131 



residual kill for 4-6 hours; at 2 lb per acre it was effective for more than 

 24 hours. 



243. Fye, R. E. 1968. Populations of boll weevil in selected fields in Arizona 

 in 1965 and 1966. J. Econ. Entomol. 61: 377-380. 



Surveys of boll weev-Is, Anthonoraus grandis Boheman, in selected cottonfields 

 in Arizona in 1965 and 1966 indicated infestations of the boll weevil were 

 widespread. Populations were greater in 1965 than in 1966, and larger popu- 

 lations occurred in stub cotton than in planted cotton. The boll weevil 

 complex in cultivated cotton in Arizona attacks bolls throughout the season. 

 Large populations of potential overwintering weevils in bolls were destroyed 

 with stalk shredders and clean plowing. 



244. . 1968. Spread of the boll weevil by drainage water and air currents. 

 J. Econ. Entomol. 61: 418-424. 



When conditions are ideal, the thurberia weevil, Anthonorous grandis 

 thurberiae Pierce, may be moved in thurberia bolls in flood drainage water 

 from the mountainous areas where thurberia grows into the valleys where 

 cotton is cultivated. However, the necessary conditions seldom occur. 

 Tests in the laboratory indicated that vertical air velocltites of 2.5-5.5 

 meters per second are necessary to suspend passive boll weevils, A. grandis 

 Boheman, and that velocities in excess of 31.3 meters per second may be 

 needed to free a weevil from its foothold on cotton leaves. In the later 

 summer in Arizona and northern Sonora, Mexico, the necessary air turbulences 

 (thermal convection and dust devils) are present to elevate boll weevils 

 into the upper wind currents. Then these upper wind currents and their 

 associated turbulences could move the weevils in the direction of the airflow. 



