420 JOURNAL OF ECONOMIC ENTOMOLOGY [Vol. 4 



scarcity of the insect in the same locahty for a period of over ten 

 years. 



The remedy used has been arsenate of lead and this has been com- 

 bined with the Bordeaux mixture. Its use has given good results in 

 the hands of most experimenters but there have been failures when 

 the work has been done thoroughly and many of the vineyardists 

 have had similar experiences. At first we were inclined to regard 

 such failures as due to careless and indifferent spraying, believing 

 that the men conducting the spraying either did not apply it thoroughly 

 or applied it at the wrong time, but our experience in connection with 

 a series of cooperative experiments where the work of spraying was 

 carefully watched and which did not give the expected results, indi- 

 cated that some other factor entered into the problem. As it was 

 believed that the beetles migrated from sprayed to unsprayed vines 

 and since no dead beetles could be found under such sprayed vines, we 

 made a careful study of the failure to control the beetles by the ordi- 

 nary spray. 



About an acre of vineyard was sprayed a second time the same day, 

 thus using 200 gallons to the acre and as the vines were not very luxu- 

 riant, almost every leaf was covered with the Bordeaux mixture 

 and arsenate of lead. Sheets placed under the vines had no dead 

 beetles the next morning but the vines were free from beetles where 

 the day before were thousands. Another acre about an eighth of a 

 mile away was sprayed with a mixture of six pounds of arsenate of 

 lead and one gallon of molasses to each 100 gallons of water. The 

 vines were sprayed once, using about 100 gallons of material to the 

 acre. All the foliage was not covered as it is next to impossible to do 

 so with stationary nozzles at one spraying. Sheets placed under the 

 vines had a number of dead beetles the following morning and a few 

 beetles were still feeding on the vines. This plainly was an example, 

 on the one hand, of migration because of a distaste of the material 

 used, and, on the other hand, a feeding on the poison due to its pleasant 

 taste. 



With this clue, during the present season, a large number of brands 

 of arsenate of lead have been used in cage experiments in which both 

 sprayed and unsprayed leaves were in the same cage. With every 

 brand the beetles preferred to feed on the unsprayed fohage showing 

 very plainly that they dishke arsenate of lead. Other cages where 

 the poison was added to either glucose or molasses showed the beetles 

 feeding greedily on the sweet material. This was also noticeable in 

 the field experiments where the beetles were observed passing to those 

 parts of the vine that were covered with the sweetened poison, thus 

 plainly showing their tastes. Moreover, vineyards seriously infested 



