I have these blemishes on some Rebutias and a Tephrocactus. They're raised, hard and don't scratch off easily. Could anybody suggest a cause and whether they might be contagious. Any suggestions for treatment would be appreciated but they look permanent to me. They don't appear to be scale and I don't think they're sun scorch,so possibly mite damage but I really don't know.
Thanks for any suggestions.
Cactus blemishes
Forum rules
For the discussion of topics related to the conservation, cultivation, propagation, exhibition & science of cacti & other succulents only.
Please respect all forum members opinions and if you can't make a civil reply, don't reply!
For the discussion of topics related to the conservation, cultivation, propagation, exhibition & science of cacti & other succulents only.
Please respect all forum members opinions and if you can't make a civil reply, don't reply!
-
- BCSS Member
- Posts: 555
- https://www.behance.net/kuchnie-warszawa
- Joined: 18 Mar 2013
- Branch: SHEFFIELD
- Country: UK
- Role within the BCSS: Member
- Location: Peak District, United Kingdom
Cactus blemishes
Cheers
Gary
Plant Interests
cacti & other succulents, carnivorous plants
Gary
Plant Interests
cacti & other succulents, carnivorous plants
Re: Cactus blemishes
Looks like scale to me, particularly on the Rebutia. Isolate and treat with SB Plant Invigorator weekly for a few weeks.
Stuart
Stuart
- Ali Baba
- BCSS Member
- Posts: 2298
- Joined: 26 Dec 2007
- Branch: DOVER
- Country: UK
- Role within the BCSS: Member
Re: Cactus blemishes
Not scale, you don’t get marks with scale, just scales! Looks like thrips damage to me, typically occurs in the winter on Rebutia around the growing point and the damage appears and expands as the plant grows, by which time the thrips have grown up and flown away
- Flayzerflay
- Registered Guest
- Posts: 114
- Joined: 21 Feb 2020
- Branch: None
- Country: UK
- Role within the BCSS: Member
Re: Cactus blemishes
If the raised bumps have a darker dot in the middle it's scale, you may just have several generations expanding their empire.
Systemic is required so they get poisoned.
Systemic is required so they get poisoned.
-
- BCSS Member
- Posts: 555
- Joined: 18 Mar 2013
- Branch: SHEFFIELD
- Country: UK
- Role within the BCSS: Member
- Location: Peak District, United Kingdom
Re: Cactus blemishes
Thank you for the replies. I had discounted scale because I've had examples of them before, so I knew what they look like, but I'll definitely have another look and try SB Invigorator anyway as I have some somewhere. Ali's thrips theory sounds interesting although I have rarely seen any in my greenhouse. If it was them then they seem to have moved on as I couldn't spot any under a magnifying glass.
What with mealies, root mealies, RSM and now possibly thrips to be constantly on the lookout for it does take the shine off the hobby after a while.
Thank you all.
What with mealies, root mealies, RSM and now possibly thrips to be constantly on the lookout for it does take the shine off the hobby after a while.
Thank you all.
Cheers
Gary
Plant Interests
cacti & other succulents, carnivorous plants
Gary
Plant Interests
cacti & other succulents, carnivorous plants
- Flayzerflay
- Registered Guest
- Posts: 114
- Joined: 21 Feb 2020
- Branch: None
- Country: UK
- Role within the BCSS: Member
Re: Cactus blemishes
Makes you wonder how the Thai growers never get these issues, i suspect it's the systemics used are furan based and hence banned.
-
- BCSS Member
- Posts: 2321
- Joined: 13 Feb 2009
- Branch: SOUTH WALES
- Country: UK
Re: Cactus blemishes
I have read that scale has thousands of species,affecting plants. Some are flat, others raise tiny brown lumps. Take your pick lol.
-
- BCSS Member
- Posts: 555
- Joined: 18 Mar 2013
- Branch: SHEFFIELD
- Country: UK
- Role within the BCSS: Member
- Location: Peak District, United Kingdom
Re: Cactus blemishes
On another Rebutia the bumps did indeed look as though they might have a darker dot in the middle. So maybe there are several generations or just a tiny lumpy species as Eric suggested.Flayzerflay wrote: ↑Sat Jun 27, 2020 11:13 am If the raised bumps have a darker dot in the middle it's scale, you may just have several generations expanding their empire. Systemic is required so they get poisoned.
I've sprayed with SB Invigorator and will repeat for a few weeks to see how it goes.
Cheers
Gary
Plant Interests
cacti & other succulents, carnivorous plants
Gary
Plant Interests
cacti & other succulents, carnivorous plants
- iann
- BCSS Member
- Posts: 14574
- Joined: 11 Jan 2007
- Branch: MACCLESFIELD & EAST CHESHIRE
- Country: UK
- Role within the BCSS: Member
Re: Cactus blemishes
My first thought was oedema. Scale can be scraped off fairly easily. It may leave a mark but not cause a lot of damage. Trying to scrape off oedema or scars from any other reason will not be easy and will cause significant damage.
Cheshire, UK
-
- BCSS Member
- Posts: 555
- Joined: 18 Mar 2013
- Branch: SHEFFIELD
- Country: UK
- Role within the BCSS: Member
- Location: Peak District, United Kingdom
Re: Cactus blemishes
Thanks Iann
I've tried scraping again and it's not budging, I feel I'd definitely have to damage the plants to remove any. Googling didn't really give me any images quite like mine but according to the search results the cause seems to be over watering although not enough to kill the plant completely. I'll continue with the SB Invigorator anyway for a few weeks and continue to monitor. Thanks again
Cheers
Gary
Plant Interests
cacti & other succulents, carnivorous plants
Gary
Plant Interests
cacti & other succulents, carnivorous plants