Antxiara
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Joined: Wed Apr 17, 2013 6:39 am
Location: Ubeda, Spain

Geranium Stems Are Black Inside!

Hello Everyone!

I have have been gone a month from my home and someone has been watering my plants. When I got home I thought since it had been very hot and dry that my geraniums had dried up...but there was still some green parts so I just started trimming the dry parts. However I see that there are like black holes and the inside of the stems are black...looks like fine wet soil. I can't see any pests. I looked online and well it doesn't look like stem rot but I'm not sure. Anyone know what it is and if it can spread to other plants?

Thanks in advance!!
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Holes on the stem
Holes on the stem
Inside of the stem
Inside of the stem

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applestar
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Posts: 30514
Joined: Thu May 01, 2008 7:21 pm
Location: Zone 6, NJ (3/M)4/E ~ 10/M(11/B)

The holes with blackened "sawdust" inside suggested stem borer of some kind so I searched and came across this. Have you seen moths like this flying around?
https://en.wikipedia.org/wiki/Plume_moth
Geranium Plume Moth (Amblyptilla pica)

...I have to admit I have! I never ID'd them before, but now I know what they are, and what mischief they have been up to. :x

Antxiara
Newly Registered
Posts: 7
Joined: Wed Apr 17, 2013 6:39 am
Location: Ubeda, Spain

I haven't seen any moths or insects...that's why I'm so lost on what it could be. Maybe there were moths and they have left?

imafan26
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Posts: 13962
Joined: Tue Jan 01, 2013 8:32 am
Location: Hawaii, zone 12a 587 ft elev.

I get that too. They are borers and usually you will see a small hole on the stem. I never see the moth because they usually come out late in the evening. Over watering can also cause rot. Geraniums should only get watered when the soil is nearly dry.



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