What can i do for those insects?

I dont see cobwebs, the problem is my girl enter 4th week of flowering and it is too bad to foliar spray.. I dont know what to do, Population is not so high yet but wondering if population get high fast..

are there cobwebs on the leaves? it is very similar to spider mites. if you find a pputin or you can examine it and recognize it, then a systematic solution of the issue will be required. you will have to do several treatments for a tick, as it has several stages of incubation and it is not enough for you to eliminate only visible individuals on the leaves, as new ones will hatch soon, you need to find a remedy in your city and do several treatments with an interval of 7-10 days (maybe less often, you need to look at the instructions for a specific tool)

Photos are not real good...........but aphids do live under the leaves and have nothing to do with roots, they are (leaf) "sap suckers". Close up clear pics of the exact insect/s would help immensely.

photos are blurred , i understand, that mostly you will meet aphids on stems and top shoots, but it remind me of, make a better photo. this page has everything for each bug. i bought against 2x thrips and 1x gnats from them - all did magic.

Also i dont think they are aphids. If its aphids they wont be on the bottom side of ur leaf. They will find the way to your roots. Like i said earlier best is to find a predator. They will take care without u having to put in much effort.

These can be spidermites or thrips. What i did during my infestation is: i got predatory mites and green layswings. The layswings eat all those bugs and then fly off it was gone in 4 days for me.

I never had them, justt in chilhood on roses, we used soap, but for canna i jever would do it. With all pests i went natural predators way, i have huge allergy and dont want to risk with any sprays. https://www.dragonfli.co.uk/collections/aphids?src=GAds&gclid=Cj0KCQjwteOaBhDuARIsADBqReip6ut7M_P_lFHX3dIUPymex6Eks8TyyI1Izft61QcfpQqb4yfwenEaAnYgEALw_wcB Sticky traps and prevention is a must, plus find in your country alternative ... Everybody swears by dr Zymes. Google it. I never used.

then what can i do for them ?

to me looks like aphids, they have many variations ... https://www.google.com/search?q=aphids&client=firefox-b-d&source=lnms&tbm=isch&sa=X&ved=2ahUKEwifoeqosP36AhWQh1wKHf0vAckQ_AUoAXoECAIQAw&biw=1536&bih=731&dpr=1.25