Infestations in control fields Ik, l5j and l6 were not recorded 

 until late in July. 



The yields of lint cotton per acre from the total acreage under treat- 

 ment, with the exception of fields 2 and h, were determined from local gin 

 records. Accurate records from fields 2 and h were not available. 



Records were also kept of the rainfall in each of the l6 field samp- 

 ling areas during the treatment period, as well as the amounts of ferti- 

 lizer per acre applied by the cooperating growers. 



Two spring (I96I, 1962) and one fall (1961) woods trash examinations 

 were made to compare numbers of weevils in hibernation within the treat- 

 ment area with those in the surrounding areas. 



Results.- The data from all fields are summarized in tables 1, 2, 

 and 3. Detailed records from several fields representative of those re- 

 ceiving four different treatment schedules are presented as follows: (l) 

 Highest and lowest yielding fields (3 and 5) which received five early- 

 season, plus four or five late-season applications, table I4.J (2) highest 

 and lowest yielding fields (11 and 12) which received five early-season, 

 plus one late-season application, table 5; (3) field 13, which received 

 fifteen continuous dust applications from June II4 to August 22, table 6; 

 and (U) field l5, which received one insecticide application on July 26, 

 table 7 . 



Pretreatment overwintered boll weevil populations ranged from to 

 169 per acre. After treatment began, weevil movement from hibernation 

 sites into the treated area could not be accurately determined by field 

 examinations because of the effectiveness of the control program. How- 

 ever, some indication of the numbers of weevils entering the fields can 

 be obtained from records of field 13 (table 6) where four applications 

 of Sevin dust and two applications of BHC plus DDT dust were made between 

 June ll; and July 10. Weevil populations ranged from kk to 133 per acre 

 with an average of 8I for the emergence period. 



After early-season treatments were completed, periods ranging from 

 23 to 14.6 days, with an average of 36 days, elapsed before a ten-percent 

 boll weevil infestation of squares occurred in the various fields. How- 

 ever, most growers had made one or more late -season applications before 

 this time. The intervals during which insecticides were not applied ranged 

 from 2l| to 52 days, with an average of 36. It is generally believed that 

 cotton grown in this area should receive treatment in the early fruiting 

 period before infestation reaches the 10-percent level if maximum yields 

 are to be realized (Bondy, 1939). It appears, however, that for determin- 

 ing the starting time for the series of late-season applications follow- 

 ing early-season treatments, a lower- infestation figure from 3 to 5 

 percent should be used. 



Some growers, because of inadequate use of fertilizer, could not 

 justify late-season, boll-weevil-control treatments. Others applied a 

 series of late-season treatments of Guthion plus DDT which were only 

 partially effective because of low application rates and extended appli- 

 cation intervals. These intervals ranged from h to ik days with an 

 average of T.U days. Thus, in fields 6 through 12, where one or two 

 late -season applications were made at 10- to lU-day intervals, and in 

 control fields Ik, l5, and 16^ where one to four late-season applications 



-If- 



