56 
BULLETIX 1476, U. S. DEPARTMENT OF AGRICULTURE 
Table 15. — Per cent of tassels broken over as a result of European com oarer 
injury 
Type of corn 
Sweet.. 
Flint.. . 
Dent i. 
Fodder. 
Pop.... 
Total.... 
Average- 
Number Tassels 
of fields counted 
11,913 
5,428 
6,700 
7, 238 
500 
Tassels 
broken 
over 
3,584 
1,412 
992 
1,204 
227 
419 
Per cent tassels broken over 
Average 
30.1 
26.0 
14.8 
16.6 
45.4 
23.3 
Maxi- 
mum 
35.4 
16.5 
22.1 
Mini- 
mum 
1.3 
2.7 
8.2 
1 Limited to experimental plat counts. No dent corn grown for grain within the Boston area. 
Table 15 shows that the average of broken-over tassels as a result 
of larval injury ranged from 14.8 to 45.4 per cent in the different 
types of corn examined, with an average of 23.3 per cent of the 
tassels in the entire lot. In fields representing maximum infesta- 
tion the percentage of broken-over tassels was much higher than 
these figures indicate. 
EXTENT OF INJURY TO VEGETABLES, FLOWERS, AND FIELD CROPS 
NEW ENGLAND 
The extent of injury and loss to vegetables, flowers, and field 
crops in Xew England, caused by the corn borer, has not been severe 
in most instances, seldom exceeding 5 per cent of the total value of 
any crop. There has been, however, a very considerable increase 
each year in the infestation of these crops. In 1917, when the field 
investigations on the corn borer were started, it was difficult to find 
infestations in crops other than corn, although according to Vinal 
(70) certain of the flowers, notably dahlias, were occasionally at- 
tacked. Infestation has progressed to a point where in 1921 and 
1922 most commercial fields of the more susceptible vegetable and 
flower crops, such as rhubarb, beets, celery, beans, peppers, dahlias, 
asters, and gladioli, were infested in localities in Massachusetts where 
the corn borer has become at all numerous. The infestation in 
some of the beet and celery fields during 1922 was especially pro- 
nounced and led the growers of these crops to view with apprehen- 
sion the increased damage to these vegetables. 
Formerly most of the infestations in vegetables and flowers were 
confined to weedy fields, and along field borders where the plants 
were growing among or in close proximity to infested weeds or 
corn, but during 1922 these crops were commonly subjected to ap- 
preciable infestation and injury even in fields that were kept free 
of weeds and isolated from areas of susceptible weeds or corn. The 
following discussion applies principally to conditions existing dur- 
ing 1921 and 1922 with respect to the more important and susceptible 
economic hosts of the corn borer. During 1923 and again in 1924 
a marked reduction occurred in the extent of infestation and injury 
to vegetables, flowers, and field crops, a reflection of the general 
decrease in intensity which developed in the Xew England area 
during those two years. 
