February, '22] DE LONG: GRAPE LEAF hopper control 87 



pastures. I hope further experiments with aeroplanes will be continued. 

 It is a good line to follow up, but there will be many practical difficulties 

 to overcome before aeroplane spraying will be brought to a state of per- 

 fection where it will be practical in rough forest areas. 



In regard to the wilt disease, from the amount of defoliation of these 

 catalpa trees and the rapid death of the caterpillars, I have a suspicion 

 that some wilt disease was present. 



Mr. J. S. HousER. The catalpa sphinx is a rather watery, flabby 

 caterpillar and begins to decay very soon after death. This, I think, 

 explains the reason why the breakdown of the caterpillars was so rapid. 

 I believe it was the spraying that was responsible for their death. 



Mr. William Moore. What was the material you used? 



Mr. J. S. Houser. Powdered arsenate of lead. 



Mr. H. a. Gossard. I was present at the time this work was con- 

 ducted, and I would say, regarding the question of wilt, that these cater- 

 pillars were not starving at all. There was abundant young foliage on 

 the trees the day the dusting was done. We climbed those trees after 

 the work was done, to the tops of them, and branches were brought 

 down. I really didn't do the climbing but I received some of the branches 

 that were brought down, and the amount of dust that was on them and 

 on everything in the grove made us expect that those fellows would 

 begin to wilt — but not with wilt disease. There wasn't a sign, the day 

 I was there, of any disease with those caterpillars. They were there in 

 abundance and were healthy and were feeding at a great rate. Three 

 days later, Mr. Houser made a report that about ninety-nine per cent, 

 of them was dead. 



I think these questions are entirely proper but I don't think anyone 

 who was present and saw the work done, would have any suspicion at 

 all that a bacterial disease attacked those caterpillars. It was some- 

 thing else. 



President George A. Dean. The next paper is by Mr. D. M. De 

 Long. 



THE BOOMINOZZLE SYSTEM AND THE TRACTION DUSTER 

 AS FACTORS IN GRAPE LEAF HOPPER CONTROL 



By D. M. DeLong, Ohio State University 



The Grape Leaf hopper (Erythroneura comes Say) has been a very 

 serious pest in the Erie-Chautauqua grape area along the southeastern 

 shore of Lake Erie for many years. The attacks of these minute insects 

 during several successive siimmers may be so inconspicuous that the 

 growers may be inclined to regard the pest as a factor of diminishing 

 importance in grape growing, and they are always hopeful that it will 



