Because another topic has veered into this area it occurred to me that I recalled a New Scientist article some years ago which may be worth reading: https://www.newscientist.com/article/dn13620-evolution-24-myths-and-misconceptions there are various links to the sub-topics of which the two https://w...

What I would suggest though, is that cacti won't have developed hooked spines for no reason. But, if you'll forgive me, the curved spines did develop for absolutely no reason - they arose either from some simple mutation in a gene (less likely a mutation in more than one gene at the same time) or f...

That does make it likely to be damage within the skin - so definitely something to keep an eye on whatever the original cause especially if the brown areas get any larger, if there is a fungal infection it is likely to grow.

fingers crossed...

graham

I entirely agree with Dave's points, and, as he has pointed out, points that were being made from the outset, it's just very sad that 'survival of the fittest' caught on so well, but I suppose that 'non-survival of some of the less fit' doesn't really have the same impact. It's also risky to make as...

I would ask whether the 'marks' are actually on or in the skin ? The photos are fine but they don't really show whether this is some damage within the skin or something on and above the skin which would make it more likely to be an infection. Looking at the third photo I notice a rather round spot q...

Personally I prefer to always water from above and allow the water to drain away. The only exceptions are the occasions when I feel the soil needs a good soak - if there is a problem with non water-retentive mixes it is that the water does tend to run through quite rapidly when the soil is very dry ...

... the treatment with Bacillius thuringiensis, because this works only in humid conditions. This isn't really true. I will accept that you have to water the soil to add the bacillus so that certainly does mean getting it wet but that need only be as a part of normal watering, that is there is no n...

Interesting notes about CAM in mesembs, Ian. Do you have a reference I could persue? As Ian hasn't replied, may I suggest just having a web search for "facultative CAM" and you will find plenty of references. The first link in my previous post "Drought-stress-induced up-regulation of...

There are some specific sciarid fly killers just search online and you'll find a few. Personally I've used 'Gnat Off' and found that it works pretty well. 'Gnat Off' contains Bacillius thuringiensis (Bt) and it is this that kills the larvae, indeed I believe that all of the specific sciarid fly trea...

Ah...I had forgotten about this...all of my four are up although one is a month later than the others for no reason that I can see, in fact they are potted two to a pot so the late one had exactly the same treatment as its partner in the pot (well within reason). They are with some other summer grow...