Evaluation of a new DNA tool to detect Phytophthora in paddocks

Abstract

Key findings • Knowledge of Phytophthora medicaginis (Pm) DNA concentration in soil can assist Phytophthora root rot (PRR) management. • In a field trial, treatments with 0 and 100 oospores/ plant resulted in low Pm DNA concentrations a month after sowing and had significantly less disease development and significantly higher yields than Treatments with higher oospore concentrations at sowing in 2014. • Similar PRR disease levels and yield losses resulted from medium to high Pm soil inoculum concentrations at sowing in the Pm susceptible chickpea variety Sonali. • The Pm DNA test is capable of identifying Pm in soil samples collected from grower paddocks across the northern region. • Pm DNA results and Pm isolation results agreed for most paddock samples with 82% of positive and 97% of negative samples being consistent. However, results for three samples indicate that further work is required to address some issues including potential sub‑sampling effects.