tainted lophophora

[Pete]

hello all,

one loph. plant under my responsibility is tainted (lower periphery):

i looked carefully for scale or mites, using a magnifying glass, with no results (nothing's seen)

the taint is slowly expending though.. can someone speculate/ diagnose this condition? any treatment?

thanks

[tripsis]

Have you checked the roots for any signs of infestation?

[dbbard]

Stop watering

[Garbage]

Cork.

[mr b.caapi]

Cork.

??

[Pete]

Have you checked the roots for any signs of infestation?

yep, looked at the roots. didn't remove all the soil, but generally, they looked fine to me.

[Pete]

Stop watering

imo, it can hardly be water-related, (1) they're not getting any water for several weeks (winter), (2) few additional lophs from the same batch (and similar water regime) looks quite all right.

[M S Smith]

Looks like red spider mites. They are quite microscopic, but you can almost see them as little red dots on your plant. Spray with Schultz insect spray which has pyrethrin every other day for three cycles. The damage will eventually grow out. Here's an L. diffusa before, during and after.

~Michael~

Edited November 22, 2009 by M S Smith

[Pete]

Cork.

cork might be a form of defence against various attackers. but this seems so pervasive

[Pete]

Looks like red spider mites. They are quite microscopic, but you can almost see them as little red dots on your plant. Spray with Schultz insect spray which has pyrethrin every other day for three cycles. The damage will eventually grow out. Here's an L. diffusa before, during and after.

thanks a lot. i saw these red spots (only on the digital image; not directly with the magnifying glass). didn't realize the beasts are that small. that's a very impressive (and reassuring) recovery on that difussa. thanks a lot for the treatment recipe.

[kadakuda]

thats a real good visual Michael!

[Ace]

Agreed with Michael - mites. They are quite a pain to control because their populations soon explode and will move on to any and all cacti in the area. Killing them off as soon as possible will limit the scarring they cause, but there's no way to reverse it. Luckily, as in Michael's diffusa photos (which are fantastic, BTW), a happy plant will soon enough grow out of the scarring and look good as gold in a few years.

Another alternative to pyrethrum is using dishwashing liquid diluted in tap water (just a tiny bit in the spray bottle then top up with plenty of water) and spray onto affected plants (spray once or twice a day, morning and evening). The mites soon pack their bags and leave. Apparently they don't like a soapy plant, but overdoing it and keeping the soil too moist can also create rot problems, so don't overdo it.

[karode13]

Mites don't like water full stop.

If you spray your plants with just water twice a day they will move along, they hate humidity. Pyrethrum will do the job effectively though.