M. DRANERT ON DISEASE IN THE SUGAR-CANE. 
15 
carried on in that province, and is esteemed profitable ; whereas, 
on the contrary, in the more northerly and hot province of Eio 
Janeiro and the neighbouring departments, coffee is preferred. 
In Bahia, the most important part of Brazil as regards sugar, 
where the occupiers of the coast devote themselves almost exclu- 
sively to the cultivation of the sugar-cane, the disease has ap- 
peared for the last six years in the most threatening form. At 
JSTazareth, near the town of Bahia, the harvest for three years 
has been almost annihilated by the malady ; and it has since spread 
to the northern parts of the province. Repeated inquiries, under 
the direction of the Government, have at present led to no re- 
sult. ]N"ew varieties have indeed been introduced, and amongst 
them one from Salangore, very rich in juice ; this, however, has 
been by no means entirely exempt from the malady, which, not- 
withstanding the extraordinary drought (from September 1868 to 
the end of January 1869), begins already to be established. 
My observations of this malady were directed especially to the 
investigation of the insects which live on the sugar-cane, since cer- 
tain commissions, and even men of science, have given it as their 
opinion that it is due to their agency. It was recorded as the re- 
sult of a commission of inquiry in Santa Catharina, that a caterpillar 
known under the name of "borer" was the cause of the disease. 
I have occasionally found it, as well as the pupa, in the stem of 
the cane. The caterpillar eats its way from without into the stem 
and forms bores. Large holes also are formed in the uppermost 
joints, by which the vegetation is impeded ; and this is equally the 
case when the young cane is perforated by the insect. The last- 
mentioned cavities, however, are far more rare ; and the bores from 
about one-eighth to one-sixth of an inch in diameter in nearly 
mature strong canes, though frequent enough, do not impede the 
vegetation, though, through the admission of air and the conse- 
quent oxidation, the surrounding layers of cells become red and 
the quality of the sugar-sap is somewhat impaired. In spite of 
all, the sugar-cane thus affected yields good sugar ; and intelligent 
cultivators have discovered a different indication of the disease. 
Another insect, which is sometimes found abundantly between 
the sheaths and the stem, is a female Coccus, whose habits, as far 
as my observations go, agree with those of its allies. Allowing 
that it robs both leaves and stem of a quantity of juice, it yet ap- 
pears that the injury is too slight to prevent the development of 
sugar, added to which the presence of the Cocc-us is not the ne- 
YOL, III. E 
