Aphid at Cactus root

On New Year holidays, I had free time to notice that my poor astro. baby cactus became flatter and smaller.  When I removed them out of the pot, I got the answer: aphid stayed at the root.  This awful insect suck the juices of root for food.  I think it was because I rarely sprayed the chemical insecticide.  I usually use the organic one which may not be strong enough.

You can see the small white thing in the soil.  This is evil aphid.

After realizing the problem, I also washed and cleansed the cactus root in water.  I tried to remove all soil and dust from the root softly.  If do severely, the root might be damaged and the recovery will take longer time.

Here is the cactus after I scrubbed all soil.  It becomes bare root now.

I'll leave them like this for several days and plant in the pot later.  Hope you guys will have time to care your cactus, not ignoring them like I did.