Crinum failure

[Arnold]

I had a number of Crinums seeds that germinated and grew  for two years in a pot.  Planted out last year and grew well.

The year in spring the bulb showed no signs of growth.  I dug it up and cut off the top dead leaf remnants and the attached photos show what I found.  My guess is a Narcissus bulb fly larva is somewhere deep in side the bulb.  The bulb is firm and has a good root system attached.

Any suggestions would be appreciated.

[CG100]

Most Crinum in active growth like plenty of water, even ones from arid areas.

The only time that I have seen what I assumed were Narcsissus fly grubs, they were "huge" - a quick Google and that seems to be correct.

All the ones here are grown in pots, even macowanii, which is hardy through much of the UK. I did find root rot in one bulbispermum this spring, which took the root plate, so anything regenerated from that will be a miracle

[Arnold]

The bulb is very firm.  Other than the small area that's dark in the middle of the bulb no other issues.  All my other Crinums outdoors have sprouted and growing well.

[CG100]

Looking again at your photo's, it might be similar to the one lost here.

Obviously, where the rot started is impossible to say, but the roots, root-plate and the very centre of the bulb rotted. I bought the plant as a smalls eedling and it has been on my kitchen windowsill for 5 years at least, left totally dry all winter. It was one of 4 Crinums, sperate pots, all the others are OK (so far).

My understanding is that heart rot in plants is generally bacterial.

Depending on what the problem is, you could propagate it.

[Uli]

Hello Arnold,

To me it looks more like a central bacterial rot and not narcissus fly. I have a lot of damage due to Narcissus fly but so far Crinum was never attacked. But I have had central rot. For Narcissus fly you could try to carefully poke into the black area with a thin piece of wire or an open paper clip. Sometimes you can pull out the larva this way. 
I would plant the damaged bulb back into a pot with the cut off surface exposed for better control and hope that it will produce offsets.

[Arnold]

Hi Uli

That's exactly what I did.  I've had bulbs infested with the NBF and the bulb was mushy and debris was pushing out of the entry point for the larva, not so in this case.
 

Thanks,

[Arnold]

As an update on the Crinum.  I dug it up and potted in in the greenhouse. Dusted the cut surface with some sulfur powder.  It has showed some small green shoots.  I wonder if it just a late grower?

[Martin Bohnet]

Hmm. looks like it has now 2 growing points - this DOES speak in favor of a damaged basal plate. 

[Arnold]

Hi Martin

I agree.  Not sure how that occurred.  There's more than two.   On one side of the bulb there's a shoot appearing near the base of the bulb