397 



778. ; Taft, H. M.; Ray, L.; and Hopkins, A. R. 1971. Population dynamics 

 of the boll weevil in an isolated cotton field in South Carolina. Ann. 

 Entomol. Soc. Am. 64: 394-399. 



In 1968 and 1969, the rate of increase of a population of Anthonomus grandis 

 Boheman was observed in a small cotton field isolated from other cotton plant- 

 ings by distances of 14-26 miles. Wing traps baited with unmated male boll 

 weevils were used to study the size of the population and the movement of 

 weevils in the area around the field. In both years, the population increased 

 to destructive levels within the period of F^ adult emergence, and 80-90% of 

 all developing cotton fruiting structures were continually destroyed when the 

 population was 2000 or more per acre. The wing traps captured 85% of the emerging 

 overwintered weevils but were ineffective in controlling later generation weevils. 

 Traps placed away from the field revealed extensive immigration of F,, F„ , and F, 

 weevils into the area, apparently from distant cotton fields. 



779. , and Walker, J. T. 1970. A parasitic mite found on boll weevils near 

 Florence, South Carolina, in 1968. J. Econ. Entomol. 63: 646-647. 



Overwintered boll weevils captured in pheromone traps were parasitized by larval 

 mites ( Leptus spp.). Up to 50% of collected weevils had mites attached. No 

 measures were made of the debiliting effects of the mites on the weevils. 



780. Robertson, 0. T.; Noble, L. W. ; and Orr, G. E. 1966. Spread of boll 

 weevils and its control in far west Texas. J. Econ. Entomol. 59: 754-756. 



The boll weevil, Anthonomus grandis Boheman, became established in the Presidio 

 Valley of Texas in the early 1950' s. Robertson reporting on the infestation 

 through 1955, showed that the insect first became established in the eastern 

 end of the valley and moved aorthward to Candelaria. The western boundary of 

 the infestation in 1955 was about 75 miles below the El Paso Valley, which com- 

 prises a strip of irrigable land along the Rio Grande in Hudspeth and El Paso 



(page 399 follows) 



