24 BULLETIN 837, TJ. S. DEPARTMENT OF AGRICULTURE. 



greater than where arsenate of calcium was used alone and less 

 than where arsenate of lead was used alone. 



Summary of Results with Spray Materials. 



Arsenicals. — Arsenate of lead powder at the rate of 1-J pounds to 

 50 gallons proved adequate for commercial control of the grape-berry 

 moth in the average case. Arsenate of calcium proved almost 

 equally as efficient as arsenate of lead when compared on the basis 

 of arsenical content and has the additional advantage of leaving less 

 residue at harvest time. 



Spreaders and adheslves. — Resin fish-oil soap at the rate of 1 

 pound to 50 gallons possessed all the qualities desired and required 

 33 per cent less spray material than laundry soap and 86 per cent 

 less than soft soap, to wet the grape clusters on an equal area of 

 vineyard. 



Spray combinations. — The mixture of arsenate of lead and soap 

 with Bordeaux should be used with care on Catawba and Concord 

 varieties. The Bordeaux mixture should be omitted on the Ives va- 

 riety. Stone lime at the rate of 2 pounds to 50 gallons should be 

 added to the arsenate of lead-soap combination when Bordeaux 

 mixture is omitted. 



Dust mixtures. — The dust mixture of arsenate of lead and hy- 

 drated lime did not adhere to the grape clusters as well as the liquid 

 sprays. The dust material was only partially effective for the con- 

 trol of the grape-berry moth. 



Spray residues. — Objectionable residues do not result when the 

 first and second spray applications are used with care. A spray ap- 

 plication in August with the materials necessary for berry-moth 

 control will leave a residue which will bar the fruit from the basket 

 market. 



COST OF TRAILER SPRAYING. 



Because of the fan training system it was necessary, when spray- 

 ing, to drive between each two rows of grapes. Each rodman sprayed 

 but one side of one row at a time. In the Chautauqua-Erie belt it 

 was found possible for a man to spray both sides of a row as he went, 

 but there appears to be little gain in time by the latter method. In 

 all of the experimental work it was found possible to mix and apply 

 6 tank loads of 150 gallons each or a total of 900 gallons in 9 work- 

 ing hours. This amount of material covered from 3 to 8 acres, de- 

 pending on local conditions, and averaged about 5 acres. About one- 

 half more material was required for the second application than 

 for the first. Where the third application was made on plats that 

 had received the second, the amount was about the same as for the 



