February 7, 1903. 
THE GARDENING WORLD 
V 
Gleanings from the World of Science. * 
The undermentioned subjects were discussed at the meeting of 
the Scientific Committee ot the Royal Horticultural Society on 
the 27th ult : — 
Peas Attacked by Grubs .—Mr. Saunders gave the following 
report upon the specimens brought by Mr. Raker to the last meet¬ 
ing :—“ I have examined a considerable number of the damaged 
Reas exhibited at the last meeting of the Scientific Committee, 
and I cannot say definitely by what insect they have been injured. 
The weevil (Bruchus Pisi) certainly is not the culprit. Many of 
them appear to me to have been attacked by the ‘ Pea moth ’ 
(Grapholitha pisana), but I cannot find any trace of the insect; 
but that is not to be wondered at, as the moth lays her eggs on 
the pods when they are quite young, whence the little caterpillars 
make their way into the pods and feed on the Peas. When full 
grown they fall to the ground, and become chrysalides in the soil. 
A few of the Peas were attacked by mites, which were feeding on 
them in considerable numbers ; and it is possible that they were 
the sole cause of the mischief ; but I think not, or I should have 
found them in a larger proportion of the Peas. The mites, no 
doubt, only attacked the Peas after they had been placed in 
store, and any receptacle in which they were placed should be 
thoroughly cleansed ; scalding is perhaps the most satisfactory 
method, if it be practicable. If any Peas attacked by mites were 
sown no harm would be done. Some I examined would not have 
germinated, but the pest would not spread in the ground. If the 
Peas were injured by the caterpillars I have mentioned, it would 
be well, if not too late, to bury the top 3in. of soil on which they 
grew as deeply as possible, so as to prevent the moths from 
leaving the chrysaliles later on. The mites had appeared, no 
doubt, after harvesting.” 
TVsevilled Peas. —Mr. A. Sutton sent specimens for comparison 
with those brought by Mr. Baker, in which the hole was quite 
irregular ins shape, whereas it is perfectly circular if caused by 
the weevil.—“ In further ’'eply to your letter of the 13th inst., 
I now T send you three samples of weevilled Peas, as a comparison 
between these and the maggoty seeds you sent me, which may be 
of interest to yourself, and possibly also to the Committee on 
Tuesday. Sample No. 1 are English grown early round Peas of 
harvest 1901, with a few of harvest 1900. Both these seasons 
were exceptionally hot and dry, and it is only in such seasons 
that we find English-grown Peas at all weevilled. Broad Beans, 
on the other hand, are much more often attacked by these insects 
than Peas, but in such a wet, cold summer as the last, the damage 
is very slight indeed.- In 1900 and 1901 a large quantity of 
Beans were badly weevilled. Sample No. 2 is a sample of 
“wrinkled” Peas “Champion of England,” Canadian grown, of 
harvest 1900. These you will find also show the distinct clean 
circular opening made by the weevil in its escape from the seed. 
As I said in my last letter, I niever recollect seeing a sample of 
English grown wrinkled Peas weevilled. No. 3 is a sample of 
French Sugar Peas, also weevilled, and you will find the dead 
insects inside some of these seeds. These are of harvest 1901.” 
Sclerotium on Lilium Flower Stalks. —Dr. Cooke reported on 
the specimen submitted at the last meeting by Mr. Holmes, 
having a black sclerotium on the flower stalks of Lilium can- 
didum : —“ In so far as a sclerotium can be determined appears 
to be the s;me as one which is common on the stems of Hera- 
cleum and other Umbelliferae, and I think was called in olden 
time Sclerotium durum, when it was also recognised (see Hand¬ 
book, page 601) as the origin of the mould Botrvtis, or Polyactis 
cinerea. Berkeley described a mould on Lily stems as Ovularia 
elliptica, for which I afterwards suggested Botrvtis elliptica. 
Marshall Ward, in his paper on Lily disease, seems to have made 
acquaintance with the same mould, which he simply calls 
Botrytis. Massee recently in Journ. R.H.S. figures the mould 
under the name of Botrytis cinerea. Possibly there is only one 
mould, and that one the old Botrytis cinerea. But now, in 
latter days, this mould is regarded as the conidia of a Peziza, 
under the name of Sclerotinia fuckeliana, and perhaps some 
others; at any rate, the little black Sclerotium, the mould, and 
the Peziza are regarded as phases or conditions of the same 
fungus.” 
