Rose chafer damage .... spraying

I got to the vineyard and found that a few of the 2nd year Lacrescent had major damage. But it most were minor damage. The new plantings got hit harder.

Since None of these vines are in bloom, and wind was very calm (and most of the other grapes were done or very close to being done blooming) I sprayed Sevin on the 48 second year LaCrescent and the 300 new plantings.

Here is my estimate of damage.
(my criteria)
4- Defoliated
3- Severe damage (some green left)
2- moderate damage (half the leaves show some damage)
1- Light damage ( ~ 1/4 leaves show damage)
0- No damage (no visible damage or so few, that it is barely noticable)

2nd year lacrescent (48 total)

#vines Damage
2 ----4
4 ----3
15----2
15 ------1
12 ------0

3rd year Concord (23 total)

Number of vines Damage
0 ----4
0 ----3
4 ----2
10----1
9 ----0


1st year Frontenac (100 ..25 only have shoots, 4 showed no life)
Number of vines Damage
6 ----4
10----3
20----2
40----1
24----0

1st year LaCrescent (99 total - 9 showed no life)
Number of vines Damage
8 ----4
10----3
10----2
25----1
37----0

1st year Prairie Star (100 .. 100% have leaves!)
Number of vines Damage
10 ----4
10----3
10----2
10----1
60----0