Something wrong with my Ferocactus?

[Mrs.Green]

I have had this Ferocactus for a few days only. It’s about 15 cm. in diameter. Today I noticed it ‘sweated’ several places. The ‘sweat’ is clear as water as shown . I have also noticed the black/grey discoloration of the areoles ans some spines seems to missing. What is this ‘sweat’ and could ut be a connection between the ‘sweat’ and the discolorarion of the areoles? I am thinking of a type of black rust?

Is this harmless or is this something to worry about?

[jerrytheplater]

In Cacti for the Connoisseur by John Pilbeam published by Timber Press in 1987 under Ferocactus he says, "Precautions should be taken against the formation of unsightly "sooty mould", a fungus which forms on the copious sugary sap exuded from the glands just above the aeroles which these plants all have. Continual spraying overhead (preferably with rainwater or distilled water to avoid marking the plants) helps by dissolving the sap, and occasional fungicide sprays will help combat this disfiguring mould."

[greenknight]

Jerry's right, Ferocacti are among the plants which have extrafloral nectaries. In habitat, the nectar they secrete attracts ants, which benefit the plant. See: https://www.indefenseofplants.com/blog/ ... -and-cacti

If there are no ants to consume the nectar, it may grow mold and look unsightly. I've never had this problem, personally, since we're overrun with tiny black moisture ants.

[Mrs.Green]

Thank you very much, Jerrytheplater and Greenknight . This is very interesting information ! Since my Fero is indoors it will not benefit from ants but at least I am not worried about the soot.

[greenknight]

Be glad that you don't "benefit" from ants in your house. My cacti summer outside, but the ants are indoors and out.

[Mrs.Green]

Be glad that you don't "benefit" from ants in your house. My cacti summer outside, but the ants are indoors and out.

You have a point there.. Ants indoors is a rare sight here.

[anttisepp]

Nice F. swarzii with nectaroferous spines.

[Mrs.Green]

Nice F. swarzii with nectaroferous spines.

Thank you very much Anttisepp

[toadstar]

Do you like ants? This is how you get ants.

[Mrs.Green]

Do you like ants? This is how you get ants.

Great pic! I do like ants, as long as they don’t are in my house Since we have a lot of Norway spruce in my area ( Picea abies) , we also have lots of ants, who build impressive antheaps of the needles , some really big! It’s wise to look around before you sit down on the ground, unless you want the ants to examine your body..