Q.rose bush disease
The flower won’t pass the stage of a small bud because it becomes brittle and folds within itself encasing the flower. At touch it feels brittle and brakes at small pressure.
I have to try to liberate each bud but sometimes it isn’t possible and the flowers wither
It sounds like you have perhaps a Thrips or Sawfly problem, most likely Thrips. If you can get a product called Bayer Tree & Shrub Granules where you are, I recommend buying some and giving your rosebushes a treatment of it per the label instructions for Ornamentals / Roses. It is a systemic and will get at these tiny pests that are not easy to spot. If you cannot get this product, then I recommend looking at your local garden center for a systemic product that is listed for use on rosebushes that lists thrips and sawflies on the label as pests it will control. Here is an article link for you as well, but I do believe the problem you are having is one of the two pests listed. Link: https://www.gardeningknowhow.com/ornamental/flowers/roses/no-blooms-on-roses.htm
Here is another article link for you as well: https://www.gardeningknowhow.com/ornamental/flowers/roses/rose-thrips.htm
