Brown spots problem with Astrophytum cultivars...

[marazz53]

[marazz53]

[marazz53]

[marazz53]

[marazz53]

Hi ALL Astro growers, anyone knows the cure for this problem...THANKS... 99% of my plants are grown from seeds by myself...

[Arioandi]

It seems to be a big problem in your collection. At what temperature do you keep the Astros during wintertime?

[fanecchissimo]

i knew this problem. i had to throw away some plants,(i was crying)

after i destroyed all the infected plants i had no problem again.

i usually let the greenhouse to go below 0°C, this helps, in my opinion...

they talked to me really good about long lasting triazoles, because they don't let the fungus produce spore, and the replication is blocked...

[marazz53]

Hi Andi & fanecchissimo,
THANKS for your opinions...
I'm putting all my cards on the table re my problem:
1st. 99% of my cacti collection, are grown from seeds by myself.
2nd. This is on Astrophytums ONLY after 27 years.
3rd. Not on all astros, BUT on the NEW cultivars from China, Japan and Thailand (Cuttings).
4th. Also from seeds (Astros. NEW cultivars) from: Czechoslovakia, Germany, Italy and Malta.
5th. I do not heat my greenhouses.
6th. In January temperature goes down to 0C inside the greenhouse.
7th. I never had this problem in 27 years.
8th. Marks are only on the outside and not inside.
THANKS again for your HELP...

[fanecchissimo]

i noticed too that some plants are genetically susceptible from this pathology. good plants don't. for this i actually buy quite only seeds, and select if i see some wich become spotted... i destroy them.

[cortona]

i can give you my little 20 cents of experience: the problem are humidity, wen it stay too much on the plant surface in form of water and temps drop near 0 ° the result are this you can find this brown spot just in place were umidity can stay so no apex. let me know if this match your observations.

[marazz53]

Hi fanecchissimo, THANKS for your opinion. I did not understand 1 answer from you, "good plants don't"? As I said, the cuttings are all from good plants, (offsets) and the seeds too.

[marazz53]

Hi cortona, THANKS for your opinion. I will do anything to stop this problem of mine. I will put a drop of water on a nice plant and see what happens and let you know.

[Arioandi]

I had the same or similar spots on a big A. asterias 'Ooibo Ruri Kabuto'. Normally I heat the greenhouse to 10-12°C in wintertime, last winter only 8°C. The plant was from Thailand.

I thought, 8°C was to cold for this plant. Maybe the plant had also an infection with a virus. Maybe the virus made the spots.

It is possible, that with lower temperatures the air humidity becoms higher, so little condensate can be on the plant, so fungus infections have a perfect climat.

Anyway, that are just considerations. I lost the plant in spring...

[fanecchissimo]

@marazz:i noticed that just some of the plants has spots, even from good parents, and if i find those, i destroy them.

in my greenhouse the problem was worse in the summer, so i don't know if cold is the problem.

i once tried with anti transpirants, but the result was a total disaster... more spots than ever..
so maybe it is a problem of transpiration...

but i am not a big expert...

[Carlo & Daniele]

hello!
according to our experience, this problem is more serious on nudum forms. On white forms the problem probably is latent and they do not show it on the skin. Personally we think it's due to humidity and lack of air. This year we put some plants outside the greenhouse in full sun and it seams that dry air, direct sun and rain works good on them.

[marazz53]

THANKS, Andi, fanecchissimo and C&D for your opinions. Last week I sprayed ALL my plant with "Previcur", maybe it helps and I bought another fungicide (Ganzo) to try it too, I will spray them ALL again next week.

[fanecchissimo]

miclobutanil (ganzo) is a triazole, the kind i suppose should work in some way.

i can't find information of t 1/2 of it... sorry.

[marazz53]

Hi fanecchissimo, THANKS for your interest. I bought it cos I made a survey of what use to come to Malta and now they stopped them cos of the European rules. What I did I asked my wives's brother who is a farmer what is the equivalent of "Saprol" cos I use to hear his father that they use to use it against rust on onions, so I said I'll give it a try, so I had to buy it to try it. I will let you know about the experiments that I'm doing and the result. I bought this Ganzo about 4 months ago, but I was trying other products and I was quite busy in the greenhouse. Re information I have a leaflet with the product...

[marazz53]

[marazz53]