80 THE GRAPE ROOT- WORM. 



In examining the yields for the various plats it will be observed 

 that in the first year of the experiment plats I, II, III, and IV fell con- 

 siderably below the unsprayed and unfertilized plat. This condition 

 is due in a great measure to the fact that vines in plats V, VI, and VII 

 were in a somewhat more thrifty condition at the outset of the experi- 

 ment. The soil in these plats grades to a clay loam and has been 

 enriched somewhat by the wash from an elevation immediately south 

 of them. While the untreated plat shows great improvement in 

 yield simply as a result of thorough cultivation, yet the annual 

 increase in yield on this plat was much less than that upon the 

 treated plats in the same soil. 



In addition to this increase in crop yield there was noted a great 

 improvement in the quality of the fruit both in size of berries and of 

 clusters. Plate IX, figure 2, gives a comparison of the size and com- 

 pactness of fruit on a vine in the sprayed portion as compared with 

 fruit on a vine in the unsprayed portion shown in Plate IX, figure 1. 



It was also found that the fruit in the sprayed plats remained firm 

 and that there was practically no loss from shelling of the berries, 

 whereas the fruit and stems in the unsprayed plat were badly mildewed 

 and there was a great deal of shelling of berries. This benefit is 

 derived from the fungicidal effect of the Bordeaux mixture. This 

 increase in crop yield has also been accompanied by a marked improve- 

 ment in the vigor of the vines throughout this vineyard. Practically 

 all of the vines are now in a condition to produce a full crop of fruit, 

 and there is no reason why this vineyard should not continue to 

 produce as profitable crops as it did previous to its infestation, pro- 

 vided it is subjected to treatment similar to that which it has received 

 during this investigation. 



Plate VIII affords a comparison of the growth of vine at the 

 beginning and at the end of the experiment, the upper figure show- 

 ing the vineyard at the beginning of the experiment, and the lower 

 figure after three years' treatment. 



RENOVATION EXPERIMENT ON A YOUNG VINEYARD. 



About the year 1900 there was a heavy planting of new vineyards 

 throughout the Lake Erie grape belt. Scarcely had these young 

 vines come into bearing when the owners noticed a rapid decline 

 both in their crop yield and in vigor of vines. Close observation 

 indicated that this decline was due largely to injury by the grape 

 root-worm, and that the decline of these young vines was even more 

 rapid than in the case of older, well-established vines. In many 

 vineyards it was found that young vines had been killed outright in 

 a single season. 



