Microwave radiation reduces survival of Fusarium pseudograminearum in durum wheat stubble

Abstract

Fusarium pseudograminearum (Fp) is a stubble-borne fungal pathogen which is the main causal species of the disease crown rot across the Australian wheat-belt. Microwave radiation may offer a rapid and chemical-free approach to reduce Fp inoculum levels in cereal residues. Crown and node sections of durum wheat stubble infected with Fp collected from an inoculated field experiment were microwaved using a conventional 1100 W microwave oven for 0, 15, 30, 60 and 120 s either embedded in moist soil or without soil. The survival of Fp after microwave radiation was assessed by culturing on 1/4 PDA plus novobiocin. Microwave radiation for 15, 30, 60 and 120 s without soil reduced recovery of Fp to an average of 69%, 46%, 30 and 19%, respectively, compared to the control (72%). Efficacy was improved by embedding stubble segments in moist soil, with recovery of Fp reduced to an average of 34%, 0%, 1 and 0% when microwaving for 15, 30, 60 and 120 s, respectively. Although microwave radiation significantly reduced the survival of Fp in durum wheat stubble in the laboratory, the practicality of this method for crown rot management under field conditions is yet to be established.