Scarring on cactus

[Xannydoo]

Can someone help me identify what the problem is here? I have bad scarring on about 7 cacti in my collection. I have been presuming that it was caused by an application of Confidor last year, even though I am very careful to spray when it's not hot. Now I'm wondering if it's something else. Different genera affected but mostly lobivia. Any ideas please?

[cactuspip]

If you were in England i would say it was red spider bite damage.

It is a very small insect that pierces the epidermis, particularly around the growing point. These incisions lead to the typical brown scarring, like on your plants.

I would try some insecticide. It does grow out, but can take quite some time.

[KarlR]

Red spider mite for sure. They love Lobivia, Rebutia and Sulcorebutia. Lophophora too. You will often see them on these genera first but they will soon spread to others. Left unchecked they can ruin a collection.

There are several threads here on how to deal with them. Some swear by insecticidal soaps (which are the easiest to come by, or make yourself), but for my collection the only thing that worked was a proper miticide (though you might have to look on Ebay or similar to find any - and they're usually pricey).

[Xannydoo]

Thankyou so much, I wish I had asked sooner! Do I treat all my cactus with a miticide or just the affected ones?
I've just done a Confidor spray so would I need to wait? All these chemicals make me nervous! Thanks again , I feel stupid for not thinking it was a pest.

[habanerocat]

Have a look here.

viewtopic.php?f=1&t=166990&hilit=red+spider+mite

You'll need to spray everything to be sure. Staging, pots, you can't be thorough enough.

[Ivan]

With some patience you can be rewarded. I fought with this baldianum for over 2 years and left it without soil. I just soaked it in soapy water every few months. We really don't have any chemicals available here so I just washed the mites off. I was not happy with the damage but as you can see it doesn't look so bad now.

G. baldianum 2016

G. baldianum 2018

[KarlR]

I don't believe Confidor is useful for mites. Imidacloprid which is the active substance in it is not a miticide as far as I know. If you have a large collection I would considef finding a good miticide. If you have a small collection I would consider soap to probably be the most sensible solution.

And yes, you should spray everything. And you will almost certainly have to spray more than once unless you get a really good systemic miticide.

[iann]

Despite all the good advice about sprays, it would be best to identify the pest first. Very good eyes, a magnifier, or a decent camera macro function should show you any pests. They will be less than a mm long, but unmistakable once you spot them.

The damage certainly looks like mites, but could possibly be something else. It is even possible that there were once mites and they're now gone. It would be a shame to risk damage with chemicals, or spray ones which are not effectively against your particular pest.

[Xannydoo]

Thankyou everyone for your informative advice! I have read previous thread and decided on using Eco oil as a miticide( I already have some) . I have discovered about 11 plants affected, but so far have not been able to see any pests at all. I will have a better look on the weekend in sunlight as I haven't been home in daylight this week!
I would say that I have had this problem for a year ( stupidly not thinking pest because I couldn't see any) and affected plants are sulcorebutia, lobivia , rebutia and Echinocereus. I'm probably lucky that more plants aren't affected.
My collection is in two standard size glasshouses and I will spray everything just in case.( Last weekend I just sprayed Confidor for mealy bug as I had found an affected plant ) It's winter here and I'm not liking wetting my cacti but I guess it's not too much moisture.