Archive
BLIGHT, RUST & SMUT
20/09/2019
The naming of these taxa of the fungal world derives from the hatred gardeners and growers understandably have for the diseases with which so many of them are associated. They are, though, part of life’s rich tapestry and play exceptionally important roles in the catabolic processes of decay and nutrient cycling in the natural world – some are of great medical and social benefit too (think how penicillin revolutionised health or how the noble rot, Botrytis cinerea Pers. (1794) (see below) makes such fine Tokay or Sauternes wines). This week I want to focus on a few of the common species of these taxa that you can observe easily at this time of year.
Its role in fine wines notwithstanding, Botrytis, also known as grey mould, is ubiquitous and you will find it easy to observe, if not always welcome. Look at these examples of it on an apple and a pear photographed just this month, as well as on a bunch of grapes:
Botrytis comes from the ancient Greek for grapes, βότρυς, with the Latin suffix -itis denoting disease. It is a fungus that causes rot (necrotrophic) and it infects a wide range of plant species as you will see if you look around.
Smuts and rusts, which produce fungal growths on leaves and other plant tissues, are also very common. They belong to a large group of fungi known as the Basidiomycota with an appearance that gives them their vernacular names. There are hundreds of species Britain. Below are one or two miscellaneous examples on leaves:
The central picture is a sooty mould and of interest because the organisms that promote it can be seen on the leaf (yellow arrows). These are scale insects (actually hemipteran bugs) which suck plant sap and exude a sweet “honeydew”, a nutrient on which the sooty mould fungus (this one is a Cladosporium species) thrives.
Incidentally, an interesting rust in the news currently is the one being used to combat the invasive exotic Indian balsam that has colonised so many of our river-banks, Puccinia komarovii var. glanduliferae. Information at: www.cabi.org/projects/project/32944.
Betts Ecology strive to maintain ecosystems that are naturally biodiverse and let nature be wild. We therefore don’t use toxic pesticides or fungicides but prefer to encourage the ecological dynamics of growth, resistance, decay, decomposer processes, energy flow and nutrient cycling that are so important to the overall health of our planet.
© Betts Ecology. All photos by Dr C Betts.
