Question
Hi, i started collecting cacti about three years a go, and a few have even flowered for me, but this yaer i have noted the a few have started to get a sticky white crystal forming near there spins and some by there roots .They still seem health no rot spots or softening ect, could this be a fungal problem ,and how do i treat it.I live in the uk and the weather has been a bit diffrent this summer (very cold untill a couple of weeks ago then we had a heat wave which was very humid . Thank you for your time ,anne-marie.

Answer
Dear Anne-Marie

If they are "crystals", then it is probably an accumulation of moisture and either some type of fertilizer or even salt crystals. Are the plants indoors or outside? This would be more of an issue outside, because if they are inside and your place is air conditioned, air conditioning removes moisture from the air.

It doesn't sound like a fungus to me as a fungus will generally remain soft and irregular in shape, whereas a crystal will be hard and angular. Hopefully this helps.

Sincerely,

Greg