﻿8 BULLETIN 1374, U. S. DEPARTMENT OF AGEICULTUEE 



stages being found immediately under the plants and only 32.9 per 

 cent between the rows. 



Table 5.- 



—Total larvse, 



-pupse, 

 the 



and pupal cases found in the soil immediately under 

 row and between the rows 



Date 



Under 

 the row 



Between 

 the rows 



Aug. 19—.-- 







1921 



60 

 69 

 18 

 33 

 9 



18 

 28 

 27 

 6 

 13 



55 



Sept. 6.-- 



11 



25 „ 



6 



Oct. 18 . 



10 



29 - 



10 



Mar. 23 







1922 



1 



Do - - 



16 



Do 



19 



Do 



4 



Do - - 



6 













Total 



281 

 67.1 



138 



Percentafffi of total 



32.9 













RESTING-STAGE LARV^ IN THE SOIL 



Not only does the larva of the pink boUworm, in the Laguna dis- 

 trict, go to the soil- during the summer for transformation into the 



Fig. 4. — Cocoons spun by the pink bollworm in the soil. Top row shows type of summer cocoons and 

 bottom row type of winter cocoons 



adult, but to a certain extent it also passes the winter there in the 

 resting stage. The summer larva, after entering the soil, spins a 

 light oblong cocoon in which it pupates. Later, in the fall, some 

 cocoons of a much heavier texture and more spherical in form are 

 noticed in the soil (fig. 4) . In these the larvse are found in the same 

 characteristic curled-up position that they assume on passing the 

 winter in double seeds. Observations have shown that when dis- 

 turbed, unless it is unusually cold, the larva readily leaves this cocoon. 

 In Tables 6 and 7 are given the results of all the soil examinations 

 made in 1921 and 1922 cotton fields. The maximum number of 

 living stages found at any time is shown in the second examination of 

 1921 when a total of 83 living larvse and pup^ were found in 1 square 

 yard of soil. This sample was taken from a heavily infested field of 

 very large cotton on loose sandy soil. 



