diseases and pests

Friends,
When digging bulbs recently, I came upon several bulbs that look like the attached photo.  The central basal plate looks sort of like a cork that has been partially put back into the bottle. Does anyone know what causes this, or if it has a name?   The bulbs were discarded, so no chance to send it for any testing.
Mary Lou

 

6 comments for “diseases and pests

  1. I wonder whether it is as a result of restricted growth. I don’t know whether you have had a very dry growing season, but I have seem similar distorted bulbs when pots in the greenhouse have been hidden under the staging and consequently did not get watered over a very long period.

    James

  2. Mary Lou,

    I have seen this before; however, the only thing that comes to mind is that in basal rot you will sometimes see separation of the basal plate from the bulb scales; however, in the basal rot case, the fungus is usually obseved around the edge of the basal plate.

    Ted

  3. Thanks for your reply, James. I wouldn’t have said we had a very dry growing season, but it was very dry for the weeks before I was digging.
    Mary Lou
  4. Without seeing the bulb close up, it looks like you might have had an attack of Keel Slugs which are subterranean, they are black in colour and their back is shaped like a ships keel hence the name.

    The main symptoms are that the base plate partially separates from the bulb skin layers, this is where the slug has chewed the outer layer of the bulb and its base plate.when you lift the bulb will be very firm but due to the damage to the inner layers of the bulb if you were to replant, the moister of the soil would penetrate the inner layers causing the bulb to rot. If you were to lift it in the spring because the bulb had not appeared through the surface of the soil it would display all the symptoms of basal rot.

    As this slug is subterranean conventional slug bait will not kill it you need a liquid form of killer of a parasite to get rig of it. I used to sterilize my plot with Methyl Bromide until it was banded which kept the little pest at bay and we have no liquid killer anymore, so I am using the parasite.

    I hope this helps but to make a sure diagnoses from a photo is very hard, I would recommend that you contact your local ministry for horticulture they should be able to tell you what has caused is and how to cure the problem.

    Roger

  5. Hi Roger,

    Many thanks for your reply. It was something I’d never seen before. I’m cutting back on the size of my garden, so won’t be planting daffodils in that location again. But I will be treating a different bed with Basamid, which is the alternative in the U.S. to Methyl Bromide. Still a nasty killer to use, so I’ll have to be very careful. To buy it requires a “Permit to use restricted pesticides” which I got some years ago when I had an infestation of nematodes. My permit has long-since expired, but I still have some Basamid on hand, and hope it is still effective. Between the Basamid and covering the plot with plastic over the summer for solarization, I hope to kill any basal rot spores in the soil in that area.

    Best wishes,

    Mary Lou

  6. Hi Mary Lou,

    I did not get around to replying earlier but I have to somewhat agree with Roger. I sometimes get bulbs where the basal plate has been chewed. I put it down to chewing by slugs,maybe, but in my case more likely centipedes or slaters as the slugs we have are less able to get to the base of the bulb. Probably more likely to be noticed here in dry conditions.

    Dave

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