22 



REPORT OF THE STATE ENTOMOLOGIST I92I 



were strikingly shown in the field belonging to Annie Collins on 

 the Scotia flats. This field had a stalk infestation of nearly 35 per 

 cent and on August 25th there was a noticeable amount of injury 

 due to the breaking over of the corn and on September 3d a 

 careful examination showed that 10.45 per cent of the stalks were 

 broken over. This condition makes harvesting difficult, not to 

 mention the danger of fodder and grain mildewing in damp weather. 

 There was similar breaking in a number of other fields, though not 

 to such a great extent. 



The third type of injury is due to the borers entering the ear 

 itself. This may occur at the tip, the borer entering through the 

 husks on the side or by tunneling from the stalk through the stem 

 of the ear into the cob. This latter method of entry is rarely 

 noticeable until considerable damage has been inflicted. Records 

 obtained from several fields showed 5 per cent to 7 per cent of the 

 ears more or less injured by borers. 



Repeated examinations in the infested area indicated as a rule 

 comparatively slight damage where the stalk infestation was 10 

 per cent or less and by no means serious injury when the stalk 

 infestation ran to about 30 per cent and ear injury as high as 7 

 per cent. It is obvious, furthermore, that there can be a larger 

 percentage of ear infestation in field corn with less relative damage 

 than in the case of sweet corn. 



The approximate relation between stalk infestation and ear 

 infestation in a sparsely infested area is indicated by the following 

 tabulation : 



Stalk and ear infestation, Schenectady area 1920 



Stalk 

 infestation, 



Name per cent 



Annie Collins 34 . 85 



Flats 



Fred Fagel 14 . 53 



Mohawk ave. 



Schairer 10.38 



Charlton rd. 



Brewster 4.4 



Vley rd 4.72 



Theuner no. 5 8.8 



Freeman's bridge 



Theuner no. 3 ? 



Theuner no. 4 ? 



Ear 



infestation, 

 per cent 



7-3 



11.7] 

 ' ' > 7 . 6 Average of figures 



5-9 



(10?) 1 



1.08 



2.6 

 1.2 



Mr Brewster first estimated 

 5 per cent and then raised 

 it to 10 per cent 



