158 THE MEXICAN COTTON-BOLL WEEVIL. 



the growing of sprout cotton. As a check against this area, cotton 

 lands about 30 miles away were used. Here the stalks were not de- 

 stroyed in the fall, and the interpretation of the results of the experi- 

 ment was based upon a comparison of the number of weevils present 

 during the following season in the two localities. In May following 

 the destruction of the plants careful search revealed only one weevil 

 in the experimental area. In the check, however, the weevils were 

 so numerous at this time that practically all of the squares had been 

 destroyed. Examinations made later showed similar advantage in 

 regard to freedom from the boll weevil of the area where the stalks 

 were destroyed in October. The last examination was made on 

 August 20. At this time there were 10 sound bolls to the plant on 

 the experimental area and only 3 to the plant in the check area. 

 The difference in yield between the two areas was about 600 pounds 

 of seed cotton per acre. The work, therefore, resulted in an advan- 

 tage amounting to about $18 per acre. 



Newell and Dougherty 1 have described a very satisfactory device 

 for cutting the cotton stalks in the fall. It consists of a triangular 

 wooden framework, designed to pass between the rows and cut two 

 at the same time. In the process of cutting, the machine windrows 

 the stalks from two rows into the middle between the rows. The 

 runners are provided with knives made of sharpened metal. Old 

 saws have been found well adapted to the purpose. It is important 

 to provide a metal runner at the rear end of the machine to prevent 

 sliding. This runner is designed to run an inch or more beneath 

 the surface of the ground. The device can be made by any black- 

 smith at a cost of about $4. It will cut and windrow from 10 to 15 

 acres of stalks in a day. 



There is a disadvantage in cutting the stalks at or near the surface 

 of the ground : If warm weather follows, many of the roots will give 

 rise to sprouts that will furnish the weevils food. On this account 

 the process is less effective than uprooting the plants. Wherever 

 the stalk cutter is used, it should be followed by plows to remove the 

 roots from the ground. 



There is another important means by which the winter mortality 

 of the weevil may be increased. Tins is by removing the hibernating 

 quarters or destroying them after the weevil has gone into hibernation. 

 Many of the insects are to be found in the winter in trash and debris 

 found in and about cotton fields. The more shelter there is provided 

 in the form of weeds growing about the fields, the more favorable 

 the conditions will be for the insect. By the burning of such hiber- 

 nating quarters as are found in the cotton fields and in their immediate 

 vicinity a farmer can cut off a very large proportion of the weevils 

 that would otherwise emerge to damage the crop. 



The prolonged period of emergence from hibernation gives the 

 planter another important advantage over the weevil. It has been 

 shown on preceding pages that the period of emergence from hiber- 

 nation extends, in normal seasons, to practically the 1st of July. 

 In fact, except in one of the experiments that was performed, the 

 last weevils aid not appear until after the 20th of June. In the one 

 exception the last weevils appeared on the 6th of June. In Texas 

 it was found that 75 per cent of the emerging weevils appeared after 



1 Cir. 30, Louisiana Crop Pest Commission. 



