Of the 1,895 acres in the treatment area, 1,796 (fields 1 through 

 12) were treated with a Guthion emulsion spray at 0.25 pound per acre or 

 Guthion at 0.25 plus DDT at 0.5 pound per acre. All of these fields 

 received five early-season treatments except fields 6 through 9, which 

 received only four. Each field received two treatments that included 

 DDT. The 12 fields also received from one to five late-season appli- 

 cations . 



The 99 acres (field 13 ) not treated with Guthion were treated with 

 Sevin and BHC-DDT dusts on a continuous application schedule. The Sevin 

 was applied at 0.75 or 1.13 pounds per acre and the BHC-DDT at O.I4.5 plus 

 1.5 or 0.5 plus 2.0 pounds per acre. In this field, five treatments were 

 applied during the early season, and ten from July 10 to August 22. 



The three control fields, totaling 32 acres, did not receive early- 

 season treatments. The first (field llj.) received three late applica- 

 tions of toxaphene dust at 2.0 pounds per acre on July 8, I6, and 

 August 3- The other two (fields l5 and I6) were treated with Guthion- 

 DDT at 0.25 plus 0.5 pound per acre; field l5 received a single late 

 application on July 26, and field I6, four applications on July 17, 2l|., 

 31, and August 8. 



The spray applications were made at rates ranging from 3-25 to 5-33 

 gallons per acre. Tractor-mounted and high-clearance, self-propelled 

 sprayers, equipped with three nozzles per row or broadcast spray booms, 

 were used to apply the insecticides. The dust was applied at various 

 rates with tractor-mounted dusters; and in control field II4., dust was 

 applied by the "hand-sack" method. 



Boll weevil and bollworm infestation records within the treated 

 area were obtained from I6 field sampling areas varying in size from 

 1.3 to 8 acres. The total area sampled was 87.3 acres. 



To determine adult weevil populations prior to squaring, 50 con- 

 secutive plants at 10 randomly selected points per acre in each sampling 

 area were examined After square production started, the number of 

 adults present was determined at the same time that the larval infesta- 

 tion examinations were made. 



To determine the magnitude of weevil and bollworm infestations from 

 June Ik to July 6, all squares of puncturable size {^ nan. or larger in 

 diameter) on 10 plants at 10 randomly selected points per acre were 

 examined in each of the I6 individual sampling areas. Thereafter, 

 because of the rapidly increasing numbers of squares, all squares on 5 

 plants at 10 randomly selected points per acre in each sampling area were 

 examined. Infestation percentages were based on the total number of 

 squares punctured. Since many squares were punctured more than once, 

 these percentages do not reflect the total number of oviposition and feed- 

 ing punctures. The number of plants per acre in each field from which 

 records were taken was used to calculate weevils and punctures per acre. 

 Significant bollworm populations did not develop in any of the fields 

 under examination, and these records are not included in the data. 



-3- 



