The European Corn Borer. ot 
and market gardens, which now predominate in the badly infested 
portion of New England, any benefits to field corn or late sweet corn 
which may be derived from the destruction of a trap crop appear 
to be partly nullified by the flight of the second-brood moths from 
adjoining areas of weeds or early corn which has not been destroyed. 
Caution.—7'vap-crop plantings which are not destroyed at the 
proper time constitute a menace to later corn or other susceptible 
et a SELECTION OF VARIETIES. 
Field observations and experimental tests have indicated in some 
instances that certain varieties of field corn and of sweet corn are 
less susceptible to severe injury by the corn borer than others. 
This apparent difference is usually involved to a certain extent 
with the time of planting and also with the rapidity or size of growth 
and the consequent period of maturity. It does not appear, therefore, 
that any variety on which observations have been made to date 
possesses anything like entire immunity from attack by the borer, 
although some varieties suffer much Jess injury than others. 
The varieties of corn having large, heavy stalks seem able to 
withstand injury to a much greater extent than the slender varieties. 
This seems especially true of the large, robust dent varieties, such as 
are grown widely in the Corn Belt States. Throughout the present 
areas of infestation the northern-grown, early maturing varieties of 
flint field corn predominate and are usually injured to a greater 
degree than the later maturing varieties of dent field corn. 
The stalks and grain of the early maturing varieties of dent 
field corn appear to be quite susceptible to infestation. Com- 
pared with the flint or early dent varieties, the relatively smaller 
amount of injury observed in the late varieties of dent corn, at 
least in New York and New England, may be due to their slower 
development and later maturity, and also to the fact that their 
greater bulk is able to withstand the work of the borers without so 
seriously affecting the development of the stall or ear. 
PLOWING UNDER. 
The effectiveness of plowing down infested corn stubble, weeds, 
and crop remnants as a farm practice in reducing corn-borer damage 
has been made the subject. of extensive investigation. It has been 
determined that by thoroughly plowing under this infested material 
during the fall, especially in the soils of eastern Massachusetts, 
a large proportion of the borers contained in such material are 
destroyed. This measure alone will probably prove ineffective. In 
order that it may be rendered even partly effective, practically all 
of the infested material in infested fields must be plowed down to a 
depth of at least 6 inches in soils of ordinary texture. Deeper plowing 
increases the effectiveness of this operation and should be adopted 
when practicable, whenever the character of the soil will permit. 
Breaking down the cornstalks, stubble, or other standing plant 
material with a heavy roller, or by dragging with a heavy pole or 
iron rod before plowing them under, greatly increases the eftective- 
ness of the work. Disk harrowing immediately after plowing serves 
to break up large clods of soil and aids in burying the plant material 
where the soil is in a condition that will allow this treatment. 
