I've always had pelargoniums on the balcony. Common as muck they may be, but in full bloom they're glorious. And with a bit of protection they will not only over-winter, and but also sometimes keep on flowering . If you were reading this blog a few years ago, you'll know that I had one container of salmon-pink zonal pelargoniums that went on for two and half years - in all that time, even in January when it was wrapped up in fleece, there wasn't a moment when it wasn't in bloom.
But each year it got progressively more difficult to keep them alive through the summer. And last year I lost the lot.
So this year I replaced them all. Zonals, ivy-leafed, regals .... Here they are in May this year...
And I've lost the lot again.
Why? Again if you've been reading regularly for a few years, you'll guess. It's this ...
Cacyreus Marshalli, or the Geranium Bronze Butterfly. It's always been a problem, but for the last couple of years it's been impossible to keep the plants alive.
A quick recap for those of you who aren't familiar with it. Native to S.Africa (as are pelargoniums), it was introduced to S. Europe about twenty years ago and has been spreading like wildfire ever since. It's been in Italy since 1996, and is now posing a severe threat to commercial pelargonium cultivation - apart from anything else, because people are starting to avoid buying the plants, knowing they won't survive.
Why does it do so much damage? The larvae of the butterfly don't feed on the leaves. They burrow right into the stems and eat the plant from the inside out, killing it. If you can spot the tell-tale holes you can sometimes cut off the affected part - but over the season you frequently end up cutting back the whole plant.
And go away for a few weeks, like I always have to in the summer (...have to? Only a gardener could feel like that about a holiday ) and you come back to this ...
What can be done about them? There don't seem to be many organic options. One of the studies recommends the "natural" insecticide Bacillus thuringiensis Kurstaki - but don't ask me where I'd get hold of it. (Wonder how many times longer than the bacteria the name is?) There is also an insect with the equally wonderful name of Macrolophus caliginosus Wagner, which feeds off the eggs and hatchling larvae - but ditto, and would it stay on the balcony anyway? Another source suggested companion planting. Highly aromatic plants like lavender, mint and thyme are supposed to discourage the butterfly. Well, I can try - but I have my doubts. By pure chance I did have mint growing fairly near the pelargoniums this year. Not close enough maybe ...
Other than that, it seems there are only two choices - swamp the plants with noxious chemicals, or give up on pelargoniums all together. Don't like the first, and don't want to do the second. But it seems the only other option is to invite yet another massacre ...
Useful Links
Lupi and Zucker, The butterfly cacyreus marshalli in Northern Italy and susceptibility of commercial cultivars of pelargonium.
Regione del Veneto, Il licenide dei gerani
14 comments:
Great post ... and your comment did get through .... eventually and I've posted it to prove it! Don't think I ever congratulated you on your Blotanical award success, but here goes .... and well done belatedly!
What a shame, as those geraniums were beautiful!
I don't know about swamping the plants with toxic chemicals, but it seems like this might be an instance where a good systemic insecticide could do a world of good.
Alternately, perhaps netting? The butterflies look pretty tiny, so it might have to be a pretty fine mesh, and you'd prevent pollinator access to any other plants that were potted in the same container, but . . . maybe?
So sorry to see your geraniums in such a miserable condition, netting might be a good option to control butterflies :)
A horribly fascinating post, but so sad for you. Are you or anyone you know going to the States any time soon? You can buy the insecticide there, marketed as Thuricide BTK.
If that butterfly makes it up across the Alps to northern Europe it will cause havoc! Where I live in Germany there's hardly a balcony anywhere without pelargonia, and it's hard to imagine places like Alsace without the glorious geraniums (as everyone calls them) at the windows of the half-timber houses. I hope you find a remedy.
Thanks for your comment on my blog - it's been great hearing from gardeners all over the world through Blotanical.
Oh that was a very sorry sight indeed. I feel for you. I love my holidays but always feel i'm missing something and i feel a bit gulity.
sorry to note this, I guess it would be better to try plant other hardy plants than going thru this heart-ache over & over again.
Sue you have taught me the name of our little butterfly. Yes he burrows into the stems and I cut them back. But I guess we have enough happy birds feeding their nestlings, and the pelargoniums are so vigorous that I have to keep cutting chunks and swags back - so there is enough for both of us at home in South Africa. I am wondering if the fancy modern hybrids are not as tough as the original species?
Sorry to see the plant.
Congratulations on your award..
How frustrating!! Hope you have the heart to get more pelargoniums. They are beautiful.
Aah! Horrible feeling when you lose plants....
I believe BT is okayed for organic farms, so apparently it is not too evil.
In fact one of the complaints about genetically modified crops is Monsanto and its ilk are incorporating BT into their modified plants, so the fear is that soon bugs will become resistant, kind of like if every human popped an antibiotic in the morning, rendering BT useless for organic farming.
By the way, the host to complain to about that site stealing your content which Kathy noted below is
copyright@theplanet.com
I think you are on a loser :-) Have you tried the scented leaved ones - Fragrans, Tomentosum etc. Can't imagine they would be any different but it might be worth a go.
Hope the butterfly does not reach the UK - that's one invader I can do without.
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