36 Farmers’ Bulletin 1294. 
METHODS OF CONTROL EFFECTIVE UNDER RESTRICTED CONDI- 
TIONS. 
REGULATING TIME OF PLANTING. 
Injury to the early maturing crops of sweet corn may be reduced 
to an uncertain extent by regulating the time of planting. On many 
of the farms and market gardens, where a series of sweet-corn plant- 
ings are made on different dates, there is usually a very noticeable 
difference in the amount of injury to each planting, even where these 
consist of the same variety, in adjoining areas and under the same 
soil] conditions. 
The first planting of early sweet corn is usually injured by the 
borer to a much greater degree than plantings made from 10 days 
to 3 weeks later. In Massachusetts sweet corn planted from about 
April 15 to May 10 has been injured to a greater extent than sweet 
corn planted from about May 20 to May 30. In New York the 
earliest planted sweet corn (about May 10) is usually infested to a 
greater degree than that planted about 10 or 20 days later. The 
dates of these plantings necessarily will vary from year to year, 
according to weather conditions, and also with the local development 
of the season. This method can not be applied for limiting the 
amount of injury to field corn or late crops of sweet corn in New 
England, according to present information. These crops are at an 
attractive stage during the late summer, when the insect is most 
active and when many of the moths of the second generation in New 
England are depositing their eggs directly upon the ears. 
The variation in the amount of injury to early sweet corn planted 
at different times may be explained by the fact that at this time of 
year the moths apparently prefer to deposit their eggs on well- 
developed plants which have not reached the matured-tassel stage. 
Subsequently, when later-planted corn becomes available, most of 
the moths have deposited their eggs, and these later plantings escape 
serious injury. Although egg masses are frequently found on the 
leaf blades of very small corn plants, the young borers commonly 
leave such corn soon after hatching, and enter weeds or other plants 
near by which have reached a more advanced stage of development. 
TRAP CROPS. 
Attention has been called to the fact that the earliest plantings of 
sweet corn usually attract many of the moths which have developed 
from the overwintering borers, and that these early plantings are 
commonly very heavily infested. This immediately suggests the 
use of very early planted sweet corn in fields intended for a main 
crop of field corn or late sweet corn to act as a trap crop; such 
plantings to be carefully destroyed, with the contained borers, as 
soon as the ears are harvested, or preferably just before that period, 
where the grower is willing to sacrifice the ears and use the plants 
as green feed for live stock. 
This method of limiting damage to the main crop of field corn or 
late sweet corn might be particularly useful in the one-generation 
areas of New York. In the two-generation area of New England it 
can only be used to advantage on the larger fields or farms, judging 
from results secured at the present writing. On the small farms 
