34 BULLETIN 1204, tJ. S. DEPARTMENT OF AGMCTJLTtTKE. 
ACREAGE DUSTED PER HOUR. 
The number of acres that can be dusted in an hour by means of 
planes is rather a complicated question, and the information ob- 
tained is only suggestive. As the hoppers used held only about 125 
pounds of poison, frequent landings were necessary. The treatment 
of small areas at a time further restricted the speed. Generally 
speaking, in the work on these two properties, the plane spent from 
6 to 12 minutes in the air at each flight. Much of this time was 
-pent in maneuvering, and a certain amount in going to and from the 
landing field. To avoid loss of time, provisions were made for load- 
ing the hopper fairly quickly when the planes landed, but this opera- 
tion could be greatly expedited by more elaborate loading equipment. 
Counting both flying and ground time, the airplanes averaged 6 or 
7 flights an hour, emptying a hopper of dust during each flight. 
At least 240 acres were being treated per hour. 
Other records based on straightaway flights, with more definite 
efforts for acquiring speed in operation, usually showed between 
400 and 500 acres dusted per hour. Since only a small portion of 
this time is spent in actually delivering the dust, and much is con- 
sumed in going back and forth for new loads, undoubtedly the 
acreage capacity of a plane can be greatly increased with larger 
hoppers constructed to hold approximately the maximum carrying 
capacity of the plane. 
ADVANTAGE OF AIRPLANES AFTER RAINFALL. 
Airplanes are not in the slightest dependent on ground conditions. 
so long as the landing field is solid enough to permit landing and 
taking off, and with a sodded field reasonably well drained this is 
possible almost any time. An interesting illustration of this fact 
developed during the work. The leaf worm infestation became heavy 
about August 25 in many fields on both plantations, and on the 
25th and 26th all infested fields were carefully treated. Just as the 
planes were returning from the last flight on the afternoon of the 
26th a heavy storm came up and it rained about 3 inches in the next 
hour. This caused all of the poison which had just been distributed 
over the cotton fields to be washed from the plants. The worms 
eat at a tremendously rapid rate and a delay of 24 hours in poisoning 
them frequently results in the fields being stripped of foliage. The 
next morning the worms were working actively and the fields were 
so muddy that it would have been impossible to operate any ground 
dusting machines. The landing field was dry enough for airplane 
operation, however, and both planes were put into service to catch 
up witli the infestation. In less than one hour all acreage requiring 
poisoning had been treated and the crops were thus again protected 
from damage. For instance, on Hermione plantation 111 acres 
needed poisoning very badly. These were treated between 11.23 
•i. m. and 12. 01) p. m., or in a period of 40 minutes, using 549 pounds 
of calcium arsenate on the area, or an average of 4.9 pounds per 
acre. This was a rather heavy dosage, but the applications were 
made practically at midday, and the wind velocity was rather high, 
so that it was deemed desirable to use an extra quantity in the 
