THE SEMITROPICAL ARMY WORM. 65 
observed feeding on the eggs of the latter. The cabbage worms were 
between one-quarter and three-eighths of an inch in length at this 
time. 
A FUNGOUS DISEASE. 
Empusa sp. — September 8, 1907, a few Prodenia caterpillars, which 
were found dying of a fungous disease in our rearing cages, were 
referred to the Bureau of Plant Industry for identification of the 
fungus. Mrs. F. \V. Patterson stated that it was a species of Empusa. 
METHODS OF CONTROL. 
The arsenical poisons are effective against this army worm under 
ordinary conditions. Experiments performed at Orlando, Fla., how- 
ever, brought out the fact that Paris green, on account of the frequent 
rains which occur at the height of the principal outbreaks in the 
infested regions of Florida, such as Orlando, is almost ineffective and 
it is therefore necessary to use arsenate of lead. Owing to the 
greater adhesiveness of the latter it remains on the plants when the 
former is washed off. 
Paris green, arsenate of lead, and a special preparation which may 
be called adhesive copper arsenite, were tested, the last by request of 
its inventor. It was used in experiments Xos. 8. 10, and 11. A barrel 
sprayer, fitted with Vermorel nozzle, was used for a number of these 
experiments, but for most of them a knapsack sprayer of fine quality 
was employed. Sweet potatoes were sprayed in every case except in 
experiment Xo. 5, where collards were also sprayed, and the work was 
usually begun between 8 and 10 a. m. in bright sunlight. Spraying 
experiments commenced July 12 and were continued until August 7. 
Experiment Xo. 1. — July 12. infested plants were sprayed with 
a solution of Paris green. 5 ounces, and freshly slaked lime. 5 ounces, 
in 50 gallons of water. The spraying was done in the morning and 
rain fell before noon. The next day when the field was examined 
the larvae were found uninjured and practically no poison remained 
on the leaves. The experiment was therefore a failure. 
Experiment Xo. 2. — July 12, Paris green, 8 ounces, and freshly 
slaked lime, 1 pound to 50 gallons of water, were sprayed the same 
day and with the same results. 
Experiment No, 3. — July 17, Paris green was sprayed as in Xo. 2. 
Again rain fell hard and steadily before noon, with the same results 
as in experiments 1 and 2. 
a This would seem to furnish at least one reason why this Important insert 
has heen ahle to supplant its American cousins such as Pomtia nai>i L.. /'. pro- 
todicc Bdv. & Lec., and /'. monuste L., all of which feed on erucifers and are 
called cabbage huttertiies or M worms. *' 
