February, ’24] huber & neiswander: corn borer investigations 
127 
two counties is 15 percent in favor of Ashtabula. In our opinion these 
data will not permit us to make any superlative claim for our efforts last 
spring. Similar studies of infestation were carried on in Lorain, 
Cuyahoga and Lucas counties. The maximum infestation in these 
counties was one, three and seventeen percent, respectively. 
In the course of these investigations information was secured in regard 
to natural enemies. In only one instance has bird attack been at all 
noticeable. This was in a field of yellow dent which had 7>^ percent 
infestation and which was located near a wooded area. Actual count 
showed about 20 percent of the borer entrances attacked. Due to the 
great number of crows present and to damaged ears in this field the crows 
were suspected of the attack. 
Insect parasites were few indeed. In 410 stalks of sweet and field corn 
collected in northeastern Ohio and cut open between September 26 and 
November 15, 510 borers and 9 pupal cases of Exorista nigripalpis 
Towns were taken. This gives a 1.7 percent parasitism. These same 
stalks yielded an average of 1.26 borers each. 
Three weed hosts were recorded, viz: smartgrass, pigweed and rag¬ 
weed. Weeds artificially infested were severely attacked. 
In an attempt to explain the evident increase of borer population in 
pite of clean up measures a careful study of stubble conditions was made. 
°n a one-half acre patch of Golden Bantam planted May 1 a ten percent 
Infestation was noted. After the corn had been harvested and the 
fodder fully mature ninety-three of the infested stalks were carefully 
examined with the startling result that 47 percent of them had borers 
A not higher than six inches from the ground level, while a few were even 
below the surface level. If this fodder had been cut at the usual 
height for this community, nearly 300 adult larvae would have been 
left in the stubble in this small patch. Examination of less mature 
fodder revealed fewer borers in the stubble. Further data were secured in 
regard to infestation present in stubble of different heights in field com. 
Two hundred infested stalks from corn in Lake and Lucas counties were 
carefully stripped of their leaves and the distance of the entrance holes 
from the ground was noted in each instance. Holes more than twenty - 
four inches from the ground were not considered. In this connection it 
is well to mention that twenty-four inches is about the maximum 
height of corn stubble in Ohio. Tabulation of data follows: 
