Intratree Dispersal of the Pecan Weevil 12

Abstract

A study was conducted on the intratree dispersal of Curculio carvae (Horn) in 4 pecan trees about 35 ft high. For 4 consecutive days in August, 66 pecan weevils were released at each of 3 height levels (top = 35 ft, middle = 20 ft, and lowest limbs = 5 ft) of one quadrant of the 4 trees, starting with the north side of the tree and rotating clockwise each successive day. Weevils totaling 3168 were marked and released in this experiment: 198 weevils per quadrant (66 weevils for each of the 3 height levels) and 792 weevils per tree on each of the 4 trees. On the fifth day after the weevils were released in the first quadrant, recapture of the weevils was accomplished by jarring the lower half of the tree and by using a modified crane and platform for the upper portion of the tree. Approximately 10% of the marked weevils were recovered by the mechanical recapture method, and 7% by using insecticide after mechanically harvesting the weevils from the trees. Our study indicated that weevils move considerably in a tree—from the top of the tree to the lowest limbs and from the lower heights to the upper portion of the tree, as well as around the tree. The significance of dispersal of the pecan weevil to possible control measures is discussed.