Agave - possible parasite / slug attack or something else?

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guyhamilton
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Agave - possible parasite / slug attack or something else?

Post by guyhamilton »

Hi,

I have an Agave that is fairly large in a pot in littlehampton in the UK. Its mild and we rarely get much frost. He has very recently started to suffer from what I thought might be slug attack;

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I have been using copper tape around the pots which has worked till now. But left for a couple of days and I think the copper tape must of deteriorated and I came back to find the damaged show in the attached photos. Last night when I returned I replaced all the copper tape and as a further measure sprinkled slug pellets around the base. I had some further damage in the morning - I have two small Agaves next to it which have remained untouched.

The more I have looked at it the more I think it probably isn't slug attack as its as if the insides of the plants leaves have drained out - you can see a sticky sap has dripped down and hardened. I can't see any bite marks or stripping of the leaves surface.

Any thoughts on what it might be? I water the plant (not too much) every 10 or so days with rainwater mixed with miracle grow liquid feed. It sits in full sun in the middle of the garden

Thanks

Guy
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Re: Agave - possible parasite / slug attack or something else?

Post by esp »

The last photo looks a lot to me like stripping of the surface - it greatly resembles some slug damage I got recently on an opuntia - just the epidermis seemed to have been eaten, in a thin layer.

As for the sap - is it exuded anyway from shallow surface wounds? Having suffered the damage you have already, it would seem easy enough to test a further small area and see what happens.

Slugs often - but not always - leave characteristic slimy trails. Were these present anywhere on the plant?
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Re: Agave - possible parasite / slug attack or something else?

Post by agavedave »

Looks like scorch marks, is it all over the plant or just the side that got direct sun on a v.hot day?

Initial damage probably happened over a week ago.

best Regards
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Astro
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Re: Agave - possible parasite / slug attack or something else?

Post by Astro »

I've had very similar looking damage on some of my agaves - the soft epidermis is stripped, leaving the tissue underneath to dry out and burn in the sun. In my case it was due to snails not slugs, but I guess that's an instance of 'six of one, half a dozen of the other'. They like to hide under the leaves or underneath the pot.

A saucer with some beer left out overnight will lure them out and take care of them.
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Re: Agave - possible parasite / slug attack or something else?

Post by Mandy »

I had this happen to me in winter when they where in the green house and I found that mice where living in it . I sware it was them stripping the leafs . But I maybe wrong.
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Re: Agave - possible parasite / slug attack or something else?

Post by Liz M »

In a pot in the very dry weather we have had recently, I would think your Agaves could have simply dried out. In hot weather they would still want to use as much water as ever and would have run out with no rain. In most circumstances I would water Agaves more than once every ten days in the growing season and certainly absolutely soak it every time, then water when dry.
Obsessive Crassulaceae lover, especially Aeoniums but also grow, Aloes, Agaves, Haworthias and a select number of Cacti.
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Re: Agave - possible parasite / slug attack or something else?

Post by BrianMc »

Snails can rasp the surface off Agaves as has been mentioned, but I am inclined to go with Agavedave and say scorching.

One thing that struck me was that that pot looks pretty small for an Agave of that size. I would guess that the soil ball is completely roots. I realise that in a bigger pot the plant might become unmanageable, but if the plant is potbound it may be reaching a point where it will become stunted and begin to decline. You may find that it begins to lose leaves at the same rate that new ones are produced.
A potbound agave will use up all its water very quickly this time of year, so during the recent heat wave, the roots may well have been cooked in such a cramped pot, which can only assist the scorching of the leaves. In hot sunny weather, I think you may need to water every other day. It certainly wouldn't do your plant any harm.
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guyhamilton
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Re: Agave - possible parasite / slug attack or something else?

Post by guyhamilton »

Thank you everyone for your responses - its good to have a wealth of experience to draw upon in times of need.

I think scorching sounds like the reason, its happened during the hottest part of the year so far when UV levels were particularly high and we hadn't had rain for quite a while. He is also in the centre of the garden where there is little shade. I did look for snails during the night and couldn't find any.

I think I have been a bit mean on the water (perhaps a litre every ten days) as I thought it would be better to water less than over water him. I will be more generous with the watering in future and make it more frequent in hot weather.

The plant was previously owned by my late mother who lived further inland (Guildford) and so he had to be kept in a pot. Now that I live by the coast where frosts are very rare, I am planning to plant the agave in the ground (well drained raised bed) possibly this year or next as he is now too big to keep in a pot. A neighbour has in fact planted two in front of his house and they have been growing happily for 15 years or so including the more tender variegated variety.

If and when I do plant him in the ground - I assume a well drained sandy soil mix would be appropriate on a bed of bricks or similar?

Thanks again everyone

Guy
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Re: Agave - possible parasite / slug attack or something else?

Post by LexyBoy »

Has it been moved or covered at all? I have seen the same thing a couple of times when Agaves have been moved from shade to sun or vice versa. It's dubbed 'Agave oedema' in the states - though there seems to be some controversy over its veracity - and has been put down to the mishmash of photosynthetic pathways the genus uses, which may cause cells to burst under some conditions. For example, with moist soil photosynthesis will take the C3/4 pathway with stomata open in the day; suddenly moving into shade will cause the stomata to close before gas exchange is complete (so goes the hypothesis). Whenever my Agaves have been 'sunburned' the damage is not only in the most exposed parts of the plant, and the damage looks different to other sunburn damage I've seen so I think a similar reasoning may apply.

Interesting article here: http://www.thedangergarden.com/2016/09/ ... edema.html

(And Hello BTW).
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