94 



that the procuring of the immediate- crop is the only desideratum. 

 Early and complete destruction of stalks is undoubtedly the most 

 important single element insuring success for the subsequent year. 



DISSEMINATION. 



Two principal periods of dissemination may be found during a sea- 

 son. The first is when the hibernated weevils leave their winter 

 quarters and go in search of food. Having found food, the spread is 

 mainly controlled by the limitation of the food supply. So long as 

 an abundance of growing tips or of clean squares is near at hand 

 weevils will not travel far, but when the condition of total infestation 

 is reached the period of greatest dissemination is also attained. 



In any given field dissemination takes place mainly by the short 

 flights and crawling of the weevils. The search of the female for unin- 

 fested squares is the principal factor in their movement. Heavy 

 winds seem to be of comparatively small importance, as weevils do 

 not take flight readily at such times; but light, warm breezes, such as 

 prevail throughout the coast country of Texas, undoubtedly tend to 

 carry them in a general northerly direction, and the continuous equi- 

 noctial storms of the fall in Texas, occurring at the very time the 

 pests are most active, have undoubtedly had a strong effect in the 

 same direction. 



The two principal lines of spread will be found along railways and 

 water courses. Between localities separated by short distances, traffic 

 along highways is probably the chief factor. The distance which a 

 weevil may travel in flight has never been determined, but from a 

 study of their habits of flight it would seem to be comparatively short. 

 Floods and the motion of water along water courses frequently serve 

 to distribute many weevils along the edge of high- water mark. As 

 river valleys are largely devoted to cotton culture, this would seem to 

 be no small factor in the transportation of the weevils. 



Over longer distances the usual means of commercial traffic must 

 be held responsible. Shipments of cotton, whether for ginning or in 

 baled condition, are likely to carry many weevils. Shipments of seed 

 for planting, coming from infested localities, are almost certain to 

 carry weevils, and shipments of seed to oil mills may also assist in 

 scattering them. The pests are often carried far outside of infested 

 regions in the shipment of seed to northern oil mills. From the mills 

 they are carried to the farms in the hulls or other by-products used 

 for feeding cattle. Many of the isolated colonies in northern Texas 

 originated in this manner. 



WEEVILS IN SEED HOUSES AT GINNERIES. 



Careful observations made by Mr. Schwarz at Victoria throughout 

 the winter of 1901-2 revealed great numbers of weevils about the gins. 

 They occurred especially in the seed houses, and the danger of the 



