CONTROL OF GRAPE-BERRY MOTH. 21 



quality of the laundry soap appears equally as great as that of the 

 resin. However, when the first and second sprays are applied and 

 the third omitted, leaving a longer period between the last spray 

 application and harvest time, it appears from field observations that 

 the resin soap adheres longer than the laundry soap. 



The resin fish-oil soap used was the commercial product obtained 

 in bulk and of the consistency of thick molasses. This soap is readily 

 dissolved in hot water and wets the clusters (PL IV, fig. 2) easily, 

 as is indicated by the use of but 75 gallons as compared with 100 

 gallons of laundry soap solution and 110 of soft soap solution. The 

 resin soap adhered the longest of any material tried. It was found 

 that 1 pound of this soap to 50 gallons was about as efficient as 2 

 pounds of the other soaps and at' the rate of 1 pound to 50 gallons 

 is as cheap. Xo difference in compatibility with Bordeaux and ar- 

 senate of lead could be noted among the different soaps. 



In conclusion it can be said that the resin fish-oil soap proved to 

 have all the desired qualities of a spreader and adhesive and in the 

 present state of knowledge appears the best spreader to use in grape 

 spraying. 1 



Combination Speats. 



In the Sandusky and Lake Erie island sections where the Catawba 

 variety predominates it is desirable to combine a fungicide for con- 

 trol of downy mildew, PJusmophora viticola. with the arsenical and 

 soap for rootworm beetle and grape-berry moth control. In the other 

 sections it is sometimes desirable to use the same combination for 

 blackrot and insect control. 



Bordeaux, either 2-2-50, 2-3-50, or 3-3-50, was used in combination 

 with arsenate of lead powder \\ and 2^ pounds to 50 with soaps at 

 the rate of 1 and 2 pounds to 50. In some of the experiments the 

 copper sulphate was omitted and stone lime, 2 pounds to 50 gallons, 

 was used. The combining of the insecticide with the fungicide 

 appeared to make no difference in insect control. 



In some cases slight burning of Concord and Catawba foliage and 

 serious burning of Ives foliage resulted from application of the Bor- 

 deaux-arsenate of lead-soap combination. The burning was most 

 noticeable during the abnormally wet season of 1917. Experiments 

 were conducted in 1918 to determine the material or combination 

 causing the burning. The combinations of arsenate of lead and soap 

 with Bordeaux proved responsible. Wherever the copper sulphate 

 was omitted and the arsenate-soap-lime mixture was used, no injury 

 resulted. 



'An appreciable difference was noticed in the length of time required to " wet " the 

 clusters of different varieties. Beginning with Niagaras, which were most readily wet, the 

 other varieties followed in about this order : Catawbas, Delawares, Ives, and Concords. 

 This difference is apparently closely correlated with the waxy bloom on the grape berries. 



