24 RKPOIRT OF THE STATE ExXTOMOLOGlST I.92I 



consequently they passed over the evergreen in great measure and 

 oviposited mostly in the white dent. It is worthy of note in this 

 connection that depressions in rolling fields, if conditions permit 

 early and vigorous growth, are likely to show a heavier infestation. 



The nearness of infested materials has a decided influence upon 

 infestation. The more serious damage occurred almost invariably 

 in fields near known sources of infestation and in a number of 

 cases the infestation began and was decidedly more marked on the 

 side of the field next an earlier infested area or near materials from 

 which moths might have emerged. 



The direction of the prevailing winds likewise has an important 

 influence. One of the most striking cases was that of two fields in 

 the Mohawk river bottom, one with a stalk infestation of 19.94 

 per cent and the other with only 5.46 per cent. The first was in the 

 direct line of prevailing winds from an infested area of the preced- 

 ing season and the other only alx)ut 200 feet north and outside the 

 presumable usual drift of the insects with the wind. 



There is nothing to show that certain varieties of corn are par- 

 ticularly immune from attack, though available data indicate that 

 the early and smaller varieties, particularly sweet corn and various 

 flint corns, are more likely to be badly infested. This is presum- 

 ably because these varieties are usually early and therefore in a 

 more attractive condition at the time the moths are depositing eggs 

 and secondly the smaller varieties of corn are unable to carry an 

 infestation that the larger com could support without serious injury. 

 This is most apparent in the early fall, because small varieties with 

 their early maturity show the eft'ects of injury at a time when dam- 

 age is comparatively inconspicuous in the later corn, and unless 

 care is exercised an unfair comparison may result. 



There is a connection between the stalk and stubble infestation, 

 since one field with a stalk infestation of 35 per cent showed a 

 stubble infestation of nearly 14 per cent. This stubble was 15 

 inches high and the proportion is therefore relatively greater than 

 it should have been under normal conditions. In another field, a 

 stalk infestation of about 10 per cent gave a stubble infestation of 

 less than i per cent. The above should be compared with the badly 

 infested Canadian area having a stubble infestation of nearly 60 

 per cent. These figures have a bearing on the expense which can 

 be incurred in the destruction of infested stubble or in taking extra 

 pains to cut it close to the ground. 



