478 JOURNAL OF ECONOMIC ENTOMOLOGY [Vol. 17 
occurred either within two weeks before migration or after the begin¬ 
ning of migration. 
Factors Influencing Tests. —Serious weevil infestation did not 
occur in the majority of the plots until August 10th, or later. It was 
necessary to poison only one field used in these tests prior to August 9th. 
Several plots selected to be used in these tests never required poisoning 
because the crop matured before weevil injury developed. 
The number of poison applications required is determined by the per¬ 
centage of infestation and the fruiting condition of plants. No applica¬ 
tions of poison were made when weevil infestation was low or when the 
plants were not fruiting. 
Cotton on fertile land that continued fruiting over a long period, 
offered the best opportunity for securing increase in yield, as a result of 
poisoning. The crop was late in localities, where tests were conducted, 
affording an excellent opportunity for testing the value of poison appli¬ 
cations after the beginning of weevil migration. 
Seasonal Progress of Infestation. —Infestation records were 
made weekly, throughout the growing season. Before square forma¬ 
tion the weevil infestation was determined by counts of the number of 
weevils per hundred plants. After square formation the weevil infesta¬ 
tion was determined by counting the percentage of squares infested. A 
summary of these records is given in tables 1 and 2. The plots used in 
these experiments varied in size from three-quarters of an acre to 3>^ 
acres, no poison applications having been made on these plots, prior to 
the date records were begun. It is believed that these records will in¬ 
dicate, why early poisoning did not usually give profitable results in 
the localities under consideration. 
Table 1. Plant Infestation Records 
Date Percentage Number of Plots 
examined 
June 12_:. 1.19 11 
June 18. 0.9538 21 
June 25. 1.23 21 
July 3. 0.9966 12 
July 9. 0.7012 8 
Table 2. Square Infestation Records 
Date Percentage Number of Plots 
examined 
July 9. 4.823 7 
July 16. 3.937 28 
July 24. 2.876 29 
August 1. 3.467 24 
August 8. 2.382 29 
August 15. 17.656 20 
August 22 . 24.296 13 
