VINEYARD SPRAYING AGAINST ROSE-CHAFER. 63 



tion to this a third plat was sprayed with arsenate of lead and Bor- 

 deaux containing no molasses. In this work it was not possible to 

 detect that the beetles exhibited a greater preference for the foliage 

 or blossom clusters sprayed with the sweetened arsenical, nor was 

 there evidence of a greater benefit from rose-chafer protection on the 

 plats sprayed with the sweetened arsenicals as against the plat 

 sprayed with the unsweetened arsenical. Where the arsenite of lime 

 was applied there was evidence of a slight burning of the tender 

 foliage, which was not apparent where the arsenate of lead was used. 

 During the seasons of 1909 and 1910 the writer used, on adjoining- 

 plats, molasses and arsenate of lead with the Bordeaux mixture, 

 and also arsenate of lead unsweetened and Bordeaux mixture, em- 

 ploying in both cases 5 pounds of arsenate of lead to 50 gallons of 

 the mixture. In none of these experiments was there detected an}^ 

 decided benefit from the presence of the molasses. Keports are per- 

 sistently circulated that good results have been secured by the addi- 

 tion of some sweetening substance, either molasses or glucose, and 

 since the rose-chafers feed upon the flowers and nectaries of grapes 

 and other fruits it is reasonable to suppose that the presence of a 

 sweetened substance in the spray would attract them. The increased 

 expense of the molasses is but slight, and it is suggested that the 

 vineyardist using arsenicals in combating the rose-chafer employ a 

 sweetened arsenical on a portion of his vineyard and compare results 

 with a portion treated with an unsweetened arsenical. Until more 

 data is at hand on this subject the writer, while not wishing to dis- 

 courage the use of a sweetened arsenical against the rose-chafer, feels 

 that the results which have come directly under his observation do 

 not appear to justify the recommendation of its general use. 



TIME TO MAKE THE SPRAY APPLICATIONS. 



In regard to the cost of spray application for the control of this 

 pest, it should be pointed out that the entire cost should not be 

 charged to rose-chafer control, since it is highly desirable that a 

 spray application be made before the blossom-buds expand against 

 the grape-beiTy moth (Polychrosis viteana Fab.), and also for 

 fungous diseases. The later spraying just after blossoming is also 

 necessary against the grape rootworm {Fidia viticida Walsh). No 

 additional spray applications were made on the vineyard of Mr. F. C. 

 Hirt after June 24. Yet there was practically no evidence of feeding 

 by the beetles of the grape rootworm on the treated portion of the 

 vineyard, nor was there any evidence of mildew on these vines, 

 whereas on the untreated check rows there was a large amount of 

 feeding by the grape rootworm beetles, and the clusters of fruit were 

 also very badly mildewed. Hence the evidence secured during the 

 past season indicates that if vineyardists, in regions where the rose- 

 chafers commonly occur in injurious numbers, will resort to a thor- 



