New rust on daisies spreads rapidly

Shropshire Botanical Society Newsletter - Autumn 1999 - page 4

Tom Preece

During 1997 and 1998 a distorting and yellowing rust disease was seen on daisies, Bellis perennis, in many places in England and Wales. Distinct from Puccinia obscura (which has an alternate stage on Wood-rushes, Luzula spp.) and from P. lagenophorae (which it closely resembles), this is an Australian rust, Puccinia distincta. I have seen it on cultivated daisies in flower pots at Shrewsbury bus station and railway station for several years (at least since 1989), as well as in Cae Glas park, Oswestry. It had not been found on wild daisies in Shropshire until I found it on a lawn at Highley in the autumn of 1997. Since then it has been found all over the county, as in the rest of Britain.

The story of its biology is told in two recent papers from Exeter University, listed below. In a third paper, I have discussed the probable origin of this "new" rust and plotted its spread as seen from herbarium and fresh specimens. I have been puzzled by the rust on large cultivated "pom-pom" daisies for more than 25 years. The team at Exeter, associated with John Webster, have solved this puzzle in a very clear way for us all. Evaporating the three papers to their essentials, it is clear now that this "new" rust, P. distincta, was introduced to Britain in the 1970s on cultivated large daisies; it has now spread to wild daisies. This spread was particularly dramatic in 1997 and 1998, on both cultivated large daisies and the ordinary wild daisy. This year, 1999, severe rust damage to wild daisies in grass verges and lawns is occurring and the rust has been exceptionally severe on cultivated Bellis in towns and gardens. Time will tell, but the impact of this rust on one of our commonest wild flowers is at present difficult to assess. The history of imported disease-causing fungi is not a happy one…

References

Weber, R.W.S. et al. 1998. Puccinia distincta, cause of a devastating disease of daisies. Mycologist 12:87-90.

Weber, R.W.S. et al. 1998. Puccinia distincta, cause of the current daisy rust epidemic in Britain, in comparison with other rusts on daisies, P. obscura and P. lagenophorae. Mycological Research 102:1227-1232.

Preece, T.F. et al. (in press). Origin and spread of the daisy rust epidemic in Britain caused by Puccinia distincta. Mycological Research (accepted July 1999).

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