128 OHIO EXPERIMENT STATION: MONTHLY BULLETIN 



After passing the winter in the soil in the pupal stage, the 

 moths appear well after the foliage is formed and deposit their 

 eggs. Within a short time the eggs hatch and the caterpillars 

 begin feeding. After reaching maturity they pass to the soil and 

 change to the pupal stage, which in turn gives rise to another 

 generation of moths. 



About a month is required for the insect to pass through the 

 four stages and during normal seasons, it is believed there are but 

 two generations of the insect each year in Ohio, but during the sea- 

 son of 1921, three full broods appeared. 



THE USE OF THE AIRPLANE IN DISTRIBUTING POISON 

 ON TALL TREES 



Early in the spring of 1921, Mr. C. R. Neillie, now acting City 

 Forester of Cleveland, suggested to the writer that the airplane 

 might be used advantageously as a means of distributing poison on 

 tall trees and asked that if the opportunity presented itself that the 

 method be given a trial. 



Overtures were made to the Air Service of the Federal War 

 Department for co-operation in the project and the arrangements 

 were well under way when the outbreak of catalpa sphinx appeared 

 at Troy and offered an immediate and convenient opportunity for 

 making the experiment. 



Through the hearty co-operation of the officials of McCook 

 Field, Dayton, Ohio, specific plans were made for conducting the 

 test. And in this connection the writer wishes to place on record 

 the appreciation of the Experiment Station to those officials most 

 concerned in the project, Major T. H. Bane, Director of McCook 

 Field; Maj. H. S. Martin, Chief of the Engineering Division, and 

 his assistant, Mr. M. Dormoy, who designed the hopper and 

 operated it during the trials ; Lieut. J. A. Macready, chief of the 

 flying section, who piloted the plane ; and Capt. A. W. Stevens, who 

 photographed the dusting plane in action. 



The value of the photographic record obtained by Captain 

 Stevens scarcely can be overestimated, since it depicts in a manner 

 beyond the power t>f the printed or spoken word to describe just 

 what happened when the poison powder was released from the 

 plane. 



DESCRIPTION OF THE CATALPA GROVE UNDER TREATMENT 



The grove under treatment belonged to H. B. Carver and was 

 located about 4 miles west of Troy, Ohio. It was a level, rectangu- 

 lar plot 800 x 325 feet and contained about six acres. The trees, 



