In a recent webinar hosted Dr Rob Beresford of PFR shared interim findings from his research into non-synthetic fungicide options for controlling myrtle rust.
Funded by MPI, the study involved glasshouse and field trials using a range of alternative products on the highly susceptible cultivar Lophomyrtus 'Red Dragon'. Each treatment was assessed for both efficacy in preventing infection and any adverse effects on plant health (phytotoxicity).
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While synthetic fungicides continue to be the most effective solution, some alternative options have shown promising results. Copper-based fungicides, including oxide, oxychloride, and hydroxide, as well as sulphur, provided moderate protection against infections with minimal phytotoxic effects on plants. Sodium bicarbonate at a 5% concentration was somewhat effective in preventing infections; however, it caused severe plant damage, such as shoot dieback and suppressed growth. Lower concentrations of sodium bicarbonate and potassium-based products, like bicarbonate and silicate, were less effective and still exhibited moderate to high levels of phytotoxicity.
A full report is due next month, after which NZPPI will update the Myrtle Rust Prevention with Fungicides protocol to reflect the latest science.
For more information:
New Zealand Plant Producers Incorporated
nzppi.co.nz