GRAPE-BERRY MOTH IN NORTHERN OHIO. 
11 
PLACE OF OVIPOSITION ON THE VINE. 
It was found that a vine of the Clinton variety set in a row of 
Concords was heavily oviposited upon before the Concord berries 
were formed. For use in the spacing of spray nozzles for the set- 
nozzle method of spraying, the place of oviposition on the vine 
seemed important. The place of oviposition on this one vine by 
the spring brood of moths was recorded and the data are presented 
in Table XIV. The vine was trained according to the fan system 
of grape training which is generally used for all varieties in the north- 
ern Ohio sections. In the fan system the vine growth which is 
trained to an upright trellis is annually renewed to within a short 
distance of the ground. The vines are cut back usually to from 2 to 
4 canes and as many spurs each year; the canes are spread out and 
tied to the trellis obliquely, giving the shape of a fan. 
Table XIV. — Place of oviposition on vine by spring moths of the grape-berry moth 
under natural conditions in vineyard, Venice, Ohio, 1917. 
Dis- 
tances. 
Num- 
ber of 
clusters. 
Num- 
ber 
grapes 
bearing 
eggs. 
Num- 
ber 
eggs. 
Num- 
ber 
eggs 
per 
cluster. 
Percentage of— 
Place on vine. 
Depo- 
sition 
in this 
space. 
Clusters 
in this 
space. 
Inches. 
21 
21-33 
33^9 
15 
23 
7 
82 
260 
124 
107 
333 
190 
7 
15 
29 
17 
53 
30 
33.3 
Between first and second wire 
51.1 
15. 5 
Total 
45 
466 
630 
""'l4."6' 
100 
100.0 
The figures in Table XIV agree with the usual observation that 
the clusters near the ground are less heavily infested than those 
higher up on the vines. Thirty per cent of the deposition occurred 
between the middle wire and top wire, whereas but 15 per cent of 
the clusters were in that space. These figures likewise agree with 
field observations in that the heavy infestation is generally where 
the clusters are well covered with foliage, a condition which prevails 
near the top of the trellis. 
In Table XV are presented records of the length of the incubation 
period of eggs of the first brood. The average number of days 
required for incubation was 4.39, the maximum 8 days, and the 
minimum 3 days. These figures include both insectary material and 
eggs collected in the vineyard when the date of deposition was known. 
In obtaining the eggs from the vineyards all eggs were removed from 
the vines each day. 
