154 STATE BOARD OP AGRICULTURE. 



Owing to the fact that in each case the spraying was omitted at a 

 critical time and probably also because they Avere not sufficiently im- 

 j)ressed with the importance of thorough w^ork, the results in both vine- 

 yards were less satisfactory than had been hoped for. While the loss of 

 grapes was quite serious, the experiment served to impress upon the 

 owners as well as their neighbors, who were carefully watching the re- 

 sults, the fact that in order to be effectual against this disease, it was 

 highly essential to keep the vines covered with a fungicide from the time 

 the growth appeared until the crop was gathered. 



In 1907 and 1908, similar experiments were also carried on by Fred 

 J. Diehl, of Paw Paw, and by Frank and Charles Stainton, of Lawton, 

 all of whom had sprayed in 1906 and hence were able to do good work. 

 The results obtained by them, as well as by Messrs. Thornton and Morrill 

 in those years, were quite satisfactory as although in 1007 in particular, 

 the conditions were so favorable to the disease that upon unsprayed vine- 

 yards the crop in many instances was entirely destroyed, the actual loss 

 from black-rot in any of the vineyards in which the cooperative experi- 

 ments were carried on was hardly worth considering. 



The weather in June, 1908, was also conducive to the development of 

 black-rot and it threatened to do serious harm upon vines that had not 

 been sprayed, but a severe drouth prevailed in July and August so that 

 in most vineyards the loss was comparatively slight, ranging from fif- 

 teen to fifty per cent of the crop, except in a few instances where the 

 vines were neglected in which cases the crop was not worth gathering, 

 from seventy to ninety per cent of the grapes being attacked by black-rot. 



As all the experimenters had become more expert in their spraying 

 operations and impressed with the need of regular and thorough work, 

 they were able to almost entirely control the disease so that the loss was 

 little, if any, more than one-tenth of one I3er cent, or certainly not more 

 than twenty-five cents per acre as compared with a direct loss of from 

 fifteen to twenty-five dollars per acre where the vines were unsprayed. 

 In estimating the loss resulting from black-rot, the extra expense in 

 packing grapes owing to the necessity for trimming the diseased clusters, 

 should not be overlooked as this in many cases will fully equal the 

 entire expense of spraying the vineyard for the season, to say nothing of 

 the deterioration in the value of the fruit, owing to the mutilated clusters 

 and the injury to its appearance from the extra handling. 



The cost of spraying varies of course with the strength of the Bordeaux 

 mixtures used, as well as with the number of applications, the size of 

 the vines, and the thoroughness with which the work is done. Particu- 

 larly in the case of when the rot is very troublesome, experiments show- 

 that it is penny wise and pound foolish to attempt to economize either 

 in the amount of material used, or in the time taken for making the 

 applications, until one has made sure that the vines are thoroughly 

 sprayed. 



For the spraying of vineyards it was found advisable to use Bordeaux 

 mixture containing for the earlier applications four pounds of copper 

 sulphate and four pounds of stone lime in fifty gallons of water, but 

 after the first of July the amount of each can be reduced to three pounds 

 and, if it becomes necessary to spray after July 15, two pounds of copper 

 sulphate and one pound of lime will be sufficient for fifty gallons. By 

 reducing the amount of lime for the later applications, there will be no 



