THE SKMITHOPUWL ARMY WOH.Af. 65 



observed feeding on the eggs of the hitter." The cabbage worms were 

 between one-quai't(M- and three-eighths of an inch in length at tliis 

 time. 



A FUNGOUS DISEASE. 



EmpuHCi sp. — September 8, 1907, a few Prodenia caterpillars, which 

 were found dying of a fimgoiis disease in our rearing cages, were 

 referred to the lUireau of Phint Industry for identification of the 

 fungus. Mrs. F. W. T*atterson stated that it was a species of Empusa.. 



METHODS OF CONTROL. 



The arsenical poisons are etiective against this army Avorm under 

 ordinary conditions. Experiments performed at Orlando. Fla., how- 

 ever, brought out the fact that Paris green, on account of tlie 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 Verniorel nozzle, was used for a number of these 

 experiments, but for most of them a knaj)sack 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. 



Experhiund Xo. 1. — July 12, infested plants were spraj^ed with a 

 solution of Paris green, 5 ounces, and fresh air-slaked lime, o 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. 



Experhneiit 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 Xo. 3. — July 17. Paris green was sprayed as in Xo. 2. 

 Again rain fell hard and steadily before noon, with the same i-esults 

 as in experiments 1 and 2. 



"This would seem to fiiniish at least one reason why this Iniporlant insoct 

 has been able to sni)iilant its American consins snch as f'oiitia nniii L., /'. />/•<*- 

 iodicc P.(lv. iS: Lee, and /'. iiioinistc 1.., all of which feed (»n crucifers and are 

 called cabbafif* biittertiies or " worms.' 

 66— V 



