86 JOURNAL OF ECONOMIC ENTOMOLOGY [Vol. 15 



Mr. J. S. HousER. Fifty-three yards from the grove, and the dust 

 covered the windward and leeward side as well. I might have said that 

 the wind was blowing at the rate of eight to eleven miles an hour. The 

 grove was three hundred and twenty -five feet wide. 



Mr. F. C. Craighead. How far beyond the grove did the poison 

 extend ? 



Mr. J. S. Houser. Particles carried from five to eight hundred 

 feet beyond, but most of it settled in the grove. 



Mr. F. C. Craighead. With one application can you cover a strip 

 five hundred feet wide'" 



Mr. J. S. Houser. Three hundred and twenty-five feet — and then 

 some drifted on over. The farthest distance of drift I should say was 

 perhaps one thousand feet. 



Mr. W. C. O'Kane. I want to ask whether there were any indications 

 that any of the caterpillars died frorn the wilt disease. I have seen 

 heav>' infestations by the maple worm enormously reduced inside of 

 48 hours by this disease. The conditions of infestation and the heavy 

 defoliation of the trees as shown on the slides indicate conditions that 

 would be favorable for an outbreak of the wilt disease. 



Mr. J. S. Houser. I have no evidence that this disease was present 

 in this case. An examination of caterpillars of the same species on trees 

 nearby that were not sprayed showed that they were perfectly healthy, 

 although the conditions as to defoliation were the same. 



Secretary A. F. Burgess: I am very glad to have heard this paper. 

 Last stmimer Mr. Houser invited me to witness the test, but it had to be 

 started a few days earlier than was planned, and I did not have sufficient 

 time so that I could be present. The information given is exceedingly 

 interesting, but we should remember that it was carried on under con- 

 ditions which seem to be extremely favorable for aeroplane work. The 

 ground on which this small area of catalpa trees were growing, was very 

 level, and there were many places nearby where a perfect landing by an 

 aeroplane could be made. Most forest conditions are not as favorable. 

 The weather was apparently favorable, while on large scale spraying 

 operations much adverse weather conditions would probably be encoun- 

 tered. This is not a criticism of the experiments, although I do not 

 believe results similar to these can be duplicated under all woodland 

 conditions. In the gipsy moth work where a large amount of woodland 

 spra^dng is done, the countr>^ is rough and uneven and I believe it very 

 doubtful whether similar results could be secured. The statement made 

 by Mr. Houser concerning the spraying of pasture and com, is very 

 interesting. I do not believe wholesale dusting of this type could be 

 carried on without encountering many complaints from owners of 



