60 
BULLETIN 1476, U. S. DEPARTMENT OF AGRICULTURE 
Table 17. — Extent of injury and infestation by the European corn borer in 
celery, New England area, 1922 
Field 
Locality (Mass.) 
Date 
examined 
(1922) 
Plants showing 
injury 
Plants contain- 
ing larvae 
Larvae per in- 
fested plant 
No. 
Num- 
ber i 
Per 
cent 
Num- 
ber i 
Per 
cent 
Aver- 
age 
Maxi- 
mum 
1 
Sept 25 
Sept. 26 
Sept. 20 
Oct. 5 
Oct. 5 
Sept. 26 
Sept. 26 
Sept. 26 
Oct. 5 
Sept. 30 
Sept. 30 
Sept. 28 
8 
32 
26 
151 
140 
14 
9 
78 
38 
3 
8 
120 
L. 
6.4 
5.2 
30.2 
28.0 
2.8 
1.8 
15.6 
7.6 
.6 
1.6 
24.0 
2 
13 
9 
42 
45 
3 
5 
32 
16 

2 
69 
0.4 
2.6 
1.8 
8.4 
9.0 
.6 
1.0 
6.4 
3.2 
.0 
.4 
13.8 
1.00 
1.00 
1.30 
3.52 
2.93 
1.00 
1.00 
1.37 
1.50 
.00 
1.00 
1.32 
1 
2 
Do ... 
1 
3 
Do 
3 
4 
Do 
8 
5 
Do . 
10 
6 
Belmont. - . -■ 
1 
7 
Do 
1 
8 
Medford 
3 
9 
4 
10 
11 
Watertown 
Do 

1 
12 
Woburn 
3 
Total 
627 
~~~I6.T 
238 
Average 
3.96 
2.00 
1 
500 plants examined in each field. 
Table 17 shows that in 
the 12 fields under observa- 
tion an average of 10.4 per 
cent of the celery plants 
showed injury and that an 
average of 3.96 per cent of 
the plants contained the 
borer at the time of the ex- 
amination, with an average 
of two larvae per infested 
plant. 
Beans 
Injury to beans (fig. 28) 
was confined principally to 
the stalks with an occa- 
sional infestation in the 
pods. Infested pods were 
usually unfit for sale, but 
less than 1 per cent of the 
total pods were affected in 
any of the commercial 
fields examined. In in- 
stances of severe injury to 
the stalks, the affected por- 
tions broke over and re- 
sulted in a decreased yield 
of pods. In some of the 
small home gardens as high as 100 per cent of the plants and 22 per 
cent of the pods were infested. Field counts made in 10 bean fields 
of the Boston area, showing average infestation, are given in Table 18. 
In the bean fields under observation (Table 18) an average of 
3.55 per cent of the plants showed injury and 3.22 per cent con- 
tained larvae, with an average of 1.18 larvae per infested plant. 
Fig. 28. — Green beans, showing the work of Euro- 
pean corn-borer larvae 
