38 BULLETIN 550, U. S. DEPARTMENT OF AGEICULTUEE. 



with "set nozzles" instead of with "trailers/' furnishes on the aver- 

 age only a partially satisfactory measure, while complete substitution 

 of "set nozzles" for "trailers" is entirely unsatisfactory. 



Spray Combination 



A combination of sprays may be made, to control, besides the berry 

 moth, practically all other important enemies of the grape in this 

 region — the grape rootworm, the grape leafhopper, and the powdery 

 mildew. These spraying recommendations for the control of enemies 

 of the grape other than the grape-berry moth are based on recommen- 

 dations of other investigators, 1 and were employed incidentally in 

 connection with the berry-moth experiments. 



The time of the first spray application for berry moth, just after 

 the grape blossoms fall, during the seasons of 1914, 1915, and 1916, 

 has been from 2 to 4 days before the appearance of the rootworm 

 beetles. Without change of time or mixture this application is 

 effective against the rootworm also. If this application is intended 

 as rootworm control also, care should be taken to cover the upper 

 surface of the foliage, for unless extra attention is given to this it 

 is apt to be done less effectively with "trailers" than with "set 

 nozzles." In exceptional instances an extra application for root- 

 worm control may be necessary. This combination must not be 

 attempted if it is desired to add molasses or sugar to the rootworm 

 spray, as mixtures containing sugar are very soluble and wash off 

 the vines readily. Furthermore, a combination of sugar with Bor- 

 deaux mixture is apt to burn foliage. 



The second berry-moth spray, applied when the berries are just 

 touching, may be made effective also against the grape leafhopper 

 by the addition of nicotine sulphate (40 per cent) at the rate of 1-1,600 

 (| pint to 50 gallons.) 



By the addition of Bordeaux mixture in these two applications, 

 powdery mildew also can be controlled. These two applications of 

 Bordeaux will be useful against black rot and downy mildew also, 

 where these occur, although an additional earlier spray will be 

 necessary for the control of these diseases. 



Cost. 



The cost of spraying material and labor required to control the 

 grape-be rry moth, if applied to control the berry moth alone, ,is 

 about $5 per acre. In computing this cost it is assumed that an 

 average of 6 acres are sprayed per day and that 150 gallons of liquid 

 are applied per acre. This average may not be maintained if the 

 water supply is inconveniently situated and the spraying machinery 

 is not kept in condition, but delays due to these sources are not nor- 



i See Quaintanee and St >ar (12), Johnson and Ilammar (13), Johnson (17), and Ilartzell (18). 



