﻿STUDIES OF THE PINK BOLLWOEM IN" MEXICO 



41 



Table 31. — Temperature, in degrees Fahrenheit, on surface of, and in, soil between 



cotton roios in the field 



Date 







1 inch 



Hour 



Sm-face 



beneath 

 surface 





O J. 



O J- 



12.30 p.m. 



142 



124 



2.30 p.m. 



141 



123 



4.30 p.m. 



123 



116 



10.00 a.m. 



128 



101 



12.30 p.m. 



146 



115 



2.30 p.m. 



138 



124 



4.30 p.m. 



114 



112 



10.30 a.m. 



128 



102 



12.30 p.m. 



141 



114 



2.30 p.m. 



130 



112 



2 inches 

 beneath 

 surface 



Maxi- 

 mum air 

 temper- 

 ature 



1921 

 Sept. 13..- 



Sept. 14 



Sept. 15 



113 



op 



112 



108 



95 



9? 





106 

 111 



96 



nn 





94 





102 

 102 



92 



A temperature suJfficient to kill the pink boUworm in a very short 

 time is reached on the surface of the soil, and the soil, even as deep 

 as 1 inch below the surface, becomes hot enough on some days to kill 

 in time. All these readings were taken between the cotton rows, 

 where the soil was exposed to the direct rays of the sun. 



Early in the morning of September 14, infested blooms were placed 

 in and on the surface of the soil in direct sunlight and in the shade of 

 cotton plants. These blooms had been collected from plants and 

 allowed to dr;^ several days in the laboratory. Ten blooms, each 

 containing a living larva, were used in each experiment. Late in 

 the afternoon the blooms were removed and examined. The results 

 are given in Table 32. 



Table 32. — Effect of solar heat on pink bollworm larvae in blooms in and on the 

 surface of soil in sunlight and in shade 



Location 



Sunlight 



Shade 



On surface 



10 dead larvae .. 



4 live larvae, 6 empty blooms. 



2 inches beneath surface. . 



6 live larvae, 4 empty blooms 



5 live larvae, 5 empty blooms 



7 live larvae, 3 empty blooms. 



4 inches beneath surface 









All larvae on the surface in the sun were killed. All larvae in the 

 other locations either lived or left the blooms. The maximum air 

 temperature on this day was 96° F. 



A similar experiment was conducted a few days later with pupse in 

 blooms. After exposure the pupae were removed and placed in vials 

 so that emergences of moths could be noted. The results are given 

 in Table 33. 



Table 33. — Effect of solar heaton pupx in shed blooms in and on Uis swr/aje of the 

 soil in sunlight and in shade 





Sunlight 



Shade 



Location 



Total 

 pupse 



Moths 

 emergod 



Total 

 pupae 



Moths 

 emerged 





14 

 13 

 12 





 10 



u 



14 

 Tost oral 







2 inches beneath the surface . . ——...... 



ttod. 





Tost oral ited. 