Dead Horse Chestnut Trees .—Dr. Cooke also communicated the 
following report:—“ Since the last meeting of committee I have 
been consulted as to the death of some old Horse Chestnut trees 
in Greenwich Park, which has been caused it is confidently 
affirmed by a fungus which appears externally on the bark, and, 
internally, in a plentiful mycelium between the bark and wood. 
The species credited with this destruction is Stereum purpureum, 
although, as far as I am aware, neither Hartig, nor any other or 
the German authorities on the parasites of forest trees, have 
mentioned this species as suspected of causing disease or death. 
It is generally recognised that the yellow Stereum hirsutum, 
which is so common on all dead wood as a saprophyte, is capable 
also of becoming parasite, and, entering by wounds in the bark, 
causes destruction of living trees. Hence it is not so improbable 
that Stereum purpurem may also be capable of becoming a para¬ 
site. Another phase of this subject is interesting. Not long 
since it was brought to the notice of this committee that a paper 
had been published which contended that this same fungus was 
the cause of ‘ silver leaf ’ in stone fruit trees.” 
Araucaria Bidwilli, Cone.- —Mr. F. Bull, Southport, sent a cone 
of this tree, which is the first it has borne in the Botanic Gardens. 
The tree is about 40ft. in height. Dr. Masters observes that it 
fruited at Kew in 1873 (see “ Gardeners’ Chronicle,” 1873, 
page 561, fig. 73). As the tree requires a great deal of space, it 
is not likely that there are many specimens outside botanic 
gardens. The seeds are eaten by the natives of Australia. 
Campanula rotundifolia, diseased. —Mr. Worsdell exhibited 
specimens in which the flower-buds were attacked by Cecidomvia 
Campanulae, and presented a swollen appearance. 
Pelargonium stipules, use of. —Mr. Davidson, Fanners, Wick¬ 
ham Bishops, Essex, described an experience indicating a special 
use of these organs : “ Some time ago I was struck with the 
‘ nursing ’ properties of the stipules of Pelargonia, which, when 
grown cold in winter, lose their leaves. If, for the sake of tidi¬ 
ness, the withered stipules are also removed, the buds are very 
slow to break in spring ; but if the stipules are left on, the buds 
break much more readily, a fact wdiich I found to be due to their 
holding moisture, and thus softening the skin. Darwin has 
observed that stipules sometimes serve to hold water.” 
Club-root in Crucif erae. —In reply to a question as to remedies, 
Mr. Massee wrote as follows : “ The germs are hungered out, if 
the soil is kept free from cruciferous plants—cultivated and wild 
—for four years ; their exit being hastened by the use of lime. 
As it would be at least inconvenient to' cease growing ‘ greens 1 
for such an extended period, the following jdan might be 
adopted : As much quicklime as is compatible with the health, 
growth of Turnips, Sprouts, etc., should be intimately mixed 
with the soil to the depth of 6in. to 8in. Just now is the time 
for this, as the germs will soon begin to be on the run. If gas 
lime is used, a layer, about lin. thick, sprinkled on the surface 
should remain for four weeks, and then be pointed into the 
upper 6in. of soil. No planting should be attempted until after 
the gas lime has been on the 'soil for at least six weeks. The 
great bulk of plants are inoculated when quite seedlings, and 
those that escape for the first six weeks of their existence do 
not, as a rule, become diseased when planted in infected soil.” 
Mr. Baker added some interesting remarks upon his experi¬ 
ence. He said that a badly infected soil should have all cruci¬ 
ferous plants rigidly excluded for four years, and Shepherd’s 
Purse, which is very liable to be attacked, should be entirely 
weeded out. The fungus could not cross a narrow path, but 
could easily be transmitted by garden instruments, or by the 
sole of boots. Superphosphates were rather favourable to the 
growth of the fungus, whereas basic, slag was less so. Mr. 
TV orsley had found gas lime to have been quite effective. 
Ismene calatliina, bulb germinating. —Mr. Worsley observed 
that in the germination of the seeds of this plant, before any 
leaf growth takes place, it forms a bulb and continually loses 
moisture, so that its weight diminishes from that of the seed 
to the amount of 75 per cent. ; so that while ten seeds weigh 
10oz., it requires forty-four of the small bulblets to weigh that 
amount. Besides water, it is known that all seeds lose weight, 
as carbon is lost in respiration, which generates energy required 
for vital processes displayed in growth. 
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