squares removed were increased. Fewer bolls were required to make a pound of 

 seed cotton on the treated plots than on the check. When the bolls were protected 

 from weevil damage, the decrease was 9 or more bolls per pound on those plots 

 that had all of the squares removed after the 7th week of square production. 



The highest average yield the first year was made by plots that had 10% of 

 the squares removed the first week of square production, increased by 10% each 

 week through the 5th week to 50%, and held at that level for the remainder of the 

 season. The greatest loss from this treatment in August of 1 of 3 years was 5.5%. 

 Plots that had the percentage of squares removed increased to 40 the 4th week 

 and held at that level for the remainder of the season, exceeded the yield of the 

 check 2 years, and yielded within 1 percent of it the 3d year. 



The average percentage of locks lost on bolls was 1.05% in 1939 and 1.1% in 

 1942 for each percentage of weevil infestation on the day the bolls were marked 

 as blooms. A very high weevil infestation that developed within a short time, late 

 in the season of 1940, caused severe damage to bolls set on cotton that had been 

 delayed in fruiting by a flood. 



Exclusive of a few bolls set very early and late in the season, 4 varieties of 

 cotton set approximately 80% of the crop during the 1 st 5 weeks of fruiting and 

 over 70% during the 2d, 3d, 4th, and 5th weeks. 



1959 - Gaines, R. C. Ecological investigations of the boll weevil, Tallulah, La., 1915- 

 1958. U. S. D. A. Tech. B. 1208, ARS, 20 p. Sept. 



Ecological and attractancy studies on the boll weevil were conducted at 

 Tallulah, La., during the period 1915-1958. Records on winter survival in Spanish 

 moss were made from 1916 to 1940 and in ground trash from 1937 to 1958. 



Temperatures below 20°F. -were fatal to most of the weevils hibernating in 

 Spanish moss. Survival from ground trash was more closely related to the num- 

 ber of weevils in the field during May and June. Hibernation cages did not pro- 

 vide a reliable estimate of winter survival. High correlations were found between 

 winter temperatures, weevil survival, summer rainfall, and cotton yields. The 

 insect was more tolera,nt to calcium arsenate late in the season than earlier. 



Longevity records of 690 overwintered weevils during the period 1934-58 

 showed that some live longer than 383 days. Flight screen studies showed that 

 8-mesh hardware cloth, coated with a mixture of tanglefoot plus 37^% of castor 

 oil on a stationary wooden frame, the bottom of which was 3 feet from the ground, 

 provided a satisfactory method for collecting the boll weevil and other insects in 

 flight. Screen direction had little effect on the total number of insects caught. 

 Studies with revolving screens, which at all times faced the wind, showed that 

 more boll weevils were taken on the leeward side. A greater number of insects 

 were taken on screens 3 feet above the ground than at higher altitudes. Boll 

 weevils became active during the hibernation period and took to flight when the 

 temperature reached or exceeded 62°F. Chemotropic studies of trimethylamine 

 and ammonium hydroxide on flight screens indicated that these chemicals had 

 some attraction for the boll weevil in the absence of cotton. 



EFFECT OF WEATHER 



1908 - Sanderson, E. D. The influence of minimum temperatures in limiting the 



northern distribution of insects. J. Econ. Ent. 1:261. 



The apparent killing out of the weevil in certain sections by low winter tem- 

 peratures. 



1909 - Hunter, W. D. Boll weevil situation in Oklahoma. Okla. State Bd. Agr. Mo. Press 



B. 7, p. 2-3. Sept. 1. 



A statement regarding the scarcity of boll weevils in Oklahoma due to the 

 heat and drought. The early fall destruction of stalks is urged so as to take ad- 

 vantage of the natural setback the weevil has received. 



136 



