REMEDIAL MEASURES. 
71 
So serious was the injury of the larvae to the roots at this date that 
the large crop of fruit which some of these vines were carrying was 
actually shriveling up and dropping to the ground. By the fol- 
lowing spring many of these vines had either died outright or were 
in a very weakened condition. Plate IV, figure 2, gives an example 
>f the manner in which the fibers had been removed from the roots 
of many of these young vines by the larvae of the root-worm, and 
shows the limited growth of new canes as a result of the infestation 
which rendered the vine incapable of producing a crop of fruit during 
the coming season. Thus the variety of conditions existing in this 
vineyard was such as to enable us to work out several features of 
the problem on the same block, namely, the effect of a poison-spray 
application on vines of different varieties, of different ages, and in 
different stages of injury, all growing side by side under practically 
the same conditions. All of the vineyard was subjected to the 
same treatment in regard to cultivating, fertilizing, and spraying, 
with the exception of six rows running through the center of the 
block (PI. VI) which cut through all four of the sections mentioned 
above. These six rows were reserved as a check and from these 
the spraying alone was withheld. 
Below are given all of the data relating to the experiment conducted 
on this vineyard during the seasons of 1907, 1908, and 1909, together 
with the results obtained. 
As the time for the emergence of the beetles from the soil drew 
near daily visits were made to this vineyard during the latter end 
of June and early July, 1907. On July 15 an occasional beetle was 
found feeding on foliage near the ground. All preparations had 
been made for spraying as soon as the first beetles appeared, and 
the first application was made at this date. The sprayer used was 
a gasoline-engine power outfit constructed especially for vineyard 
work (PL X, fig. 2). The regular Bordeaux formula, 5-5-50, was 
used, and to this 3 pounds of arsenate of lead were added, this latter 
ingredient being the active poison agent of the spray. A pressure 
of about 100 pounds was maintained throughout the application, 
and about 100 gallons of spray mixture were applied per acre. Fixed 
nozzles were used of the eddy chamber type. 
On July 23 a second application was made, the same formula 
being used and the same pressure maintained. 
During the season of 1908-9 the same spray formula, machinery, 
and nozzle arrangement were used ami the same pressure main- 
tained. The only varying factor was the dates of application, which 
varied each season with the date of emergence of the beetles. To 
facilitate comparison, the dates of application, effect of spray on 
egg deposition, prevalence of larvae at roots, and crop yield as com- 
pared with the unspraved check are tabulated for the three seasons. 
(Tables XXVI. XXVII. and XXVIII.) 
