26 BULLETIN 831, U. S. DEPARTMENT OF AGRICULTURE. 



Spray schedule. — The combination of first and second spray appli- 

 cations is adequate for control on the principal varieties of grapes 

 grown in northern Ohio and when carefully applied leaves the fruit 

 suitable for the basket market. 



Spray materials. — A combination of arsenate of lead powder 1| 

 pounds to 50 gallons and resin fish-oil soap 1 pound to 50 gallons, in 

 Bordeaux mixture or with stone lime 2 pounds to 50 gallons, may be 

 used for spraying Concords and Catawbas. Copper sulphate should 

 not be used in the above mixture for Ives variety. Arsenate of cal- 

 cium, commercial powder, proved almost as efficient as arsenate of 

 lead for grape-berry moth control. Dust mixtures do not adhere to 

 the grape berries as well as liquid sprays but may be used on small 

 home grape arbors if applied frequently. 



Spray residues. — The grapes will be practically free from spray 

 residue if the schedule recommended is used according to directions. 



Spray method. — The trailer method only was used, and a trailer 

 provided with a short rod and two angle nozzles proved most satis- 

 factory in most vineyards. 



RECOMMENDATIONS. 



When possible, vineyards should be placed in condition for winter 

 at the end of the cultivation season in July and left without further 

 cultivation until spring ; this practice is designed to increase the win- 

 ter mortality of the grape-berry moth pupae. 



Number of spray applications. — For general practice for grape- 

 berry moth control in northern Ohio two spray applications should 

 be made. 



Time. — The first application should begin 3 to 5 days after grapes 

 set and the second should begin when the grapes touch in the clusters. 

 This second application will usually come 3 to 4 weeks after the first. 



Method. — Where the berry moth is a major pest the trailer method 

 of spraying is the only one that will give complete control. 



Materials. — Arsenate of lead, at the rate of \\ pounds of powder 

 or 3 pounds of paste to 50 gallons, as the active killing agent, with 

 resin fish-oil soap, at the rate of 1 pound to 50 gallons, for a spreader 

 and adhesive, used either in Bordeaux mixture or with 2 pounds of 

 freshly slaked lime to each 50 gallons, has proved the most consistent 

 combination tried. Bordeaux mixture should not be used on the 

 Ives variety of grapes in northern Ohio because of the danger of 

 injury to the foliage. Amounts of material should be great enough 

 to allow the covering of all clusters with a thin, smooth film of spray 

 material. 



