NEW YOkK STATE MUSEUM 25 



At least some partly grown to full-grown larvae continue more 

 or less active into November with its freezing temperatures and 

 snow squalls, though it should be noted that in many New York 

 fields, especially of the early corn, there is in September a marked 

 cessation of activities and comparatively few hanging borings. 

 Many holes in corn stalks are closed about this time and this condi- 

 tion increases the difficulty of detecting the borer rather late in the 

 season. 



In order to secure data in relation to the possible benefits of 

 plowing under stubble, infested stalks were plowed under just 

 before the ground froze in the fall of 1920. Two areas were 

 selected, one a light, sandy soil and the other a moderately heavy, 

 moist to wet loam. The infested stalks were carefully selected, 

 labeled, laid in the furrows and then covered by plowing to a depth 

 of about 6 or 7 inches. An examination early the following spring 

 and on several subsequent dates resulted in finding no living corn 

 borers in the stalks plowed under in the wet, moderately heavy 

 loam. The earlier examinations of the material in the lighter soil 

 showed little or no mortality just after the ground thawed and a 

 gradual increase in the numbers of dead larvae until about the first 

 of May when none or very few survived. The experiments were 

 necessarily on a small scale and yet they indicate a heavy to com- 

 plete mortality in buried material in the moderately heavy, wet soil 

 and a presumably high ratio of deaths in lighter soils before condi- 

 tions had advanced sufficiently so that moths could escape. In a 

 general way, the conclusions based upon our inability to find a 

 notably greater infestation during the summer of 1919 in fields near 

 corn stubble, which had been plowed under the previous fall, to 

 the effect that borers did not winter successfully in any great 

 numbers in such material, were amply justified. 



Observations in 192 1 confirm the experience of the two preced- 

 ing seasons to the effect that early corn, other things being equal, 

 was most seriously affected. For example an examination Septem- 

 ber 14th of corn close to the Thomas Indian School showed that 

 golden bantam had a stalk infestation of from 15 to 20 per 

 cent, while nearby later planted corn of the same variety w^as 

 almost free from the insect. A large field of yellow dent corn 

 about three-fourths of a mile north of the Indian school showed 

 a 40 per cent stalk infestation, while just across the road from it a 

 very similar field of somewhat later corn had a stalk infestation of 

 only about 2 per cent. Similar variations were also noted in the 



