1) Aspergillus.—A genus found everywhere on decaying substances
and accelerating decomposition. A well-known species is the A glaucus,
Cladorporium.
Aspergillus.