128 
in more exposed situations, and the bollworm is thus able to develop 
with comparative freedom from these important natural checks. 
In the case of many insects affecting staple crops their best control 
is often to be found in the adoption of some chanoe in farm practice 
that will take advantage of some peculiarity in the life and habits of 
the pest. Such changes are usually quite in line with better farming, 
and involve no extra outla}^ of labor and money not warranted for 
other reasons than those of insect control. The bollworm falls easily 
into this class of insects, and the means which are of most importance 
in avoiding injury consist in certain changes in agricultural practice 
which are in themselves desirable, aside from their influence on the 
pest. 
Attention has elsewhere b'een called to the relation of the farm- 
ing methods in vogue to bollworm injury to cotton. Experiments dur- 
ing the past two years indicate that by improved cultural methods 
much ma}^ be done to insure a crop of cotton, even during years of 
severe bollworm injury. Detailed results of Held experiments have 
been given in Farmers' Bulletins Nos. 191 and 212. to which the reader 
is referred. The value of the so-called cultural method lies in the 
fact that cotton is not attacked in force until the field corn of the sur- 
rounding country, the favorite food of the bollworm, has begun to 
yellow and ripen and is no longer attractive to the moths for egg- 
laying purposes. The moths, therefore, concentrate in the cotton 
fields, obtaining their food from the nectaries on the squares and 
flowers of the cotton plant, and on these latter they deposit the bulk of 
their eggs. This time of migration to cotton will vary somewhat, 
depending on the relative earliness of surrounding corn, but will aver- 
age, one year with another, about the 1st of August, for the central 
and northern parts of the cotton belt. 
Another fact to be mentioned in this connection is the comparative 
immunity of the larger and maturer cotton bolls to attack b}' boll- 
worms, as compared with the smaller bolls and squares. This is indi- 
cated on page 72. These two circumstances in the natural histor}^ of 
the insect permit, by the use of improved cultural methods, of the 
production of a fair crop of cotton ahead of danger from bollworm 
injur}' in August. 
The importance of the early production of a maximum number of 
advanced bolls is therefore evident, and the cultural method involves 
the employment of all such means as will contribute to that end. 
such as — 
(1) Thorough plowing of land in the fall to destroy as many hiber- 
nating pupfe as possible. 
(2) The use of seed of earh^-f ruiting- varieties. 
(3) The use of fertilizers to hasten and increase fruit production. 
(1) Early planting in the sp^'ing. 
(5) Early and thorough cultivation. 
