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Microwave radiation reduces survival of Fusarium pseudograminearum in infected durum wheat stubble

Toni Petronaitis: Department of Primary Industries (DPI)

<div><em>Fusarium pseudograminearum </em>(<em>Fp</em>) is a stubble-borne fungus 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 <em>Fp</em> inoculum levels in these residues. Crown and node sections (15 mm) of durum wheat stubble infected with <em>Fp</em> collected post-harvest 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 <em>Fp</em> 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 <em>Fp</em> to an average of 69 %, 46 %, 30 % and 19 % of stubble sections, respectively, compared to the control (72 %). Efficacy was improved by embedding stubble segments in moist soil, where microwaving for 15, 30, 60 and 120 s reduced recovery of <em>Fp</em> to an average of 34 %, 0 %, 1 % and 0 % of stubble sections, respectively. Although microwave radiation significantly reduced the survival of <em>Fp </em>in durum wheat stubble in the laboratory, the practicality of this method for crown rot management under field conditions is yet to be established.</div>