26 REPORT OF THE STATE ENTOMOLOGIST I92I 



immediate vicinity of Silver Creek, the insect l^eing notably more 

 abundant in early fields. 



Insect activities commenced considerably earlier than in 1920. 

 The first pupa was found at Scotia May 30, 192 1, the first moths 

 at both Scotia and Silver Creek, June ii6th, the first egg mass at 

 Scotia June i6th and at Silver Creek June 22d, according to data 

 supplied by Federal observers. Developments at Port Stanley, 

 Ontario, closely paralleled those in New York, the first pupa being 

 found May 30th, the first empty pupal case June i6th and the first 

 egg mass June 25th, according to Mr H. G. Crawford who sup- 

 plied the data. Fully 20 per cent of the larvae at Scotia were nearly 

 full grown June 28th, the remainder being half grown or smaller 

 and limited mostly to the upper portion of the stalk. A pupa 

 was found by Mr Harmon July 25th and the probabilities then indi- 

 cated the development of a fair sized second brood, which latter 

 was apparently checked by a period of unusually cold weather, 

 though there was a very small, practically negligible second brood. 

 The same conditions prevailed in the western part of the State and 

 in Canada. With the experience of the past three seasons as a 

 guide, it would presumably require a very unusual combination of 

 favorable climatic conditions to produce in our New York areas a 

 second generation capable of causing appreciable injury. 



Observations upon the good habits of the borer were continued 

 and as in previous years very few were found in other plants in the 

 near vicinity of corn. These conditions resulted in the modification 

 of both federal and state quarantine regulations and their limitation 

 to corn, broom corn, all sorghums and sudan grass. This greatly 

 simplifies the enforcement of these regulations and gives practically 

 the same protection as the more sweeping provisions of the earlier 

 quarantine. 



Economic importance. The history of the European corn borer 

 in America plainly shows that this insect may cause serious to 

 extremely severe injury under certain conditions. The damage 

 in eastern Massachusetts, owing to the development normally of two 

 generations each season, appears to be more general than in areas 

 where but one brood is produced, though even in that section by no 

 means all the corn is greatly damaged. This may be due to a variety 

 of causes which can not be discussed in this connection. 



A somewhat serious injury to early corn in Ontario, Canada, in 

 1920 and decidedly more general and severe damage in 1921 con- 

 clusively establishes the probability' of extended losses in that area 



