Spatiotemporal activity of pecan Auchenorrhyncha reflects complex interactions with canopy management

Abstract

In perennial agroecosystems, pest management outcomes are influenced by herbivore ecology and farming practices that shape arthropod activity. Yet, across many systems, information on taxonomic composition, spatiotemporal dynamics, and sensitivity of herbivore groups to crop management is sparse. In perennial tree crops, Auchenorrhyncha (Hemiptera) are abundant herbivores, notable for causing feeding damage and transmitting plant pathogens. Here, to strengthen the ecological understanding of Auchenorrhyncha activity in managed tree systems, we tracked the seasonal abundance and within-canopy distribution of Auchenorrhyncha in a mature pecan ( Carya illinoinensis ) orchard over two seasons and evaluated how these patterns interact with common canopy management interventions: hedge pruning and calendar-based pesticide applications of insecticide and fungicide. We collected 5882 Auchenorrhyncha, representing seven families. The assemblage was dominated by Cicadellidae, with over 95% of individuals belonging to the subfamily Typhlocybinae. Auchenorrhyncha abundance increased from June to September, and the lower canopy consistently harbored fewer insects. Calendar-based pesticide applications reduced community abundance, although effects varied across dates and canopy location, highlighting potential spatial constraints of pesticide use in tall trees. In contrast, hedge pruning significantly increased Auchenorrhyncha abundance, independently of pesticide use or canopy location. This study not only establishes a baseline for the taxa composition and spatiotemporal activity of Auchenorrhyncha in pecan systems but also advances our understanding of how common farming practices interact with herbivore community patterns. Together, these findings support the refinement of more ecologically grounded, spatially informed strategies for pest management in pecan and other tree-based systems.

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