56 
the plat on which it was burned in the fall by a plantation roadway 
about 20 feet wide. Needless to state, these conditions were not of 
the best for the experiments. It would have been better if each 
plat had been comparatively isolated from other plats of cane so 
that there would have been no danger of the insects going from one 
plat to another. 
It will be noted that the infestation at the end of May was almost 
negligible in all plats, but even then the least injury was in the plat 
where trash was plowed under in the spring. By October 28 the 
most conspicuous injury ("dead hearts" and large plants killed) 
was small, but the difference between the plats subjected to different 
treatments is notable. Again, the smallest number of killed plants 
(3) was found in the plat where trash was left on the field in the 
winter and plowed under in the spring. Fall burning gave as many 
as 38 plants killed. In the plats where the trash was raked to the 
headland in the spring, and where it was burned in the spring, there 
were 12 and 6 dead plants, respectively — several times more than 
where the trash was plowed under in the spring. A few days later, 
when the cane was cut, a careful examination was made of over 600 
canes in each plat. Where the trash was burned in the fall the 
infestation was nearly 84 per cent, but where the trash was plowed 
under in the spring it was only about 46 per cent. The experiments 
in raking the trash to the headland, and in burning it in the spring, 
gave about 65 and 69 per cent, respectively. From these experi- 
ments spring burning seems to be better than fall burning, and plow- 
ing the trash under in the spring better than either. (PI. VIII, fig. 
2.) Raking the trash to the headland, for some unknown reason, 
did not give as good results in 1914 as it did in 1913. 
Extensive experiments on plantations in Louisiana were carried 
on in 1915, 1916, and 1917. During 1915 and 1916 the results were 
negative, the infestation being about the same on fields where trash 
was not burned as where it was burned. The fields not burned were 
usually in the midst of other fields Avhich had been burned over. 
Yet in 1916, when the trash was not burned except on one field at 
Audubon Park, the infestation was much lower there than anywhere 
else in the State, with the exception of two places which had been 
flooded. The average infestation in Louisiana for 1916 was 75.5 per 
cent, while the infestation at Audubon Park was only 38.3 per cent. 
The reason for the difference between the results on plantations 
and those at Audubon Park was not understood until it was sug- 
gested in 1917 by Mr. W7 G. Taggart that the relative isolation of 
the fields at Audubon Park had prevented the reinfestation of the 
unburned fields by moths flying from other plantations. This ex- 
planation seems to be correct, and the latest results tend to confirm 
it. The average infestation in Louisiana in 1917 was 45.8 per cent, 
