SPRAYING AGAINST GRAPE LEAFHOPPER. 7 



EXPERIMENT IN VINEYARD OF MR. J. E. BEATTY, NORTH EAST, PA. 



The vineyard of Mr. J. E. Beatty, North East, Pa., had been badly 

 infested by grape leaf hoppers for several years. As a result of their 

 injury the cane growth of the vines had been greatly reduced and 

 there had been a corresponding reduction in yield of fruit. Thir- 

 teen acres of the worst infested sections of this vineyard were sprayed 

 hi 1911. Unfortunately, the spraying was not commenced until 

 about 15 per cent of the first nymphs to hatch had changed to the 

 winged form. The application was made July 12 and 14, using a 

 gasoline-engine power-spraying outfit with two " trailer' 5 leads of 

 hose (see PL III, fig. 1). A pressure of 175 pounds was maintained 

 and about 250 gallons of liquid were applied per acre. Tobacco 

 extract No. I was used at a dilution of 1 part to 150 parts of water. 

 Tins dilution gave good results, even though a large percentage of 

 the nymphs was in the last molt. Within about three weeks after 

 the application was made the foliage of the unsprayed vines com- 

 menced to turn brown, and as the season advanced new growth at 

 the end of the canes ceased, whereas on the sprayed vines the foliage 

 remained green and the new growth continued to develop until late 

 in the season. The berries were larger and a darker purple in color 

 upon the sprayed vines. When the crop was harvested the fruit 

 from 300 vines in the unsprayed plat and from the same number of 

 vines on the sprayed plat was weighed and showed a gain of 690 

 pounds from the sprayed plat, thus giving an increase of 1,380 

 pounds per acre. This fruit was valued at $0,015 per pound, show- 

 ing a gross cash gain of $20.70 per acre. The cost of spray material 

 and labor of application was as follows : 



Team and driver per day $4. 50 



250 gallons of tobacco extract No. I, diluted spray 1. 41 



Two men handling nozzles 3. 50 



Six acres sprayed per day, cost per acre 2. 74 



Increased cash yield per acre 20. 70 



Cost of material and application 2. 74 



Net cash gain per acre on sprayed vines 17. 96 



EXPERIMENT IN VINEYARD OF MR. D. C. BOSTWICK, NORTH EAST, PA. 



The grape leaf hopper was very numerous in the vineyard of Mr. 

 D. C. Bostwick, North East, Pa., during the summer of 1911. The 

 experiment was undertaken on a block of young vines in the second 

 year of bearing. The vines in this block were quite uniform and 

 carried a heavy crop of fruit. About 15 per cent of the nymphs had 

 transformed to adults when the spray application was made. The 

 spray was applied from July 13 to 15. Three acres were taken in 

 about the middle of the block. One acre on each side of the untreated 



