Well bought a new beauty a weekend ago and love it! Only now I've noticed it's got these white fluffy things on it?
I'm also still having a horrible time with my tall catic I thought they were dead so I was trying to take them out and the one I got out was 100% healthy on the inside. I felt horrible for not knowing it was healthy! I see now the healthy growth on the top but it's got these grey dark scales
Thats mealy bug kind of like aphids they eat plants a common pest of succulents including cactus. I would cut the flower stalks off and throw away are they on the plants also?
If they're on the flowers in those numbers they may also be prevalent on the main body of your plants. Do a very detailed inspection and try and report back.
Def want to cut that flower off, it will not harm the plant, ensure you throw the infected flower part faaarr away from your plants. Preferably in a dumpster lol.
mealybugs are difficult to eradicate and quite injurious to plants. There is a good thread posted by Steve Johnson with the headline "Mealies, and flat mites, and scale. oh my". You could read what Steve is suggesting. You may need to apply both a topical and systemic insecticide, in order to eliminate the pest population. For those that are on the outside of the plant, even picking them off with a brush dipped in isopropyl alcohol will be effective to a certain degree. I would however go with a systemic insecticide applied with the irrigation water.
As far as the lesions on your columnar cactus are concerned, I cannot tell what the cause is, because you do need to show individual lesions close up, as close as your camera will allow. There seem to be two different kinds of lesions: some of darker color and some that are gray. They could be caused by a multitude of things, including non-pests, pathogens, etc.. Especially columnar cacti tend to develop splotches, which may be caused by too hot or cold conditions, mechanical injury and other things.
It is also important to inspect for pests plants that you buy and bring home and separate new plants under quarantine for couple of weeks. Otherwise these bugs will infect all plants of the collection and eradication would be extremely hard.
You can also try spraying plants with oil emulsion. This control different pests even the effect might be temporal.
If your cacti mess in your job just forget about the job.
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I thought they were dead so I was trying to take them out and the one I got out was 100% healthy on the inside. I felt horrible for not knowing it was healthy! I see now the healthy growth on the top but it's got these grey dark scales
my mom just bought that for me. Is that what's also happening to my tall cacti? 
