Rust fungi. Paul Smith. All photos copyright of Paul Smith

Transcription

1 Rust fungi Paul Smith All photos copyright of Paul Smith

2 Outline What are rust fungi? Life cycles of rust fungi Oddities galls and parasites Finding and recording rust fungi A few common rusts to look out for

3 What are rust fungi? Plant parasitic fungi with very specialised lifestyles Two big groups of fungi Ascomycetes many moulds, plant parasites and decay fungi Basidiomycetes mushrooms and toadstools, rusts and smuts Rusts are very unusual basidios

4 What are rusts? The name comes from the colour of the spores Spores are generally all that is visible There is some mycelium (fungal tissue) in the host, to gather nutrients Most rusts can t be grown away from their hosts, even under specialised conditions

5 Puccinia glomerata on ragwort

6 Puccinia coronata on Yorkshire fog

7 Rust life cycles Initial infection is from a basidiospore, from which fungus grows inside host This first infection produces spermogonia with 0 s (spermatia) often barely visible Two infections combine, and combination gives rise to new pustules containing I s (aecia) Like clusters of balls when developing Rupture to show spores, looking like volcanoes Usually early in the year

8 Uromyces dactylidis I on Celandine

9 Puccinia urticata I on Nettle

10 Life cycles (cont) I s generally infect the alternate host, a different species The new infection on the new host gives rise to new pustules containing II s (uredinia) Rustiest stage? Rust-coloured, powdery Spores usually spiky or warty II s can infect new plants of the same species to make more II s Some species persist as II s

11 Puccinia calcitrapae II on Hardheads

12 Puccinia hydrocotyles II on marsh pennywort

13 Life cycles (cont) Same infection leads to IIIs, the perfect state IIIs are resting stage overwinter, typically found late in year Spores usually smooth Can be 1, 2 or many-celled (taxonomy) When conditions right, IIIs germinate to form tiny fungus with basidia, makes IV s (basidiospores) Short-lived Infect new hosts

14 Puccinia obscura III on Woodrush

15 Puccinia cnici III on Spear Thistle

16 Uromyces rumicis III on Sheep s Sorrel

17 Phragmidium violaceum III on Bramble

18 Variants of life cycles Some rusts do all stages on one host Puccinia punctiformis on Creeping Thistle A few species have only some stages Trachyspora intrusa I, III on Lady s-mantles Several species have only one spore stage Uromyces muscari III on Bluebell Puccinia epilobii III on Willowherbs Chrysomyxa empetri II on Crowberry (IIIs known, but not in Britain)

19 Trachyspora intrusa I on Lady s-mantle

20 Oddities galls and parasites A number of rusts cause reactions in their hosts leading to galls some quite pronounced Puccinia urticata I on Nettle Puccinia circaeae III on Enchanter s Nightshade Several other fungi parasitise rusts hyperparasites Eudarluca caricis has cleistothecia in pustules Tuberculina persicina on surface

21 Puccinia urticata I on Nettle

22 Triphragmium ulmariae I on Meadowsweet

23 Eudarluca caricis

24 Tuberculina persicina Image removed for copyright reasons available at 63C506B1?page=ViewImageData&service=external&sp=10921&state:ImageGallery=ZH4 siaaaaaaaaafvzlog1njebgygjgyetlz8l1toluiiblyuxlfevjzevxc8npy%2fduvvjhdp9yvez GBi9GFjLEnNKUyuKGAQQivxKc5NSi9rWTJXlnvKgG2hURQEDGJwwKhdgYODNTU3JTHTOSSwu9swr AZoviNAKFEhNTy0SerRgyffGdgugFZ4wKwoZ6hgYQaYAAClYw76lAAAA

25 Finding and recording rusts Finding Learn which plants have rusts (and when!) Unexpected species do ferns, conifers Look for yellowed or manky leaves, look at undersides start in your garden! search pattern develops with experience Be prepared to spend time searching!

26 Puccinia graminis on Mahonia

27 Gymnosporangium cornutum on Juniper

28 Recording ID Most plants hosts have only 1 rust; at most a few Ellis & Ellis Microfungi on land plants Henderson Guide Henderson2004-BritishRustFungiHostPlantGuide.pdf Generally need to check spores under microscope Recording Just like other groups, but also handy to have info on hosts, spore stages and parasites if any FRDBI

29 Coleosporium tussilaginis I on Black Pine

30 Coleosporium tussilaginis I on Black Pine

31 A few spring rusts to look for Uromyces muscari III on Bluebell Dark brown spores, a group of sori forming a patch on a leaf Puccinia punctiformis 0, I on Creeping Thistle Infected shoots spindly and covered with spores Smells of honey Puccinia lagenophorae I on Groundsel, Ragwort etc

32 Puccinia punctiformis on Creeping Thistle

33 Thank you! Puccinia chaerophylli on Sweet Cicely