Seasonal-History Studies on the European Corn Borer in Michigan

1931 ◽  
Vol 24 (2) ◽  
pp. 372-379 ◽  
Author(s):  
G. T. Bottger ◽  
V. F. Kent
1959 ◽  
Vol 91 (12) ◽  
pp. 798-806 ◽  
Author(s):  
J. A. Mutchmor

In southwestern Ontario the European corn borer, Ostrinia nubilalis (Hbn.), produces two flights annually. The first flight, beginning in June, consists of moths from larvae that have overwintered. The midsummer, or second, flight begins late in July or early in August, and its moths are the progeny of the first flight. Until about 20 years ago the borer produced only one annual flight and was thought to be univoltine. The change in the seasonal history of the borer in Ontario was described by Wressell (1953) and Miller (1956). The literature describing similar changes in parts of the United States has been reviewed by Lees (1955) and Everett et al. (1958). Wressell (1953) summarized light trap collection data of moth flights in the Chatham, Ontario, area for the years 1932 to 1951. The summary includes the percentage of the moths that were from the midsummer flight, and it is evident that the size of this flight varies greatly from year to year. Aside from its intrinsic interest, it would be of some economic value to know what governs the size of the midsummer flight. This is a report of studies undertaken to examine the case, and to relate the findings to the larger problem of why the borer now produces a second flight where formerly it produced only one.


1947 ◽  
Vol 79 (5) ◽  
pp. 81-83 ◽  
Author(s):  
Geo. Wishart

The seasonal history of an insect has an important relationship to the success or failure of any efforts to usr parasites in its control. In the work on parasites of thr European corn borer, Pyrausta nubilalis Hubn., over a period of years, the writer has had an opportunity to observe the changes which have taken place in the seasonal history of this insect in Western Ontario. It was shown by the writer (Wislwt, 1942, 1944) that there was a gradual and rather consistent increase in the proportion of the population which had two generations instead of one. The present paper presents further data pertinent to this subject.


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