THE SUGAR-CAFE MOTH BORER. 43 
hearts" had not been cut out at that place. Individual fields at 
Angola ran from 6 to 85 per cent, and at Port Allen from 9 to 
94 per cent. 
It is possible that the different fields at Angola did not all re- 
ceive exactly the same treatment as to cutting out the " dead hearts," 
especially as the plantation is divided into a number of farms or sec- 
tions, each of which has its separate manager. As far as the 
authors could ascertain, however, the treatment had been uniform 
over the whole plantation. 
It Was the opinion of several of the farm managers that cutting 
out the " dead hearts " would not be practicable on a plantation 
where free convict labor is not available. 
Moore (104) records the collection of 15,285,960 larvse and pupse 
of the moth borer on 17 estates in Demerara, British Guiana, in 1912, 
and 13,632,655 in 1911. He then remarks : 
The effect upon the pest of all this terrific slaughter has not as yet been very 
marked, but will increase more and more rapidly if the destruction be kept on 
persistently, systematically, and relentlessly. The insect propagates at such a 
very rapid pace, in spite of the counter-activity of a variety of natural enemies, 
and in spite of whatever may be the weather conditions, when its seasons 
come round, that to overtake it and bring it under proper control must needs 
be a rather long undertaking. 
POISONING YOUNG PLANTS. 
By covering the young plants with an arsenical in powdered form, 
which was suggested by the junior author, it was hoped to present 
a poisoned leaf surface to the first young borers of the year. Before 
gnawing into the plants the newly emerged larvae feed among the 
leaf whorls for a limited time. It was thought that if they could 
then be poisoned much damage later on could be prevented. 
A small preliminary experiment gave what seemed to be promis- 
ing results, and in 1916 a large plantation experiment was planned. 
Fields on a typical plantation were poisoned one, two, and three 
times, powdered arsenate of lead being used, and the applications 
being made at many different dates in the spring. After nearly 
every application, however, there was a heavy rain, and the follow- 
ing fall no benefit could be observed. About 2 pounds of poison 
per acre were applied, a special horse machine being used. 
The experience gained in 1916 had proved that the machine, 
which was designed for cotton, was not well adapted to sugar-cane 
fields. In 1917 the framework was strengthened and a gasoline en- 
gine added. This gave a much more uniform distribution of the 
poison, and an application of 2 pounds per acre covered the plants 
rather thoroughly. One man and a 2-horse team with this machine 
could cover 35 acres per day at a total cost for labor and material of 
