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JOURNAL OF ECONOMIC ENTOMOLOGY 
[Vol. 17 
in the open field. During the 1922-1923 season the average death rate 
for all larvae studied (5149) from 19 localities and representative of the 
entire infested area was 6.4%, the average mortality above ground 6.5% 
and that for the material below ground 6.2% which was even less than 
that on or above the surface. It should be mentioned, however, that 
in ploughed land in the Port Stanley region in the poorly drained parts 
of the field, where the refuse was wet for long periods at low temperatures 
above freezing, the mortality both above (12%) and below (13.8%) 
the surface was relatively high and well above the average for the field. 
In the reasonably well drained parts of the field the mortality in the 
material above the ground was 4.6% and in that below ground 7%. 
In no real sense have these mortalities importance in practical control. 
Decrease in the Number of Larvae in Material Buried Below 
Ground 
Of the burial experiments to determine the rate of reduction of the 
numbers of larvae in the infested stalks below ground, the most pertinent 
were those in which loose bundles of from 3-10 stalks were buried at a 
uniform depth of 6 inches. They were in series of from 5 to 20 burials 
each and were taken up at intervals. The numbers of dead and living 
larvae in the stalks and the surrounding soil were recorded and checked 
against an estimated expectancy of larvae based upon the average 
population of the stalks used in the experiment. Such burials were made 
in each fall month and were in a variety of soils and situations such as 
sand, sand-loam both well drained and wet, clay-loam and clay both well 
drained and wet. 
A review of the results throughout the study indicate (See Tabulation 
No. 1, Sect. 2, 3 and 4) that the full grown larvae gradually leave the 
buried material, both in the spring and fall as long as the temperature 
of the soil at a depth of 6 inches rises to 50 degrees Fahrenheit, for at 
least some part of the day. 
As a result of this movement to the surface, the recovery of larvae 
from 6 sets of burial experiments started September? to 9, 1921, from 
which there was an expectancy of at least 300 larvae, by November 
23rd totalled but 5 live larvae; practically the entire population having 
left the stalks. In the burials made as late in the season as October 19th 
there was practically no determinable active decrease throughout the 
balance of the season although a few larvae did move into the soil 
about the stalks where they were recovered. Likewise in burials made 
on the 11th of November no reduction of numbers of larvae was noted ( 
