Location: Fruit and Tree Nut ResearchTitle: Factors affecting pest abundance in the orchard
Submitted to: Pecan South
Publication Type: Trade Journal
Publication Acceptance Date: 5/12/2021
Publication Date: 6/1/2021
Citation: Cottrell, T.E. 2021. Factors affecting pest abundance in the orchard. Pecan South. 54(4):8-15.
Technical Abstract: Insect pest abundance in pecan orchards is affected by both bottom-up and top-down regulation of the pest herbivores. Bottom-up population regulation is mediated via the host plant and can include defensive plant chemistry negatively affecting herbivore performance. Top-down population regulation is mediated via natural enemies preying on the pest herbivores. In pecan orchards, both bottom-up and top-down examples of herbivore regulation are available. Certain pecan cultivars exhibit more/less black pecan aphid feeding injury across the season due to variable levels of plant bioregulators inhibiting normal feeding activity of the aphid. The black pecan aphid survives at low population densities through much of the season until levels of plant bioregulators naturally decrease thus allowing 'normal' aphid growth. Regardless of the time of year, the black pecan aphid is susceptible to numerous natural enemies. However, defensive behavior by the black pecan aphid using enemy-free space on the upper side of pecan leaves allows a proportion of the population to avoid predation.