Phytoplasma in mungbeans—Update: early March 2018

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Phytoplama has been reported in second flower flushes in mungbeans, and also in harvested mungbean regrowth!

So far the overall incidence of phytoplasma has been lower than this time last year, but growers and consultants are urged to keep monitoring their crops for the first symptoms of this disease, and to report any outbreaks. Many January-planted mungbean crops are at early flowering/podding; the crop stage at which phytoplsama is often first noticed.

Phytoplasma reports are coming in from some districts on the Darling Downs in earlier-planted crops that have put on a second flush of flowers/pods following recent rains. While the level of infection is still low (at 1-2%), symptoms are still quite noticeable.  Similar second flush outbreaks were observed in November 2017 at Mareeba, NQ.

Phytoplasma in mungbeans with a second flush of flowers. Photo by Tony Matchett, Tableland Fertilizers, Mareeba.

One unusual report has been in post-harvest mungbeans (see image below) at Warra, where phytoplasma symptoms were observed in 10% of regrowth from the standing mungbean stubble. As these infected plants are a potential source of infection for surrounding mungbean crops, this post-harvest crop will be sprayed out with herbicide to stop transmission to other plants.

Phytoplasma infected regrowth in Warra mungbean stubble. Photo by Matt Skerman, Landmark, Dalby.

Article by Hugh Brier and Liz Williams