A neighbor is cactus-sitting 2 very large cuttings of Austrocylindropuntia subulata. He tells me that on one with 2 large arms, the arms 'suddenly' drooped as if wilted. The plant is not wrinkled nor is the soil wet. There are small dark spots scattered about the flower buds and evidence of some type of tissue damage, from our local beetles I think, that is old and dry. I have a baby A. subulata and it's arms are just naturally rather droopy it seems to me.
Any and all ideas are welcome. I can't do anything about his cactus but my own collection of around 200 species is right next door. I'm already fighting cochineal bugs from infested cuttings this guy brought home. BTW - I live in southern Arizona so all my plants are growing outside.
Disease?
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cactophile
- Posts: 3
- Joined: Fri May 27, 2005 1:25 am
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templegatejohn
- Posts: 1198
- Joined: Wed Sep 01, 2004 2:57 pm
- Location: Leeds, England
Diseased cacti
Hi there,
The first things obviously is to keep the plant as far away from any others as you can get it.
If the plant is not your it is difficult to recommend anything drastic. But if the plant is drooping the first thing I would do is have a look at the roots.
The plants may have root meal bug (cochineal insect), or some other pest. Vine Weevil is notorious for causing this sort of problem and can be difficult to erradicate although in the Uk there is now a new treatment out, although it is quite expensive.
Without seeing the dark spots, they could be anything. Sun spots from water on the plant body, Frost marks (unlikely I suppose in California), or Fungus rot, which probably means the plant is kaput, unless clean cuttings can be taken.
A good spray with a systemic insecticide will not do any harm and may be of great help. It should certainly kill any mealy bugs or red spider mite, but if it is Vine Weevil something more drastic may be needed.
Hope I haven't been too pessimistic.
John
The first things obviously is to keep the plant as far away from any others as you can get it.
If the plant is not your it is difficult to recommend anything drastic. But if the plant is drooping the first thing I would do is have a look at the roots.
The plants may have root meal bug (cochineal insect), or some other pest. Vine Weevil is notorious for causing this sort of problem and can be difficult to erradicate although in the Uk there is now a new treatment out, although it is quite expensive.
Without seeing the dark spots, they could be anything. Sun spots from water on the plant body, Frost marks (unlikely I suppose in California), or Fungus rot, which probably means the plant is kaput, unless clean cuttings can be taken.
A good spray with a systemic insecticide will not do any harm and may be of great help. It should certainly kill any mealy bugs or red spider mite, but if it is Vine Weevil something more drastic may be needed.
Hope I haven't been too pessimistic.
John
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cactophile
- Posts: 3
- Joined: Fri May 27, 2005 1:25 am
Thanks templegatejohn, you're not pessimistic. Had it been my own plant I would have taken a look at the roots first thing. I don't know if it has much of a root system, it could be a relatively newly potted cutting. If it had been my cutting it wouldn't have been potted anyway. A. subulata does quite well outside here.
BTW; I'm in southern Arizona, not California, our elevation here is about 2900'. We do get some quite cold nights in winter, into the teens farenheit, but heat and intense sun are much more stressing to plants. We've just had a week in the low 100's. I got my neighbor to further isolate this plant by suggesting he move it somewhere where it would not get the afternoon heat and sun.
BTW; I'm in southern Arizona, not California, our elevation here is about 2900'. We do get some quite cold nights in winter, into the teens farenheit, but heat and intense sun are much more stressing to plants. We've just had a week in the low 100's. I got my neighbor to further isolate this plant by suggesting he move it somewhere where it would not get the afternoon heat and sun.