February 2017 – New Zealand BeeKeeper

11

NEW ZEALAND BEEKEEPER, FEBRUARY 2017

MYRTLE RUST: BEING PREPARED PEST AND DISEASE CONTROL

Karin Kos and Barry Foster

In December 2016, Karin Kos and Barry Foster from Apiculture New Zealand, along with Government, iwi and research organisations, attended a myrtle rust workshop in Wellington organised by the Biosecurity team of the Ministry for Primary Industries. Following is a summary of the workshop and next steps.

Figure 2. Yellow and purple pustules.

In Queensland alone, there has been a 66 percent dieback on affected trees, as well as loss of species that is likely to lead to extinction of some species, with cascading effects on invertebrates, birds and other links in the food chain dependent upon them. Although the impact of myrtle rust on the bee population has not been researched in Australia, there is an impact on pollination interruption. Bob Makinson, a conservation biologist from New South Wales, highlighted some of the issues Australia faced including lack of a coordinated approach, with each State doing its own thing, and not being prepared early enough. The key lessons shared by the Australians included this lack of a coordinated response, the need for a botanically literate workforce for surveillance, and more studies on all impacts, including the economic and environmental impacts of this fungal pest.

Myrtle rust (Puccinia psidii) is an invasive rust that infects plants belonging to the family Myrtaceae—including eucalypts, paperbarks, bottlebrush, tea tree and lilly pilly. It is native to South America and has spread to Central America, the Caribbean, Mexico, the USA (Florida, California and Hawaii), Japan, China, Australia and South Africa. The disease is spread rapidly through the movement of infected plant material, wind and water, insects and birds and human-assisted dispersal through transfer of clothing, other equipment and machinery. It starts off as small purple spots and transforms into yellow spores, having a devastating effect on the whole plant from its leaves, fruits and stem. While myrtle rust has not been detected in New Zealand, the aim of the workshop was to look at our preparedness and consider an action plan, as well as building on the science, filling the gaps in the research.

Learning from Australia’s experience Australian speakers at the workshop shared their experience of myrtle rust, which was first detected in Australia in April 2010 and has now spread along the east coast from Queensland to Tasmania. Geoff Pegg from the Department of Agriculture & Fisheries, Queensland, said that the lemon myrtle industry suffered an 80 percent loss of production, plus the loss of organic status with fungicide residues binding to oils from lemon myrtle.

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Figure 1. Images of myrtle rust infection on Australian plants. The disease starts as small purple spots and then produces yellow pustules on leaves. While not detected in New Zealand, if this type of spore is seen, do not remove the plant as the spores are very light. Take a photo and send the image to the Ministry for Primary Industries.

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