CONTROL OF GRAPE-BERRY MOTH. 



25 



first application, but where the second had not been applied slightly- 

 more material was required for this third application than for the 

 second application in adjoining plats. This difference is accounted 

 for by the fact that the material from the second application re- 

 mains on the grapes and overcomes the waxy bloom, thereby allowing 

 quick wetting. 



The following comparisons of single-nozzle, double-nozzle, and 

 spray-guns for use in trailer spraying were made : 



Table X. — Experiments icith single and double nozzles and spray guns for use 



in trailer spraying of grapes. E. Dunning's vineyard, Avon Lake, Ohio, 1918. 



[First spray application for grape-berry moth control, June 19.] 



Plat No. 



Number 

 nozzles 

 per rod. 



Nozzle 

 aper- 

 tures. 



Pressure 



per 

 square 

 inch. 



Time to 

 spray 



150 

 gallons. 



Number 



rows 

 sprayed. 



Percent- 

 age of 

 time 



saved. 



Percent- 

 age of 



material 

 saved. 



1 



1 

 2 



Inches, 

 t 



Pounds. 

 175 

 175 

 200 



Minutes. 

 64 

 50 

 38 



14 

 16 

 16 







21.8 

 40.6 







2 



14.2 



3 



14.2 







1 Spray guns, 1 to each hose line. 



In Table X it is seen that two medium nozzles per rod saved 21 

 per cent in time and 14 per cent in materials as compared with one 

 large nozzle. Spray guns saved 40 per cent in time and used no more 

 material than two nozzles per rod, but an angle at the nozzle end of 

 a rod is a necessity for thorough covering of the grape clusters. The 

 writers believe that for the average vineyard two disk nozzles, at an 

 angle of 45°, to each rod, with ^-inch apertures and a pressure of 

 175 pounds, will be found most satisfactory. 



Materials and labor vary so greatly from season' to season and in 

 local sections that figures as to the cost of spraying are of little value. 

 The statement can be made that an average of about 5 acres of 

 thrifty vineyards can be sprayed by two men with a team in a day 

 and will require from 100 to 250 gallons, averaging 147 gallons 

 (Tables I and II) per acre for the first application, and from 160 to 

 300, with an average of 224 gallons per acre, for the second applica- 

 tion. 



CONCLUSIONS. 



The grape-berry moth has been a more general pest in northern 

 Ohio than in other commercial grape sections because of the follow- 

 ing conditions: (1) Production of the late maturing Catawba va- 

 riety, (2) cultural methods favorable to successful wintering of the 

 insect, (3) harvesting methods which leave the insect in the vine- 

 yards, (4) a grape training system which prevents spray materials 

 from reaching the clusters when applied with set nozzles. 



