58 



DECIDUOUS FRUIT INSECTS AND INSECTICIDES. 



Table XXIV. — Spray formulas and dates of application against larvse of the grape-berry 

 moth. Vineyard of Mr. W. S. Wheeler, North East, Pa., 1908. 



Plat 

 No. 



Spray formula. 



Number 

 of spray 

 applica- 

 tions. 



Date of application. 



I 



II.... 



Three pounds arsenate of lead and 2 pounds resin-fish-oil to 50 



gallons of Bordeaux mixture. 

 do 



2 



3 

 2 



1 



June 4, 18. 



June 4. 18; July 6. 

 June 19; July 6. 



III... 



do 



IV... 



do 



Va-b. 



Unsprayed. 





The same spraying machine and the same nozzle arrangement 

 were used as in 1907. The pressure maintained was from 100 to 125 

 pounds. About 100 gallons of spray were applied per acre. The 

 first application was made June 4, just before the blossom buds 

 opened. A double application was made at this date; that is, as 

 soon as the plats had been sprayed once the same plats were gone 

 over again. Only Plats I and II were sprayed at this date. On 

 June 18, just after blossoming, when the berries were about the size of 

 buckshot (PL VIII, fig. 1), all four of the plats were given a double 

 spraying. About 100 gallons of spray were used at each application 

 and a pressure of from 100 to 125 pounds was maintained. Plat II 

 received a third application July 6. This also was a double applica- 

 tion. In making these double applications the vines were covered 

 very thoroughly by the spray. 



As in the previous season the infestation proved to be widely vari- 

 able, rendering it impossible to make a comparison of the value of the 

 variation in the number of applications made to the different plats. 

 The infestation was distributed in about the same general manner as 

 in the previous year. Plat I, on the south side of the section, was 

 the most heavily infested, the infestation gradually decreasing in the 

 other plats toward the north side of the vineyard. Counts were 

 made on 25 vines in each of the check plats and also in each of the 

 sprayed plats to show the progress of infestation for the first and 

 second broods. (See Table XXV, showing count of infested berries 

 for 1908.) 



Table XXV. — Progress of infestation of fruit by larvse of the grape-berry moth in experi- 

 mental plats. Vineyard of Mr . W. S. Wheeler, North East, Pa., 1908. 



FIRST COUNT OF INFESTED BERRIES, MADE ON AUGUST 3, 4. 



Plat No. 



Date of spray application. 



Spray formula. 



Number 

 of appli- 

 cations. 



Number 

 of vines 

 exam- 

 ined. 



Number 

 of in- 

 fested 



berries. 



I 



June 4, 18 



5_5_3_2_50 



2 

 3 

 2 

 1 



25 

 25 

 25 



25 



28 



II . 



June 4, 18; July 6 



June 19; July 6 



5_5_3_2-50 



25 



Ill 



5_5_3_2-50 



21 



IV.. 





5_5_3_2_50 



31 











