SHARE OF INSECT CONTROL IN WEEVIL MORTALITV. 



29 



Table XVI. — A hypothetical average mortality of the boll weevil in square-retaining 



varieties.^ 



1 Given 10,000 weevil stages. 



Tliis series of tables, wherein the mortaUty of the weevil is given 

 an accurate basis for comparison, brings to light some very important 

 points. This is especially the case in Table XVI, wliich is based 

 upon the hypothesis that 50 per cent of the infested forms are hang- 

 ing. By comparing this hypothesis for the year 1908 >\-ith the 

 table of the same year in which it is considered that only 5 per cent 

 of the forms are hanging, it will be noticed that under the condition 

 of the greatest proportion of hanging squares the total control of the 

 weevil would be 52.39 per cent and the number of parasites to 10,000 

 weevil stages would be 1,154; whereas, with the smaller proportion 

 of hanging forms, the total control of the weevil would be 48.37 per 

 cent and the total number of parasites 634 to 10,000 weevil stages. 

 Now this shows a gain of 4 per cent in the actual control of the 

 weevil and almost double the number of parasites to 10,000 weevil 

 stages. Naturally, under such conditions it would follow that the 

 parasitic control would be even higher than that which has been used 

 as a basis for the estimate and would increase in rapid proportion. 

 In view of tliis showing of the fact that the larger the proportion of 

 hanging squares to the entire amount of infested forms, the larger 

 the insect control becomes, we recommend that those who are inter- 

 ested in the breeding of cotton varieties attempt to secure varieties 

 of cotton which \\'ill combine the necessary qualities of productive- 

 ness, length of lint, and early maturing wdth the square-retaining 

 tendency. It may be pointed out that the varieties known as Rublee 

 and Cook's Improved are not only conspicuous for the square-retain- 

 ing quaUties but also for their desirabihty under boU-weevil condi- 



