Antxiara
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Posts: 7
Joined: Wed Apr 17, 2013 10:39 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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Joined: Thu May 01, 2008 11:21 pm
Location: Zone 6, NJ (3/M)4/E ~ 10/M

Re: Geranium Stems Are Black Inside!

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
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Antxiara
Newly Registered
Posts: 7
Joined: Wed Apr 17, 2013 10:39 am
Location: Ubeda, Spain

Re: Geranium Stems Are Black Inside!

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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Joined: Tue Jan 01, 2013 1:32 pm
Location: hawaii, zone 12a 587 ft elev.

Re: Geranium Stems Are Black Inside!

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.
Happy gardening in Hawaii. Gardens are where people grow.

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