-605- 
dividual counties, choreas in each of the other 13 the -population of the insect 
showed no significant change in these 2 years. The heaviest -concentration of tho 
borer in Indiana in 1939 war ' found in a group of 5 counties near the eastern 
border of the State, namely, Adams, Wells, Allen, Jay, and Blackford, in which 
the numbers of borers per 100 plants were, respectively, 177 * 0 , 151 . 2 , l47#9» 
127,7, and 106.4. Less than 91 borers per 100 plants were present in each of 
the remaining 30 counties surveyed in Indiana, 
Ohio .— In Ohio comparisons of borer infestation in 1938 and 1939 are avail, 
able for 12 counties in the extreme northwestern part of the State. In this 
section, as a whole, the average of 108.7 "borers per 100 plants in 1939 was not 
significantly different from that of 133 in 1938. ' In none of the 12 counties war 
there a significant increase in number of borers from 1938 to 1939 r in 8 of them 
the populations of the insect for these 2 years remained at about the same level 
and in 4 a definite decrease occurred from 1938 to 1939* Van Wert County, with 
37^»8 borers per 100 plants, had the highest inf es tat ion’ of any county surveyed 
in Ohio in 1939* ' The next.. 3 highest counties in the State were Marion, Putnam, 
and Auglaize, • with populations of 278 . 6 , 211.6, and 201,4 borers per 100 plants, 
respectively. Only 10 other counties in northwestern and 1 in northeastern Ohio 
averaged over 100 borers per 100 plants in 1939 » populations below this level 
occurring in each of the other 44 counties surveyed in the State, Abundance of 
the corn borer was relatively low (averaging less than 67 borers > per 100 plants) 
in 30 counties surveyed in the eastern half of the State- where high infestation 
has never been recorded since the introduction and spread of the insect over the 
area# 
Michigan . --.Among 6 . counties of southeastern Michigan whose -data are com- 
parable for 1938 and 1939 $ there were 2 counties 'in which- populations of the 
corn borer increased significantly in 1939 over 1938 , 3 in which there was no 
change, and 1 in which the abundance of the insect decreased from 1938 to 1939 * 
The net result in this section was a. significant increase from 122.7 "borers per 
100 plants in 1938 to 162.0 in 1939* Huron County, at the extreme tip of the 
"thumb” section of Michigan, with its average of 595 "borers per 100 plants, ex- 
ceeded all other counties in the State in 1939 and was the heaviest infested 
county outside of New England. Pour other counties in eastern Michigan— Genesee, 
Tuscola, Lapeer, and I rgham— had high populations of 447.0, 4l6.4, 376.2, and 
347.0 borers per 100 plants, respectively, .and 11 other counties in -the State 
averaged between 101 and 300 borers per 100 plants. Each of -the remaining 15 
counties surveyed in Michigan averaged less than 100 borers per 1Q0 .plants# 
Pennsylvania . — Corn borer infestation was relatively light in 5 counties is 
northwestern and l4 in northeastern Pennsylvania. surveyed' in 1939. Pucks County, 
on the eastern border of the State, with l42 borers "per 100 plants., was the only 
county in Pennsylvania in which the average number of borers per 100 plants was 
greater than 23 . , 
Hew York#— With the exception of 6 courties 'in Hew York State proper and 2 
on Long Island, populations of the corn borer in the 48 counties surveyed in thai 
State in 1939 were relatively flight (less than 95 'borers per 100 "plants). Hiagai 
County, with 227 borers per 100 plants, was the only high county in the western 
part of Hew York. In eastern Hew York, Albany County had 491.4 borers per 100 
plants, and the counties of Nassau, Suffolk, Otsego, Benesselaer, Columbia, and 
Pulton were infested with 251.8, 191.2, 177 . 0 , 160.4, 139 . 8 , and 101.8 borers per 
