BOLL- WEEVIL COTTON IN TEXAS. 17 



most of the flower buds are destroyed, the plants grow -more vigor- 

 ously, attain a larger size, and show a deeper green color than in 

 normally productive fields. Large numbers of sterile, defective in- 

 volucres', lacking the essential organs of normal cotton flowers-, are 

 produced on boll-weevil cotton in the latter part of the season. 



As a result of the more luxuriant growth of boll-weevil cotton, 

 the fields are soon covered with a dense mass of foliage, the lanes are 

 closed between the rows, and the ground is shaded continuously. 

 Under such conditions the weevils breed in large numbers and there 

 is no prospect of producing a crop. Weevil larvse in fallen buds are 

 protected by the shade of the overgrown plants instead of being 

 killed by exposure to heat and dryness. t 



Seasonal conditions at San Antonio, Tex., in 1921, afforded defi- 

 nite contrasts and illustrations of the limiting factors of cotton pro- 

 duction in the presence of the boll weevil. The insects were so 

 abundant that most of the flower buds were destroyed, though other 

 conditions were favorable for the growth of the plants and the pro- 

 duction of a large crop of cotton. 



After the plants had grown large and reached the condition of 

 boll-weevil cotton, the heavy foliage and continuous shading of the 

 ground protected the weevils, even during dry weather. Thus, the 

 normal advantages of dry weather in restricting weevil injury were 

 completely lost in the fields of boll-weevil cotton, and very few bolls 

 were produced. But many late-season bolls were matured on indi- 

 vidual plants and open rows that stood apart, even for a few feet, 

 from the boll-weevil cotton. 



The behavior of well-fruited open plants, contrasting with that 

 of sterile crowded plants, shows the necessity of avoiding the rank 

 growth and dense shade conditions of the boll- weevil fields. The 

 setting of many late bolls on exposed individual plants and open 

 rows of cotton shows how strictly the insects, during periods of dry 

 weather, are dependent upon the protection afforded by the boll- 

 weevil cotton and teaches the necessity of avoiding the rank growth 

 and continuous shading of the fields. The advantage of cultural 

 methods that will keep the lanes open between the rows is clearly 

 indicated. 



Wider separation of the rows, combined with closer spacing of 

 the plants in the row, is a wa} 7 of restricting the size of the individual 

 plants, keeping the lanes open between the rows, and avoiding the 

 adverse condition of boll-weevil cotton. Experiments have shown 

 that wider rows with closer spacing of plants in the rows is a prac- 

 ticable method of culture and likely to have advantages in dry sea- 

 sons as well as in years of boll- weevil cotton. 



Though further tests and experiments are needed to determine 

 the best arrangements of rows under different local conditions, the 

 indications are that the rows should not be less than 4 feet apart 

 and the plants should not be more than 6 inches apart in the rows 

 to give the best assurance of suppressing the secondary stalks, keep- 

 ing the lanes open between the rows, and avoiding boll-weevil cot- 

 ton. As an emergency measure, in the absence of other precautions 

 in spacing, the cutting out of alternate rows might be advisable as 

 a means of avoiding the condition of boll- weevil cotton, as shown 



