-54s- 
Hew Jersey . — The European corn 'borer increased .appreciably in abundance in 
the State of Hew 'Jersey, from an average of 70. 1 borers per 100 plants in 1939 
to 109 in 19 Uo, .although many of the individual counties showed little signi- 
ficant change in the general level of their populations in the 2 years. The 
increase was somewhat more pronounced in the southern than in the northern half 
of Hew Jersey. Burlington and Monmouth Counties, near the center of the Stale, 
with 505.4 and 387*4 borers per 100 plants, respectively; had the highest popu- 
lations of the insect in Hew Jersey in 1940; in 1939 these 2 counties averaged 
220. S and 98.6 borers per 100 plants, respectively. Bergen County had 234 borer 
per 100 plants in 1940 and 4 other counties averaged 101 to 200 borers per 100 
plants. The remaining 12 counties in the Stale together averaged 37.1 borers 
per 100 plants in 1940. 
Delewa.ro, Maryland, and Virgini a. — Striking increases in numbers of the 
corn borer from 1939 were found in 1940 in Delaware and on the Eastern Shores 
of Maryland and Virginia. The average number of borers per 100 plants in Dela- 
ware in 1940 was 53*2, as compared with 8.9 in 1939; in the combined counties 
.of Somerset, Wicomico , and Worcester, in Maryland, the 1939~t°“1940 increase 
was from 5«S to 235*3 borers per 100 plants; and in Accoma.c and Horthanpton 
Counties, in Virginia, the change was from 4l 0 4 borers per 100 plants in 1939 
to 512.9 in 1940, Some of the highest populations of the European corn borer 
known in the United Stales were observed in 1940 in' Princess Anne County, on 
the mainland of Virginia, where the average number of borers per 100 plants, as 
determined by the survey, was 601.2. Individual corn plants in some fields in 
this county contained more than 100 corn borer larva.e. 
Summer Abundance in Sweet Corn 
In the summer of 1940, surveys were conducted in several counties of 
Connecticut, Maine, Hew Jersey, Hew York, and Ohio, to determine, the relative 
abundance of the European corn borer in early market sweet corn. A' The fields 
surveyed represented the most heavily infested ones within a given locality. In 
each field 100 plants were examined for percentage of plant infcste.tion and 10 
infested plants \\rcre dissected, idaenever possible, to learn the average number 
of borers per infested plant, the product of the 2 figures giving the average 
number of borers per 100 plants. The data on sweet corn are presented in table 
3* 
The corn borer was only half as abundant in early market sweet corn in 1940 
as in' 1939, according to an average of the data fro i all l4 counties surveyed. 
In Hew Haven County, Conn., the unusually high average of 1,980 borers per 100 
plants in 1939 declined to 493 in 1940, and in Lucas County, Ohio, there were 
497 borers per 100 plants in 1940, as compared with S17 in 1939. A trend toward 
increa.se appeared in Burlington County, H. J.., where the overage number of borer 
per 100 plants changed from 417 in 1939 to 510" in 1940. In most of the counties 
surveyed in' eastern Hew York, including' Hassau and Suffolk on Long Island, popu- 
lations of the borer in sweet corn were lower in 1940 than in 1939» with maxi- 
mums of 509 and 425 larvae per 100 plants occurring in Albany and Columbia 
Counties, . respectively. Fewer borers were also found in this crop in 1940 than 
in 1939 in comparable counties surveyed in Maine. 
• ^ The ' survey of sweet corn in Hew York was made in cooperation v/ith the 
Agricultural Experiment Station, Geneva, H. Y. , and the data, on infestation in 
this crop in Maine were kindly furnished by the State department of agriculture. 
