44 
BULLETIN 1374, IT. S. DEPARTMENT OF AGRICULTURE 
A field that was heavily infested late in the fall was selected and on 
November 23, 2 square yards of soil to a depth of 6 inches were 
examined at each of five different points. An average of 5.2 living 
larvae per square yard were found in this soil. At the same time all 
bolls on the stalks growing on these 10 square yards of soil were 
removed and examined. There was a total of 122 dry and 50 green 
bolls, an average of 17.2 bolls per square yard, and these contained 
a total of 397 living larvae (first and second instars not included) r 
or an average of 39.7 per square yard. 
At near-by points in this field two areas of 50 square yards each 
were staked off on November 25 and the bolls both on the plants 
and on the ground were counted. On November 28 and. 29 the 
stalks were cut, and on December 1 they were raked up. On the 
following day the bolls on the surface of the ground in the same 
areas were again counted. The results are shown in Table 36. 
Table 36. — Number of bolls on stalks and on the ground on an area of 100 square 
yards, before and after cutting stalks 
Bolls 
Before cutting 
stalks 
After cutting 
stalks 
Percent- 
age shed 
On 
stalks 
On 
ground j 
On 
stalks 
On 
ground 
in cut- 
ting 
Green bolls _.- - ----- -.. .. .. .. 
108 
3 i 
1 77 
1443 
34 
733 
28.7 
Open bolls. 
986 ] 190 
55.1 
Total 
1,094 , 193 
i 520 
767 
52.5 
15.00 
59.6 
1 Calculated. 
This shows that nearly 60 per cent of all the bolls were left on the 
ground after the fields were cleaned, and that 28.7 per cent of the 
green bolls and 55.1 per cent of the open bolls on the stalks were shed in 
cutting the stalks. Using the percentage of 15 for bolls on the ground 
before cutting and the figure of 17.2 bolls on stalks per square yard 
already mentioned, at the time the soil examination was made on 
November 23 there were on an average 3 bolls per square yard on 
the surface of the soil at the points where these examinations were 
made. On November 25, 100 bolls collected from the surface of the 
soil showed an average of 2.12 living larvae per boll, which would 
make an average of 6.36 living larvae in bolls on the surface of every 
square yard of soil. On each of December 2 and 5,100 bolls were 
collected from the surface of the soil and examined, giving an average 
of 1.41 living larvae per boll. And on December 5 another square 
yard of soil was examined at each of the 5 points where examinations 
were made before, giving an average of 21.6 living larvae per square 
yard in the soil. Then using the figures obtained in these two soil 
examinations and the percentages given in Table 36, the distribution 
of larvae before and after the stalks were cut can be calculated. 
This calculation is summarized in Table 37. 
