New rust (for GB) on Himalayan Balsam

[Sheffield Lass]

Just discovered where you are all hiding out these days. Great to see a new forum to replace the defunct one!

Just to let you know that CABI (after lots of testing) are currently releasing a rust specific to Himalayan Balsam in the UK as part of biological control of the balsam – Puccinia komarovii var. glanduliferae So one to keep an eye out for. Not sure where you need to send sightings to – possibly CABI

More details:

http://himalayanbalsam.cabi.org/scientific-research/” class=”bbcode_url”>http://himalayanbalsam.cabi.org/scientific-research/

There are a number of release sites around Britain, including North Yorkshire near Whitby 2 sites. Infected plants were planted out there last week. In total 25 sites this year – Berkshire (2 sites), Middlesex (1site), Kent (1 site), Gloucester (1 site), Cornwall (6 sites), West Yorkshire (4 sites), North Yorkshire (2 sites), Northumberland (4 sites), Swansea (2 sites) and Ceredigion (2 sites).

The rust looks like your typical rust, but has all its life cycle stages on Himalayan Balsam. It infects the stems and leaves.

March-May: The first visible signs on stems of small Himalayan balsam seedlings. Small yellow /orange cups, erupt causing the stem to elongate, bend and become distorted. The area of infection may also become red. Stems of infected plants are usually longer than seedlings that are not infected.

May – September: Small yellow spots or whitening on the upper leaf surface develops. About a week later, on the lower leaf surface, but associated with these yellow spots, small light brown pustules (uredinia) form.

August – September: the light brown pustules on the lower leafsurface, become darker in colour and form dark brown/black pustules (telia). This stage representsthe over-wintering stage. Infected leaves will naturally fall to the ground where they will remain over winter to infect stems again the next spring.

[Chris Yeates]

Hi Melanie

whoops – I though I’d emailed you about this site – we must have missed you off (not by design I assure you 😳 ). This will be interesting to watch; one trusts that it is very specific to I. glandulifera and won’t attack other members of the genus – particularly the native I. noli-tangere. Certainly Puccinia argentata doesn’t infect HB: http://www.fieldmycology.net/FRDBI/FRDBIrecord.asp?intGBNum=1091” class=”bbcode_url”>http://www.fieldmycology.net/FRDBI/FRDBIrecord.asp?intGBNum=1091. Of course it is not in the interests of the fungus to eradicate its host . . . .

If very successful this programme may have an effect on bumble-bee species, particularly in late summer where in this region at least HB seems to be the favoured (and most abundant) pollen source . . . .

Chris

[marksteer]

I picked up on CABI’s work last year. Very interesting to me as we have major problems with HB in South Wales and I am often out pulling it in Brynna Woods NR and elsewhere. It would be interesting to hear Nigel’s opinion on this ( brief discussion with him recently he didn’t think good idea!)

Mark

[adampembs]

It looks like they have done their research well and it is well tested on similar species. Non-native invasive species (NNIS) may be used by other things, eg bumble bees, but the all the species they exclude when they run rampant have a greater number of associated invertebrates & fungi which disappear from the loss of that space. I suppose one issue is that the use of a rust accepts the continued presence of Himalyan Balsam and rather than trying to eradicate it, it merely reduces one of its competitive advantages over native species. Biological eradication would need something more aggressive and risky (like one of the Phytophthoras.) I’d be interested to know why Nigel disagrees with this.

One of the worst NNIS in my area is Petasites fragrans (Winter Heliotrope) – it flowers in the winter and appears to aggressively colonise areas favoured by Ramsons. Unlike Ramsons, it”s foliage lasts all year and excludes pretty much everything else. Apparently it is quite susceptible to frost (it originates from North Aprica) and perhaps that is why it does well in Pembrokeshire, as we have mild winters thanks to the gulf stream. I see Chris Yeates has found Coleosporium tussilaginis on P.fragrans, even though it isn’t listed as a host in Henderson’s rusts by host plant (2004)

[marksteer]

According to CABI this Rust does not affect I.noli-tangere – see FAQ answers on their website. However I am concerned about the release of a non-native species – there are quite a few instances of unforeseen problems.

[adampembs]

marksteer wrote:

According to CABI this Rust does not affect I.noli-tangere – see FAQ answers on their website. However I am concerned about the release of a non-native species – there are quite a few instances of unforeseen problems.

It goes much further than that.

Quote:

“We have tested the safety of this Himalayan balsam rust following strict internationally recognised testing procedures. We compiled a test plant list comprising 84 entries; this consists of 74 species and an additional 10 varieties of three widely grown ornamental species in the UK. There are 26 UK-native plant species, 52 ornamental plants, three economically important crop/ fruit species and three introduced/ invasive species on the list.

Through our research under quarantine conditions we clarified the lifecycle of the rust, thus proving that all spore stages observed on Himalayan balsam in the native range belong to the same species. We have backed up this research with molecular evidence.”

This seems pretty watertight.

Is the same thorough safety testing being carried out on plants introduced into the UK? Certainly within the EU, it’s an open house.

https://www.rhs.org.uk/advice/profile?pid=435” class=”bbcode_url”>https://www.rhs.org.uk/advice/profile?pid=435

Quote:

Within the European Union (EU) there are no border checks for plants and plant products travelling between member states and, it is possible, to import and export plants freely with very few exceptions.

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