Rebutia flavistyla problem

[AndrewB]

Hi Ed,

I use Bug Clear Ultra, not specifically aimed at RSM but it deals with mealies very effectively at the same time and I have read on several sources that it works on RSM. From my experience it does seem to work on RSM. Although I have also had a few stubborn cases that needed several doses of contact insecticides. I’m not going to my shed this time of night to find the name of the contact insecticide though!

I think the predators are a good general broad spectrum RSM reducing strategy between insecticide treatments.

[Ali Baba]

You need a good long gap between using any predators and using a persistent pesticide, predators are very sensitive to pesticide. Also the predators that eat red spider mite (Tetranychus) don't eat false spider/flat mites (Brevipalpus) which is widespread on cacti. Bearing in mind the cost of predators it would pay to ID your pest before you buy!

[habanerocat]

Just an update on this problem I'm having.

I've since lost all bar one of the plants in the above photos. They just shrivelled up and died over the winter. The Lobivia jajoiana seedlings in this thread have all died also.

viewtopic.php?f=1&t=170282&p=296837#p296837

So last couple of weeks I noticed this same problem on some Rebutia fibrigii seedlings. The same thing seems to be happening, they start to fade to yellow at the crowns and then turn brown and finally shrivel up.

I have another tray that doesn't seem to be infected yet. I've checked them with a lens and can't see any mites. I'm a bit lost as to what's going on here. Both trays have been sprayed with SB Plant Invigorator three times since Late March.

Any ideas?

[Ali Baba]

Boron deficiency?

[MikeT]

Boron deficiency?

That was my second thought. First was rsm, especially on Rebutias, but that usually affects the whole batch of seedlings to a similar extent - at least it does for me. Were the seedlings planted into new compost? I wouldn't expect boron deficiency so quickly.
I don't have a third thought yet.

[AndrewB]

These plants have been grown from seed in 2017 and were going well. Despite not being fertilized they have flowered and have shown lush growth since being re-potted this spring.

Hi, in your first post you mention you have not fed your seedlings since repotting, if these were my plants I would be thinking it’s time for a feed. They could be starving, having exhausted all the nutrients in the compost.

I feed my plants almost every time I water, 9 out of 10 times.

[habanerocat]

It's most likely I added this to the potting mix of gerneral JI2 and grit at 50/50.
All comments welcome, thanks!

[Ali Baba]

You’ll need to use a fertiliser with micronutrients to get boron included

[el48tel]

Do Rebutia flavistyla like a high calcium and alkaline environment?

[Ali Baba]

Do Rebutia flavistyla like a high calcium and alkaline environment?

No