White rust found on chrysanthemums in cut flower production


<div>At the end of August and beginning of September a plant disease by the name of white rust (Puccinia horiana) was found in three cut flower production units growing chrysanthemums. This is a quarantine organism as mentioned in the Phytosanitary Act which will spread quickly through chrysanthemum cultivations under favourable conditions.</div>

The first case of white rust was tracked down with the help of the report from a grower. The disease has a tendency to occur in epidemics. Evira is clarifying the origin of the disease and will when necessary organise tracing inspections for plant retailers where potentially contaminated plant material has been delivered. The disease is significant only when it occurs in commercial chrysanthemum production, where it produces financial losses by ruining the look of plants intended for sale.

The last time white rust was found on chrysanthemums in Finland was in 2001, when it was found in ten plant retail outlets. At the initial stage the disease causes small light spots on the leaves of the chrysanthemums, and as the disease progresses the large spore clusters forming on the underneath of the leaves drastically ruin the look of the plants.

Growers of chrysanthemums should now check the plants for white rust. When symptoms indicating white rust appear on the plants, Evira’s Plant Health Unit or the plant health inspector of the TE-Centre should be contacted without delay. When the disease is found at an early stage, preventative measures can stop the spread of the disease in some cases.

For additional information, please contact:
Senior Inspector Jari Poutanen, Evira, tel. +358 20 77 25126
Senior Officer Paula Lilja, Evira, tel. +358 20 77 25043

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