Miscellaneous. 451 
MISCELLANEOUS. 
What is the best plan to be adopted for the destruction of the Cossus 
ligniperda and Scolytus destructor? ByC. J. Cox, M.D.* 
Every person at all conversant with merely an outline of gardening, 
must be perfectly aware how seriously trees are sometimes wounded, 
and yet perfectly recover, but that the presence of a few obnoxious 
insects, on the least derangement of the soil, inimical to its habits, 
very speedily causes it to languish, sicken, and die; from the ac- 
curate knowledge we possess of the habits of these insects, and from 
the fact that a tree suffers comparatively nothing from a wound, we 
have carried out, with most perfect success, the following method of 
treatment to remove or destroy the larve of the Cossus. 
Having ascertained that a tree is infested by these insects, and 
knowing by their habits that they are sure to be more or less about 
its base, we ought immediately to commence by removing the soil 
from around it to the depth of at least a foot, scraping off all the old 
and decayed bark above and below ; numerous perforations will appear 
on its removal, these ought to be carefully examined—their character, 
as regards size, colour, or depth; if small and fresh, the insect is 
only a short distance in; it may be destroyed or extracted by inserting 
a piece of wire; if the channel winds so that the wire cannot reach 
it, it must be followed until the larva is killed, as the incision into 
the stem is of less danger than the corrosion of the insect ; having 
cleaned the wounds well by removing all refuse matter, a compost 
of clay and cow manure ought to be inserted. The tree requires 
watching for a week or fortnight to see if any yet remain; their 
exuvie protruding from their channels being sure to lead to their 
detection. To destroy the ova and very young’ larve, yet in the 
crevices of the bark, treat the same as for the Scolytus. 
To destroy the Scolytus, remove all the old infected bark ; the 
entrance to the parent tubes is then exposed; as soon as we find the 
parent channel, and knowing it always proceeds directly upwards, 
and is always superficial, we must, wit the angle of the scraper, cut 
out a small piece of bark; the lateral tubes are thus destroyed with 
the young larve ; the tree must afterwards be washed with a strong 
solution of lime-water, coloured by soot; the tree ought to be 
watched for a fortnight. Should any of the parent insects have 
escaped, the exuvial dust falling from their tubes on the stem will 
lead to their detection. 
By carrying out this plan in our gardens, we have saved the re- 
mainder of our ornamental elm-trees ; and when we consider that 
one man can partially bark eight or ten trees in the day, by means 
of a double-handled scraper, similar to that used by coopers, it has 
been a most inexpensive process ; thus, instead of gazing on a blighted 
foliage and stag-horned trunk, the withered and sickly tinge has 
given place to a most luxurious green and healthy appearance. 
* From a paper read before the Royal Botanical Society of London, 
Aug. 10, 1848. 
ans 
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