Jasmine has lost its leaves

Question: jasmine has lost its leaves

Good morning,
I have 2 Rhyncospermum jasminoides in pots on the balcony (more or less from 1 year). I live in Alexandria, so to overcome the harsh winter I covered them with non-woven fabric and it seemed to have worked.
About 20 days ago I discovered them, one of them is throwing a lot of new gems, the other one has lost almost all the leaves these days and for now has few gems but it is not dry.
We come to the questions:
When I discovered them, I wet them and I put some slow release fertilizer for flowering plants, instead of the usual liquid fertilizer, did I do well? and how often should the slow-release fertilizer be given?
I was away for 10 days and my husband bathed them every day, could it be radical rot?
and again, I believe that the plant that loses its leaves has a slight cochineal (the branches in some places have small white cobwebs, but very little stuff), does cochineal lose its leaves?
What should I do to recover?

Answer: jasmine has lost its leaves

Dear Barbara,
the rincospermo, trachelospermum jasminoides, is a very rustic climber, which can withstand temperatures even close to -15 ° C, therefore it is cultivated in the garden, throughout northern Italy, instead of the more classic jasmine of the genus jasminum, in order to avoid to have to protect it from the cold in winter; if then your plants are on the terrace, consider that they are already protected by the house, and therefore in my opinion it is not necessary to cover them with the woven fabric (unless you live in the high mountains). The cover with non-woven fabric and the terrace shelter may have caused periods of excessive drought to your plants, followed by regular watering; this change in the amount of water present in the soil may have favored the development of rot. But it is not said that the plant that suffers the most has lost its leaves for this reason, it could very well have lost them because it was less exposed to the elements than the other specimen, and therefore suffered more from drought during the winter. If, on the other hand, the soil of the pot has been exposed to water even in winter, it is more likely that it is actually a rot, which will have to be eliminated by using a systemic fungicide (that is, which enters the plant's circulation), and also leafy , or that they should be sprayed on the plant, on the remaining leaves, and from there it goes into circulation. These plants are very hardy and resistant, and do not need excessive care, so it would be better to avoid watering them every day, rather watering only when the soil is very dry. The cochineal often afflicts the pickups, but you should see the insects on the stems, and it hardly causes the fall of the foliage. The granular fertilizer is an excellent substitute for liquid fertilizer, and it is also more comfortable, because today and for the next four months or so your plants will not need to receive more fertilizer. Another reason why your plants may have lost their leaves is related to growing in pots: it often happens that in autumn insects lay their eggs near the stem of potted plants, where, once the larvae come out, they penetrate in the ground and devour the roots; it would therefore be advisable to repot two backwaters, or to spread an insecticide bait against the soil insects on the ground.