ASABE Technical Library - Abstract

Abstract.

Armillaria root rot, caused by the fungi Armillaria tabescens and Armillaria mellea, is a major cause of premature tree death in peach orchards in the southeastern United States. Starting from the soil, the pathogen infects and colonizes the root system and then the collar at the base of the tree, resulting in tree decline and death. Due to the long asymptomatic period of the disease, it is challenging yet critical to find a way to detect emerging infections at an early stage to enable timely interventions and the prevention of widespread tree death. We have investigated and identified chemical markers that are associated with pathogenic Armillaria. Based on GC/MS analysis of the volatile organic compounds (VOCs) emitted by the pathogen, a representative VOC signature of the disease was established. VOCs were collected from the headspace of Armillaria cultures and from infected peach trees in an orchard. In addition, the time course of VOCs produced by Armillaria cultures was investigated. We documented intensity variation of specific VOC compounds, which could serve as an indicator of peach tree health status. The results obtained with this VOC-based disease detection method have laid the foundation for the development of a field-deployable Microelectromechanical system Gas Chromotography (MEMS-GC) sensor for rapid and early plant disease detection in agriculture.