I followed three different approaches in last three years to deal with aphids & thrips. These are basically sap sucking insects that come on the fresh growth.

Last to last year, I used neem water (not neem oil) and tobacco water. Both were very effective against aphids, specially neem water that I used to make by boiling neem leaves. However, it was quite a hassle preparing these solution once in 10 days as aphids would come again. More importantly, both neem water as well as tobacco water killed the beneficials too which was highly undesirable. So I wanted a permanent organic solution; a preventive measure that would discourage aphids in my garden.

Last year, looking for an effective preventive measure, I went for a high Ca and low nitrogen therapy. Low nitrogen puts a check on rapid growth and Ca hardens the tissue walls. So we are looking at hard tissues with less inter-tissue gap which makes the fresh growth on a rose bush un-attractive for the sap sucking pests. Again a success and there were hardly any aphids or thrips on my roses last year. But I had a price to pay.... over doze of Ca resulted in lighter shades and low fragrance in my roses. Even those roses that have the reputation of being most fragrant had mediocre fragrance.

This year I adopted the approach that was similar to what Valrose wrote. I just asked myself that how much of damage aphids or thrips caused? Not much perhaps, unless there are too many of them. So I decided to live with the aphids and thrips on my rose bushes this year and when I saw too many of them on a bush, just sprayed it with a water jet. Used nothing against them. It was much easier and I have had no issues with aphids so far.

I would recommend the third approach. I would let the nature work and only interfere when it is necessary or un-avoidable.

best regards