Pecan weevil movement within the orchard

Authors: Cottrell, Ted; Wood, Bruce

Submitted to: Pecan Grower
Publication Type: Trade Journal
Publication Acceptance Date: 3/28/2007
Publication Date: 5/25/2007
Citation: Cottrell, T.E., Wood, B.W. 2007. Pecan weevil movement within the orchard. Pecan Grower. 28(4):30-36.

Interpretive Summary: The pecan weevil is an indigenous pest of pecan in North America. Movement by adults, emerging from the orchard floor, to the pecan tree and movement within and between trees is poorly understood. Knowing this information is key to the implementation of alternative management strategies that seek to exploit pecan weevil behavior. Additionally, no information exists on daily activity patterns for the pecan weevil movement. In this study, both male and female weevils were just as likely to be captured by any of four different trap styles used. More pecan weevils were found to crawl to the trunk than fly and a proportion of the population flies directly into the pecan canopy. In three of four years, adult pecan weevils were vertically distributed similarly throughout the pecan canopy and most pecan weevils captured in flight were from the highest traps suspended between trees. It was found that pecan weevils move from the orchard floor to the pecan tree near dusk.

Technical Abstract: The pecan weevil, Curculio caryae (Horn) (Coleoptera: Curculionidae), is an indigenous pest of pecan, Carya illinoensis Wang K (Koch) in North America. Movement by adults, emerging from the orchard floor, to the pecan tree and movement within and between trees is poorly understood. Additionally, no information exists on diel periodicity of pecan weevil movement. In this study, no interaction of trap location*gender was found for pecan weevils using any of four different trap styles. More pecan weevils were found to crawl to the trunk than fly and a proportion of the population flies directly into the pecan canopy. In three of four years, adult pecan weevils were vertically distributed similarly throughout the pecan canopy and most pecan weevils captured in flight were from the highest traps suspended between trees. In addition, this is the first report on the diel periodicity of movement by pecan weevils from the orchard floor to the trunk where it was found to be a predominantly crepuscular event taking place at dusk.